CN108259091A - A kind of time-domain filtering installation method and device - Google Patents

Abstract

Embodiments of the present invention relate to the communication field, and in particular to a time-domain filtering device, method and device, which are used to achieve the effect that the phase modulation of the first signal light is independent of the polarization of the pulsed pump light. In the embodiment of the present invention, the first phase modulation is performed on the phase of the first signal light by the pulsed pumping light, and the polarization of the first signal light after the first phase modulation is rotated by 90 degrees, and the pulsed pumping light is used to The phase of the first signal light that undergoes the first phase modulation and the polarization rotation is subjected to the second phase modulation, and the first signal light that undergoes the polarization rotation and the second phase modulation and the second signal light that is not subjected to the phase modulation are sent to the first port. Since the polarization of the first signal light after the first phase modulation is rotated by 90 degrees and then the second phase modulation is carried out by the pulse pump light, the phase modulation of the first signal light and the pulse pump light are achieved. Polarization independent effect.

Description

A time-domain filtering device method and device

technical field

Embodiments of the present invention relate to the communication field, and in particular, to a time-domain filtering device, method and device.

Background technique

An optical switch is a device that converts the optical signal of one optical channel to another optical channel according to certain requirements. The optical switch can enable direct switching between optical paths, and is the core device to complete all-optical switching in the optical network. With the expansion of the all-optical network market, the research on optical switches has increasingly become the focus of attention in the field of all-optical communication.

Fig. 1 exemplarily shows a structural diagram of a time-domain filter optical switch provided in the prior art. As shown in Fig. 1, a beam of light enters a 3dB optical coupler 103 through a port 101, and the beam of light passes through a 3dB light After the coupler 103, it is divided into two beams, which enter the Sagnac (Sagnac) ring 104 from the left and right directions respectively. The optical path of the light in the fiber is always equal, and the interference occurs in the 3dB coupler at the same time after running for one week. If the phase difference between the light transmitted clockwise and the light transmitted counterclockwise is 0, the light beam after interference will exit along the direction of the port 101, and the Sagnac ring acts as a reflector at this time. If the phase difference between the light propagating clockwise and the light propagating counterclockwise is π, the light beam after interference will emerge from the direction of the port 102 . If the phase difference between the light transmitted clockwise and the light transmitted counterclockwise is between 0 and π, both ports 101 and 102 will emit light, and the specific output splitting ratio is determined by the phase difference.

In the prior art, a beam of strong pump light is usually cross-phase-modulated with the clockwise or counterclockwise transmitted light in the Sagnac ring, thereby generating a nonlinear phase shift, so that the clockwise transmitted light and the counterclockwise transmitted light A phase difference is formed between the lights.

However, in the above scheme, since the nonlinear phase shift is related to polarization, that is, the polarization of the pump light will affect the phase difference between the light transmitted clockwise and the light transmitted counterclockwise, it is difficult for the above scheme to pass the pump light The nonlinear phase shift effect of the obtained accurate clockwise transmitted light and counterclockwise transmitted light phase difference.

Contents of the invention

Embodiments of the present invention provide a time-domain filtering device, method and device for achieving the effect that the phase modulation of the first signal light has nothing to do with the polarization of the pulsed pump light, so as to obtain the first signal light and the second signal light more accurately phase difference.

An embodiment of the present invention provides a time-domain filtering device, including a coupling unit, a processing unit connected to the coupling unit; a pulsed pump light generation unit connected to the processing unit; the coupling unit includes a first port and a second port. The coupling unit is used to receive the signal light, divide the signal light into the first signal light and the second signal light, and send the first signal light to the processing unit; after receiving the polarization rotation sent by the processing unit, a second phase is performed In the case of modulated first signal light, the first signal light with polarization rotation and second phase modulation and the second signal light without phase modulation are sent to the first port of the coupling unit; In the case of the first signal light without phase modulation, the first signal light without phase modulation and the second signal light without phase modulation are sent to the second port of the coupling unit.

The pulsed pumping light generation unit is used to obtain the indication information, and generates the pulsed pumping light according to the indication information; and sends the generated pulsed pumping light to the processing unit; the processing unit is used to send the pulsed pumping light after receiving the pulsed pumping light generation unit In the case of the pulsed pumping light, the phase of the first signal light is phase-modulated for the first time by the pulsed pumping light, and the polarization of the first signal light subjected to the first phase modulation is rotated by 90 degrees to obtain the first The second phase modulation and polarization rotation of the first signal light, the second phase modulation is performed on the phase of the first signal light with the first phase modulation and polarization rotation by the pulsed pump light, and the polarization rotation is obtained and the second phase is performed modulated first signal light, and send the first signal light with polarization rotation and second phase modulation to the coupling unit; if the pulse pump light sent by the pulse pump light generation unit is not received, there will be no The phase-modulated first signal light is sent to the coupling unit.

In the embodiment of the present invention, the signal light is divided into the first signal light and the second signal light; pulse pump light is generated according to the instruction information; in the case of pulse pump light, the pulse pump light is used to control the first signal light The phase of the first phase modulation is performed, and the polarization of the first signal light after the first phase modulation is rotated by 90 degrees to obtain the first signal light with the first phase modulation and polarization rotation, and the pulsed pump light is used to The phase of the first signal light that undergoes the first phase modulation and the polarization rotation is subjected to the second phase modulation to obtain the first signal light that is the polarization rotation and the second phase modulation is performed, and the polarization is rotated and the second phase modulation is performed The first signal light without phase modulation and the second signal light without phase modulation are sent to the first port; in the absence of pulsed pump light, the first signal light without phase modulation and the second signal without phase modulation Light is sent to the second port. After the first phase modulation of the first signal light is performed by the pulse pump light, the polarization of the first signal light after the first phase modulation is rotated by 90 degrees, and then the second phase is performed by the pulse pump light. Modulation, so that the phase modulation of the first signal light is independent of the polarization of the pulsed pump light, so that the phase difference between the first signal light and the second signal light can be obtained more accurately.

Optionally, in the embodiment of the present invention, dividing the signal light into the first signal light and the second signal light specifically refers to dividing the signal light into the first signal light and the second signal light in terms of power. The coupling unit may be a 1×2 fiber coupler, or other optical devices capable of distributing or combining optical signal power among different optical fibers. Optionally, only the power of the signal light is distributed through the coupling unit, that is, the power of the first signal light and the second signal light can be the same or different, but other parameters of the first signal light and the second signal light are the same, For example, parameters such as wavelength, polarization, and phase are the same.

Optionally, the coupling unit 213 can be a coupler capable of two inputs and two outputs, which can split and combine the two optical signals, and according to the phase difference of the two received optical signals, the received After combining or interfering, the two optical signals are output from corresponding ports of the coupling unit 213, which may be, for example, a 3dB optical coupler.

Optionally, the coupling unit further includes a third port and a fourth port; the coupling unit is configured to: receive the signal light through the second port, and split the signal light into the first signal light and the second signal light; sending the first signal light to the processing unit; sending the second signal light through the fourth port; receiving the first signal light with polarization rotation and second phase modulation or the first signal light without phase modulation through the third port; Receive the second signal light without phase modulation through the fourth port; in the case of receiving the first signal light with polarization rotation and second phase modulation sent by the processing unit through the third port, it will be received through the third port The received first signal light with polarization rotation and second phase modulation and the second signal light without phase modulation received through the fourth port are sent to the first port of the coupling unit; In the case of the first signal light without phase modulation sent by the unit, the first signal light without phase modulation received through the third port and the second signal light without phase modulation received through the fourth port Send to the second port of the coupling unit.

Optionally, the coupling unit includes four ports, and the signal light can be received through the second port 227, and the signal light can also be received through the first port 226. In this embodiment of the present invention, only the second port 227 is used as an example for introduction. If the signal light is received through the first port 226, the time-domain filtering device can play a role of reflection, and the received signal light returns directly from the first port 226 without being modulated.

Optionally, the processing unit includes: a multiplexing/demultiplexing unit connected to the pulsed pump light generating unit and the coupling unit, a dielectric unit connected to the multiplexing/demultiplexing unit, and a first Faraday rotator connected to the dielectric unit A mirror unit; a multiplexing/demultiplexing unit, which is used to perform pulsed pumping light and the first signal light sent by the received coupling unit in the case of receiving the pulsed pumping light sent by the pulsed pumping light generating unit Coupling to obtain the first coupled signal light; sending the first coupled signal light to the medium unit; demultiplexing the fourth coupled signal light to obtain the first signal light with polarization rotation and second phase modulation, and rotating the polarization And the second phase-modulated first signal light is sent to the coupling unit; the medium unit is used to make the pulsed pump light in the first coupled signal light pass through the medium unit to the first signal light in the first coupled signal light The phase is first phase modulated to obtain the first signal light for the first phase modulation and the second coupled signal light coupled with the pulsed pump light, and the second coupled signal light is sent to the first Faraday rotating mirror unit; The pulsed pump light in the third coupled signal light performs a second phase modulation on the phase of the first signal light in the third coupled signal light that undergoes the first phase modulation and polarization rotation in the dielectric unit, and obtains the second phase modulation The phase-modulated and polarization-rotated first signal light and the fourth coupled signal light coupled by the pulsed pump light, and the fourth coupled signal light is sent to the multiplexing/demultiplexing unit; the first Faraday rotating mirror unit is used to In the second coupled signal light, the polarization of the first signal light after the first phase modulation is rotated by 90 degrees, and the third coupled signal is obtained by coupling the first signal light with the first phase modulation and polarization rotation and the pulsed pumping light. light; sending the third coupled signal light to the medium unit.

There are various implementation schemes for the dielectric unit in the embodiment of the present invention, as long as the pulsed pump light can have a non-linear effect on the first signal light and the first signal light with the first phase modulation and polarization rotation in the dielectric unit, Therefore, it is enough to perform the second phase modulation on the phase of the first signal light and the phase of the first signal light that undergoes the first phase modulation and polarization rotation. For example, the medium unit can be a Kerr (Kerr) medium. Specifically, it can be Ordinary single-mode optical fiber, photonic crystal optical fiber, silicon wire waveguide, quantum dot and other media with third-order nonlinearity.

In the embodiment of the present invention, since the pulsed pumping light is some pulses with intervals in time, the multiplexing/demultiplexing unit will receive the pulsed pumping light in a continuous period of time, and the pulsed pumping light will be received in the next continuous time period. No pulsed pump light is received on the segment. That is to say, in the embodiment of the present invention, when pulsed pump light is received, the first signal light with polarization rotation and second phase modulation and the second signal light without phase modulation will be output through the first port , in the embodiment of the present invention, when the pulsed pump light is not received, the first signal light with phase modulation and the second signal light without phase modulation are output through the second port, so that the embodiment of the present invention The switching function of the time domain filtering device can be realized by connecting the first port and the second port of the time domain filtering device to different devices.

Optionally, the multiplexing/demultiplexing unit is further configured to: pass the received first signal light sent by the coupling unit through the medium when the pulsed pumping light sent by the pulsed pumping light generating unit is not received The unit is sent to the first Faraday rotating mirror unit; the first Faraday rotating mirror unit is used to rotate the polarization of the first signal light received by 90 degrees to obtain the first signal light without phase modulation; The first signal light is sent to the coupling unit sequentially through the medium unit and the multiplexing/demultiplexing unit.

In the embodiment of the present invention, the first Faraday rotator does not rotate the polarization of the pulsed pump light in the second coupled signal light. Optionally, the rotation angle of the magneto-optic crystal in the first Faraday rotator mirror unit to the polarization of the first signal light in the embodiment of the present invention is related to the wavelength of the first signal light, which can be achieved by selecting a specific magneto-optic crystal and pulse The wavelength of the pump light makes the entire first Faraday rotator mirror unit not rotate the polarization of the pulse pump light, but only acts as an ordinary reflector, and the reflected pulse pump light will continue to rotate 90 degrees with the polarization. The first signal light passes through the dielectric unit, so that a nonlinear interaction occurs, and optionally the intensity of the nonlinear phase shift has a linear relationship with the intensity of the pulsed pumping light.

Further, in order to maintain the same polarization state of the two signal lights reaching the coupling unit, optionally, the time domain filtering device further includes a second Faraday rotating mirror unit connected to the coupling unit; the second Faraday rotating mirror unit is used for: receiving the second signal light sent by the coupling unit, rotating the polarization of the second signal light by 90 degrees to obtain the second signal light without phase modulation, and sending the second signal light without phase modulation to the coupling unit; coupling The unit is configured to: in the case of receiving the first signal light with polarization rotation and second phase modulation sent by the processing unit, combine the first signal light with polarization rotation and second phase modulation with the first signal light without phase modulation The second signal light is sent to the first port of the coupling unit; in the case of receiving the first signal light without phase modulation sent by the processing unit, the first signal light without phase modulation and the first signal light without phase modulation The second signal light is sent to the second port of the coupling unit.

In order to make the light intensity of the two optical signals received by the coupling unit basically the same, an attenuation unit is set on the optical path of the second optical signal, so that the losses of the left and right channels are the same, and then complete interference occurs at the coupling unit Optionally , the time domain filtering device also includes: an attenuation unit connected to the coupling unit, a second Faraday rotating mirror unit connected to the attenuation unit; the attenuation unit is used to: receive the second signal light sent by the coupling unit, and perform the second signal light Attenuate for the first time, obtain the second signal light after the first attenuation, send the second signal light after the first attenuation to the second Faraday rotating mirror unit; receive the second Faraday rotating mirror unit to send the first attenuation and The polarization-rotated second signal light is attenuated for the first time and the polarization-rotated second signal light is attenuated for the second time to obtain the second signal light without phase modulation, and the second signal light without phase modulation is sent to the coupling unit; the second Faraday rotating mirror unit is used for: receiving the first attenuated second signal light sent by the attenuation unit, and rotating the polarization of the second signal light after the first attenuation by 90 degrees to obtain the first The second signal light attenuated and polarized rotated for the second time, and the second signal light attenuated and polarized rotated for the first time is sent to the attenuation unit; the coupling unit is used to: receive the polarization rotation sent by the processing unit and perform the second signal light In the case of the first signal light with secondary phase modulation, the first signal light with polarization rotation and second phase modulation and the second signal light without phase modulation are sent to the first port of the coupling unit; In the case of the first signal light without phase modulation sent by the unit, the first signal light without phase modulation and the second signal light without phase modulation are sent to the second port of the coupling unit.

Optionally, the signal light is a quantum optical signal, the first signal light is a first quantum optical signal, and the second signal light is a second quantum optical signal; the first port is connected to a quantum optical signal receiver; the pulse pumping light generation unit, Used for: receiving synchronous optical signals; determining indication information according to synchronous optical signals; wherein, the indication information indicates the pulse time information of the quantum optical signal; generating pulsed pump light according to the indication information; wherein, the pulse time information of the pulsed pump light Matching with the pulse time information of the quantum optical signal.

In specific implementation, the matching of the pulse time information of the pulsed pump light with the pulse time information of the quantum optical signal specifically means that one pulse of the pulsed pump light corresponds to a pulse of a quantum optical signal, and the corresponding pulse of the pulsed pump light There is an overlap region between the time taken and the time taken by the pulse of the quantum optical signal, and the overlap region is greater than the overlap region threshold. The duration occupied by the overlapping area is the duration when the time domain filtering device is in an on state when it is used as a switch. In another optional solution, the time taken by the pulse of the corresponding pulsed pump light completely coincides with the time taken by the pulse of the quantum optical signal. In this way, the pulse of each quantum optical signal can be obtained more accurately.

In practice, the quantum signal receiver can restore the original quantum secret key through the pulse of the quantum optical signal, while there are more classical optical signals or noise caused by other factors on other signals, if it enters the quantum signal receiver, it will cause the original The recovery rate of the quantum secret key decreases. In the prior art, the pulse of the quantum optical signal and the noise between the pulses of the quantum optical signal will enter the quantum signal receiver. The time domain filtering device provided by the embodiment of the present invention can realize extremely narrow filtering effect, this embodiment can greatly reduce the number of noise photons entering the quantum signal receiver, and improve the mixed transmission performance of the system. For example, the ability of a 100ps time-domain filtering device to suppress noise photons is 10 times that of a quantum detector in a 1ns gate-width quantum signal receiver.

An embodiment of the present invention provides a time-domain filtering method, the time-domain filtering method is executed by the above-mentioned device, and the time-domain filtering method includes:

receiving signal light, and dividing the signal light into first signal light and second signal light;

Obtain instruction information, generate pulsed pump light according to the instruction information; in the case of pulse pump light, perform first phase modulation on the phase of the first signal light by pulse pump light, after the first phase modulation The polarization of the first signal light is rotated by 90 degrees to obtain the first signal light that undergoes the first phase modulation and polarization rotation, and the phase of the first signal light that undergoes the first phase modulation and polarization rotation is performed by the pulsed pump light The second phase modulation obtains the first signal light with polarization rotation and second phase modulation, and sends the first signal light with polarization rotation and second phase modulation and the second signal light without phase modulation to The first port: in the absence of pulsed pump light, sending the first signal light without phase modulation and the second signal light without phase modulation to the second port.

Optionally, receiving the signal light and dividing the signal light into the first signal light and the second signal light includes: receiving the signal light through the second port; dividing the signal light into the first signal light and the second signal light; The third port sends the first signal light, and the fourth port sends the second signal light; the first signal light with polarization rotation and second phase modulation and the second signal light without phase modulation are sent to the first port, The method includes: sending the first signal light received through the third port with polarization rotation and second phase modulation and the second signal light received through the fourth port without phase modulation to the first port of the coupling unit; Sending the first signal light without phase modulation and the second signal light without phase modulation to the second port includes: receiving the first signal light without phase modulation received through the third port and the first signal light without phase modulation through the fourth port The received second signal light without phase modulation is sent to the second port of the coupling unit.

Optionally, in the case of pulsed pump light, the first phase modulation is performed on the phase of the first signal light by the pulsed pump light, and the polarization of the first signal light after the first phase modulation is rotated by 90 degrees, the first signal light that undergoes the first phase modulation and polarization rotation is obtained, and the second phase modulation is performed on the phase of the first signal light that undergoes the first phase modulation and polarization rotation through the pulsed pump light to obtain the polarization rotation And the first signal light for the second phase modulation includes: in the case of pulsed pump light, coupling the pulsed pump light and the first signal light to obtain the first coupled signal light; combining the first coupled signal The light is sent to the medium unit, and the phase of the first signal light in the first coupled signal light is phase-modulated for the first time in the medium unit through the pulsed pump light in the first coupled signal light, and the phase modulation of the first time is obtained. The second coupled signal light coupled with the first signal light and the pulsed pump light; the polarization of the first signal light after the first phase modulation in the second coupled signal light is rotated by 90 degrees to obtain the first phase modulation and The third coupled signal light coupled with the polarization-rotated first signal light and the pulsed pump light; the third coupled signal light is sent to the dielectric unit, and the pulsed pump light in the third coupled signal light is coupled to the third coupled signal light in the dielectric unit In the signal light, the phase of the first signal light that undergoes the first phase modulation and polarization rotation is subjected to the second phase modulation, and the first signal light that undergoes the second phase modulation and polarization rotation is coupled with the pulsed pumping light. Four coupled signal lights; demultiplexing the fourth coupled signal light to obtain the first signal light with polarization rotation and second phase modulation.

Optionally, in the absence of pulse pump light, before sending the first signal light without phase modulation and the second signal light without phase modulation to the second port, further comprising: In the case of , the polarization of the first signal light is rotated by 90 degrees to obtain the first signal light without phase modulation.

Optionally, sending the first signal light with polarization rotation and second phase modulation and the second signal light without phase modulation to the first port includes: rotating the polarization of the second signal light by 90 degrees to obtain The second signal light without phase modulation; the first signal light with polarization rotation and second phase modulation and the second signal light without phase modulation are sent to the first port; the first signal without phase modulation Sending the light and the second signal light without phase modulation to the second port includes: rotating the polarization of the second signal light by 90 degrees to obtain the second signal light without phase modulation; The signal light and the second signal light without phase modulation are sent to the second port.

Optionally, sending the first signal light with polarization rotation and second phase modulation and the second signal light without phase modulation to the first port includes: attenuating the second signal light for the first time to obtain the second signal light The second signal light after attenuation once; the polarization of the second signal light after the first attenuation is rotated by 90 degrees to obtain the second signal light with the first attenuation and polarization rotation; the first attenuation and polarization rotation will be performed The second signal light is attenuated to obtain the second signal light without phase modulation, and the first signal light with polarization rotation and second phase modulation and the second signal light without phase modulation are sent to the first port; Sending the first signal light without phase modulation and the second signal light without phase modulation to the second port includes: attenuating the second signal light for the first time to obtain the second signal light after the first attenuation; Rotate the polarization of the second signal light after the first attenuation by 90 degrees to obtain the second signal light that undergoes the first attenuation and polarization rotation; attenuate the second signal light that undergoes the first attenuation and polarization rotation to obtain The second signal light without phase modulation, the first signal light without phase modulation and the second signal light without phase modulation are sent to the second port.

Optionally, the signal light is a quantum optical signal, the first signal light is a first quantum optical signal, and the second signal light is a second quantum optical signal; the first port is connected to a quantum optical signal receiver; the indication information is obtained, and according to the indication information Generating pulsed pump light includes: receiving a synchronous optical signal; determining indication information according to the synchronous optical signal; wherein, the indication information indicates pulse time information of the quantum optical signal; generating pulsed pump light according to the indication information; wherein, the pulsed pump light The pulse time information of the is matched with the pulse time information of the quantum optical signal.

In specific implementation, the matching of the pulse time information of the pulsed pump light with the pulse time information of the quantum optical signal specifically means that one pulse of the pulsed pump light corresponds to a pulse of a quantum optical signal, and the corresponding pulse of the pulsed pump light There is an overlap region between the time taken and the time taken by the pulse of the quantum optical signal, and the overlap region is greater than the overlap region threshold. The duration occupied by the overlapping area is the duration when the time domain filtering device is in an on state when it is used as a switch. In another optional solution, the time taken by the pulse of the corresponding pulsed pump light completely coincides with the time taken by the pulse of the quantum optical signal. In this way, the pulse of each quantum optical signal can be obtained more accurately.

In practice, the quantum signal receiver can restore the original quantum secret key through the pulse of the quantum optical signal, while there are more classical optical signals or noise caused by other factors on other signals, if it enters the quantum signal receiver, it will cause the original The recovery rate of the quantum secret key decreases. In the prior art, the pulse of the quantum optical signal and the noise between the pulses of the quantum optical signal will enter the quantum signal receiver. The time domain filtering device provided by the embodiment of the present invention can realize extremely narrow filtering effect, this embodiment can greatly reduce the number of noise photons entering the quantum signal receiver, and improve the mixed transmission performance of the system. For example, the ability of a 100ps time-domain filtering device to suppress noise photons is 10 times that of a quantum detector in a 1ns gate-width quantum signal receiver.

In the embodiment of the present invention, the signal light is divided into the first signal light and the second signal light; pulse pump light is generated according to the instruction information; in the case of pulse pump light, the pulse pump light is used to control the first signal light The phase of the first phase modulation is performed, and the polarization of the first signal light after the first phase modulation is rotated by 90 degrees to obtain the first signal light with the first phase modulation and polarization rotation, and the pulsed pump light is used to The phase of the first signal light that undergoes the first phase modulation and the polarization rotation is subjected to the second phase modulation to obtain the first signal light that is the polarization rotation and the second phase modulation is performed, and the polarization is rotated and the second phase modulation is performed The first signal light without phase modulation and the second signal light without phase modulation are sent to the first port; in the absence of pulsed pump light, the first signal light without phase modulation and the second signal without phase modulation Light is sent to the second port. After the first phase modulation of the first signal light is performed by the pulse pump light, the polarization of the first signal light after the first phase modulation is rotated by 90 degrees, and then the second phase is performed by the pulse pump light. Modulation, so that the phase modulation of the first signal light is independent of the polarization of the pulsed pump light, so that the phase difference between the first signal light and the second signal light can be obtained more accurately.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings that need to be used in the description of the embodiments.

FIG. 1 is a schematic structural diagram of a time-domain filter optical switch provided by the prior art;

FIG. 2 is a schematic structural diagram of a time-domain filtering device provided by an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of another time-domain filtering device provided by an embodiment of the present invention;

FIG. 4 is a schematic structural diagram of another time-domain filtering device provided by an embodiment of the present invention;

FIG. 5 is a schematic structural diagram of another time-domain filtering device provided by an embodiment of the present invention;

FIG. 6 is a schematic structural diagram of another time-domain filtering device provided by an embodiment of the present invention;

7 is a schematic flow diagram of the signal light output from the coupling unit to the first Faraday rotating mirror unit and the second Faraday rotating mirror unit in the case of pulsed pump light in an embodiment of the present invention;

8 is a schematic flow diagram of the signal light output from the first Faraday rotating mirror unit and the second Faraday rotating mirror unit to the coupling unit in the case of pulsed pump light in an embodiment of the present invention;

9 is a schematic flow chart of the optical path transmission of the first signal light in the case of pulsed pump light in an embodiment of the present invention;

10 is a schematic flow diagram of the signal light output from the coupling unit to the first Faraday rotating mirror unit and the second Faraday rotating mirror unit under the condition that there is no pulsed pump light in the embodiment of the present invention;

Fig. 11 is a schematic flow diagram of the output of signal light from the first Faraday rotating mirror unit and the second Faraday rotating mirror unit to the coupling unit in the case of no pulsed pump light in the embodiment of the present invention;

Fig. 12 is a schematic structural diagram of a quantum communication system applying a time-domain filtering device provided by an embodiment of the present invention;

Fig. 13 is a schematic structural diagram of another quantum communication system applying a time-domain filtering device provided by an embodiment of the present invention;

FIG. 14 is a schematic structural diagram of a communication system applying a time-domain filtering device provided by an embodiment of the present invention;

FIG. 15 is a schematic diagram of the duration of a switch when a time-domain filtering device provided by an embodiment of the present invention is used as a switch;

FIG. 16 is a schematic flowchart of a time domain filtering method provided by an embodiment of the present invention.

Detailed ways

In order to make the object, technical solution and beneficial effects of the present invention more clear, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

FIG. 2 exemplarily shows a schematic structural diagram of a time-domain filtering device provided by an embodiment of the present invention. As shown in FIG. 2 , the time-domain filtering device 211 includes a coupling unit 213, and a processing unit 212 connected to the coupling unit 213; A pulsed pump light generating unit 214 connected to the processing unit 212 . The coupling unit 213 may include two ports, respectively a first port 226 and a second port 227 in FIG. 2 .

The coupling unit 213 is configured to receive the signal light, divide the signal light into the first signal light and the second signal light, and send the first signal light to the processing unit 212; after receiving the polarization rotation sent by the processing unit 212 and performing the second In the case of the second phase-modulated first signal light, the polarization-rotated and second-time phase-modulated first signal light and the second signal light without phase modulation are sent to the first port 226 of the coupling unit 213; When the first signal light without phase modulation sent by the processing unit 212 is received, the first signal light without phase modulation and the second signal light without phase modulation are sent to the second port 227 of the coupling unit. In an optional implementation, the first signal light whose polarization is rotated and subjected to the second phase modulation and the second signal light not subjected to phase modulation are interfered in the coupling unit 213, or it can also be referred to as coupling, Then output from the first port 226 of the coupling unit 213; the first signal light without phase modulation and the second signal light without phase modulation interfere in the coupling unit 213, or it can also be called as coupling, and then from the coupling The second port 227 output of unit 213.

Optionally, the coupling unit further includes a third port 228 and a fourth port 229; the coupling unit is configured to: receive signal light through the second port 227, and divide the signal light into first signal light and second signal light; The third port 228 sends the first signal light to the processing unit; sends the second signal light through the fourth port 229; receives the first signal light with polarization rotation and second phase modulation or no phase modulation through the third port 228 The first signal light; the second signal light without phase modulation is received through the fourth port 229; in the case of receiving the polarization rotation and the second phase modulation of the first signal light sent by the processing unit through the third port 228 Next, the polarization-rotated first signal light received through the third port 228 and the second phase-modulated second signal light received through the fourth port 229 without phase modulation are sent to the first signal light of the coupling unit. port 226; in the case of receiving the first signal light without phase modulation sent by the processing unit through the third port 228, the first signal light without phase modulation received through the third port 228 and the first signal light without phase modulation received through the third port 228 and passed through the fourth The second signal light without phase modulation received by the port 229 is sent to the second port 227 of the coupling unit.

Optionally, in the embodiment of the present invention, dividing the signal light into the first signal light and the second signal light specifically refers to dividing the signal light into the first signal light and the second signal light in terms of power. The coupling unit may be a 1×2 fiber coupler, or other optical devices capable of distributing or combining optical signal power among different optical fibers. Optionally, only the power of the signal light is distributed through the coupling unit, that is, the power of the first signal light and the second signal light can be the same or different, but other parameters of the first signal light and the second signal light are the same, For example, parameters such as wavelength, polarization, and phase are the same.

Optionally, the coupling unit 213 can be a coupler capable of two inputs and two outputs, which can split and combine the two optical signals, and according to the phase difference of the two received optical signals, the received After combining or interfering, the two optical signals are output from corresponding ports of the coupling unit 213, which may be, for example, a 3dB optical coupler.

Optionally, the coupling unit includes four ports, and the signal light can be received through the second port 227, and the signal light can also be received through the first port 226. In this embodiment of the present invention, only the second port 227 is used as an example for introduction. If the signal light is received through the first port 226, the time-domain filtering device can play a role of reflection, and the received signal light returns directly from the first port 226 without being modulated.

Optionally, the second signal light output from the fourth port 229 in the coupling unit may enter the fourth port 229 again. In an optional implementation, the second signal light is output from the fourth port 229 and enters the fourth port 229 again through a cycle. In another optional implementation, the second signal light is output from the fourth port 229 After being output, after certain processing, such as polarization rotation, attenuation, etc., it enters the fourth port 229 again. Regardless of the solution, the second signal light entering the fourth port 229 is the signal light without phase modulation . In Fig. 2, the fourth port 229 is connected to a ring, which is only an exemplary drawing. It simply describes that the second signal light has undergone certain processing or has not undergone certain processing to become the second signal without phase modulation described in this application. After the signal light, the second signal light without phase modulation is transmitted to the fourth port 229 again.

In the embodiment of the present invention, when the phase difference between the two received optical signals is determined to be zero by the coupling unit 213, the two optical signals are interfered and then output from the second port. Specifically, if the phase difference between the first signal light without phase modulation and the second signal light without phase modulation received by the coupling unit is zero, then the first signal light without phase modulation and the first signal light without phase modulation The phase-modulated second signal light is output from the second port 227 after interference.

In the embodiment of the present invention, when the coupling unit 213 determines that the phase difference between the two received optical signals is not zero and is a preset value, then the two optical signals after interference are sent from the first port 226 output. It can be divided into two cases, case a1, all the two optical signals after interference are output from the first port, or case a2, the two optical signals after interference are simultaneously output from the first port and the second port.

In the case of a1, the preset value is, for example, π, and the coupling unit 213 determines that the phase difference between the two optical signals is π, and then completely outputs the two optical signals through the first port after interference. That is to say, the phase difference between the phase-modulated first signal light with the first phase modulation and polarization rotation and the second signal light without phase modulation received by the coupling unit is π, then the phase-modulated The first signal light with the first phase modulation and polarization rotation and the second signal light without phase modulation are interfered and output from the first port 226 . In the embodiment of the present invention, optionally, in the embodiment of the present invention, the phase difference between the first signal light with the first phase modulation and polarization rotation after the phase modulation and the second signal light without phase modulation is π . That is to say, in the embodiment of the present invention, two phase modulations are performed on the first signal light, and the sum of the modulated phase changes of the two phase modulations is π.

Case a2, optionally, there is a phase difference between the first phase-modulated first signal light with polarization rotation and the second signal light without phase modulation received by the coupling unit, and the phase difference is 0 to π, the phase-modulated first signal light with the first phase modulation and polarization rotation and the second signal light without phase modulation are interfered, and output from the first port 226 and the second port 227 at the same time , the output ratio from the first port 226 to the second port 227 can be adjusted, for example, according to the difference between the first signal light with the first phase modulation and polarization rotation and the second signal light without phase modulation after phase modulation Phase difference adjustment.

In the embodiment of the present invention, the first signal light of the pulsed pump light has undergone two phase modulations successively. Since the optical path in the embodiment of the present invention is relatively short, the attenuation of the pulsed pump light during the two phase modulations can be ignored, and it can be considered The light intensity of the pulsed pump light is the same in the two phase modulation processes. Optionally, in the embodiment of the present invention, the amount of phase change of the first phase modulation performed by the pulse pump light on the phase of the first signal light can be adjusted by adjusting the light intensity of the pulse pump light.

The pulsed pump light generation unit 214 is configured to acquire indication information, generate pulsed pump light according to the indication information, and send the generated pulsed pump light to the processing unit 212 .

In the embodiment of the present invention, the pulsed pumping light generation unit 214 has multiple ways to obtain the indication information, such as determined by the information sent by the sender, or preset in advance, or preset rules in advance, and the indication determined according to the rules Information and the like are not limited in this embodiment of the present invention. The pulsed pumping light in the embodiment of the present invention is the pumping light in the form of pulses, that is to say, the pulsed pumping light is some pulses with intervals in time, and the specific information of a pulse in the pulsed pumping light can be obtained from the indication information Obtain information such as pulse duration, pulse pump light generation time, stop time, etc.

The processing unit 212 is configured to, in the case of receiving the pulse pump light sent by the pulse pump light generating unit 214, perform the first phase modulation on the phase of the first signal light by the pulse pump light, and perform the first phase modulation The polarization of the phase-modulated first signal light is rotated by 90 degrees to obtain the first signal light with the first phase modulation and polarization rotation, and the first signal light with the first phase modulation and polarization rotation is obtained by the pulse pump light The phase of the second phase modulation is performed to obtain the first signal light with polarization rotation and second phase modulation, and the first signal light with polarization rotation and second phase modulation is sent to the coupling unit 213; In the case of the pulsed pumping light sent from the pulsed pumping light generation unit, the first signal light not subjected to phase modulation is sent to the coupling unit 213 .

In the embodiment of the present invention, since the pulsed pumping light is some pulses with intervals in time, the processing unit 212 will receive the pulsed pumping light in a continuous time period, but will not receive it in the next continuous time period. Pulsed pump light is received. That is to say, in the embodiment of the present invention, when pulsed pump light is received, the first signal light with polarization rotation and second phase modulation and the second signal light without phase modulation will be output through the first port , in the embodiment of the present invention, when the pulsed pump light is not received, the first signal light with phase modulation and the second signal light without phase modulation are output through the second port, so that the embodiment of the present invention The switching function of the time domain filtering device can be realized by connecting the first port and the second port of the time domain filtering device to different devices.

Fig. 3 exemplarily shows a schematic structural diagram of another time-domain filtering device provided by an embodiment of the present invention. As shown in Fig. 3 , optionally, the processing unit 212 includes: a pulsed pump light generation unit 214 and a coupling unit 213 connected to the multiplexing/demultiplexing unit 223, the medium unit 222 connected to the multiplexing/demultiplexing unit 223, and the first Faraday rotating mirror unit 221 connected to the medium unit 222.

The multiplexing/demultiplexing unit 223 is configured to, in the case of receiving the pulsed pumping light sent by the pulsed pumping light generating unit 214, perform pulsed pumping light and the received first signal light sent by the coupling unit 213 Coupling to obtain the first coupled signal light; sending the first coupled signal light to the medium unit 222; demultiplexing the fourth coupled signal light to obtain the first signal light with polarization rotation and second phase modulation, and polarizing The first signal light rotated and phase-modulated for the second time is sent to the coupling unit 213 .

The medium unit 222 is used to make the pulsed pump light in the first coupled signal light perform the first phase modulation on the phase of the first signal light in the first coupled signal light in the medium unit 222 to obtain the first phase modulation The second coupled signal light coupled with the first signal light and the pulse pump light, and send the second coupled signal light to the first Faraday rotating mirror unit 221; make the pulse pump light in the third coupled signal light in the dielectric unit performing a second phase modulation on the phase of the first signal light that undergoes the first phase modulation and polarization rotation in the third coupled signal light to obtain the first signal light that undergoes the second phase modulation and polarization rotation and pulse pumping The optically coupled fourth coupled signal light is sent to the multiplexing/demultiplexing unit. There are various implementation schemes for the dielectric unit in the embodiment of the present invention, as long as the pulsed pump light can have a non-linear effect on the first signal light and the first signal light with the first phase modulation and polarization rotation in the dielectric unit, Therefore, it is enough to perform the second phase modulation on the phase of the first signal light and the phase of the first signal light that undergoes the first phase modulation and polarization rotation. For example, the medium unit can be a Kerr (Kerr) medium. Specifically, it can be Ordinary single-mode optical fiber, photonic crystal optical fiber, silicon wire waveguide, quantum dot and other media with third-order nonlinearity.

Optionally, in the embodiment of the present invention, the phase change amount of the first phase modulation of the first signal light by the pulsed pumping light can be adjusted by adjusting the light intensity of the pulsed pumping light. On the other hand, it can also be adjusted by adjusting It can be realized by parameters such as the material structure of the dielectric unit.

The first Faraday rotating mirror unit 221 is configured to rotate the polarization of the first signal light after the first phase modulation in the second coupled signal light by 90 degrees to obtain the first signal light with the first phase modulation and polarization rotation third coupled signal light coupled with the pulsed pump light; sending the third coupled signal light to the dielectric unit 222 .

The first Faraday rotating mirror unit 221 may include a Faraday rotating mirror, which may be mainly composed of permanent magnets, magneto-optical crystals and reflectors. For example, a 90-degree Faraday reflector provides a magnetic field to the magneto-optic crystal through a permanent magnet. When a beam passes by, the polarization of the beam will rotate 45 degrees under the magneto-optic effect. After being reflected by the mirror, it will pass through the magneto-optic crystal again and continue A 45-degree rotation ultimately rotates the incoming and outgoing light polarizations by 90 degrees.

In the embodiment of the present invention, the second coupled signal light enters the first Faraday rotator mirror unit 221, and the first Faraday rotator mirror unit only changes the polarization of the first signal light after the first phase modulation in the second coupled signal light Rotate, the polarization rotation in the embodiment of the present invention is rotated by 90 degrees means that the component in the horizontal direction (X-axis) is rotated to the vertical direction (Y-axis), and the component in the vertical direction (Y-axis) is rotated to the horizontal direction (X-axis). axis), such as deflection of 90 degrees, or deflection of 270 degrees, in short, it can be rotated by 90 degrees or an odd multiple of 90 degrees.

In the embodiment of the present invention, the first Faraday rotator does not rotate the polarization of the pulsed pump light in the second coupled signal light. Optionally, the rotation angle of the magneto-optic crystal in the first Faraday rotator mirror unit to the polarization of the first signal light in the embodiment of the present invention is related to the wavelength of the first signal light, which can be achieved by selecting a specific magneto-optic crystal and pulse The wavelength of the pump light makes the entire first Faraday rotator mirror unit not rotate the polarization of the pulse pump light, but only acts as an ordinary reflector, and the reflected pulse pump light will continue to rotate 90 degrees with the polarization. The first signal light passes through the dielectric unit, so that a nonlinear interaction occurs, and optionally the intensity of the nonlinear phase shift has a linear relationship with the intensity of the pulsed pumping light.

For example, the wavelength range of the pulsed pump light and the wavelength range of the first signal light are set to two wavelength ranges far away, and the parameters of the first Faraday rotating mirror unit are specifically set, so as to realize only the The purpose of rotating the polarization of the first signal light after the first phase modulation in the received second coupled signal light and not rotating the polarization of the pulsed pump light in the second coupled signal light.

Based on this, the multiplexing/demultiplexing unit 223 in the embodiment of the present invention may be a wavelength division multiplexing/demultiplexing device, that is, a wavelength-related coupler. On the one hand, the wavelength division multiplexer/demultiplexer can combine the optical signals output by multiple transmitters with different wavelengths and input them into one optical fiber; on the other hand, it can combine multiple optical signals output by one optical fiber Optical signal, separated out. Specifically, the multiplexing/demultiplexing unit 223 can couple the received first signal light and pulsed pumping light into an optical fiber, and output it to the medium unit through the optical fiber. The pulsed pump light included in the second interference signal light output by the dielectric unit and the first signal light with polarization rotation and second phase modulation are separated, and the polarization rotation and second phase modulation are separated through the port The first signal light is sent to the coupling unit 213, and the separated pulsed pump light is output through another port.

Optionally, the multiplexing/demultiplexing unit 223 is further configured to: pass the received first signal light sent by the coupling unit through the The medium unit is sent to the first Faraday rotating mirror unit; the first Faraday rotating mirror unit 221 is used to rotate the polarization of the received first signal light by 90 degrees to obtain the first signal light without phase modulation; The modulated first signal light is sent to the coupling unit through the medium unit and the multiplexing/demultiplexing unit in sequence.

That is to say, in the embodiment of the present invention, when the pulsed pumping light generation unit 214 does not generate the pulsed pumping light, the first signal light split by the coupling unit 213 passes through the multiplexing/demultiplexing unit 223 and the After the medium unit 222 reaches the first Faraday rotator mirror unit 221, the phase of the first signal light will not be modulated, so the phase of the first signal light does not change, and the polarization of the first signal light is in the first Faraday rotator mirror unit 221 After being deflected by 90 degrees, the polarization is then rotated by 90 degrees, and the first signal light without phase modulation returns to the coupling unit 213 through the dielectric unit 222 and the multiplexing/demultiplexing unit 223 in sequence. The coupling unit 213 outputs the first signal light without phase modulation and the second signal light without phase modulation through the second port 227 .

In the above content, based on the content shown in FIG. 2 and FIG. 3 , the second optical signal output by the coupling unit 213 has not undergone phase modulation, and optionally, it may directly return to the coupling unit without undergoing other processing. 213 , so as to implement coupling with the first signal light that is not phase-modulated or with the first signal light that is phase-modulated and undergoes the first phase modulation and polarization rotation, as shown in FIG. 2 and FIG. 3 . Optionally, in FIG. 2 and FIG. 3 , the polarization of the first signal light that has been rotated and phase-modulated for the second time can be rotated again by 90 degrees, so that the coupling unit 213 realizes the second signal light without phase modulation. Coupling with the first signal light without phase modulation, or realizing the coupling between the second signal light without phase modulation and the first phase modulation and polarization-rotated first signal light with phase modulation .

Further, in order to keep the two paths of signal light reaching the coupling unit 213 in the same polarization state, a second Faraday rotator mirror unit may be correspondingly arranged on the optical path of the second signal light. FIG. 4 exemplarily shows a schematic structural diagram of another time-domain filtering device provided by an embodiment of the present invention. As shown in FIG. 4 , the time-domain filtering device further includes a second Faraday rotating mirror unit 224 connected to the coupling unit 213 .

The second Faraday rotating mirror unit 224 is used to receive the second signal light sent by the coupling unit, rotate the polarization of the second signal light by 90 degrees to obtain the second signal light without phase modulation, and convert the second signal light without phase modulation The second signal light is sent to the coupling unit.

In this embodiment, optionally, the polarization of the second signal light can be rotated by 90 degrees through the second Faraday rotating mirror unit 224, the polarization of the second signal light after polarization rotation, and the second signal without phase modulation The polarization of the light is the same as that of the first signal light not subjected to phase modulation received by the coupling unit 213 and the first signal light subjected to phase modulation and subjected to first phase modulation and polarization rotation.

The second Faraday rotating mirror unit 224 may include a Faraday rotating mirror, which may be mainly composed of permanent magnets, magneto-optical crystals and reflectors. For example, a 90-degree Faraday reflector provides a magnetic field to the magneto-optic crystal through a permanent magnet. When a beam passes by, the polarization of the beam will rotate 45 degrees under the magneto-optic effect. After being reflected by the mirror, it will pass through the magneto-optic crystal again and continue A 45-degree rotation ultimately rotates the incoming and outgoing light polarizations by 90 degrees.

Correspondingly, the coupling unit 213 is configured to, in the case of receiving the first signal light with polarization rotation and second phase modulation sent by the processing unit, convert the first signal light with polarization rotation and second phase modulation to The second signal light without phase modulation is sent to the first port of the coupling unit; in the case of receiving the first signal light without phase modulation sent by the processing unit, the first signal light without phase modulation and without The phase-modulated second signal light is sent to the second port of the coupling unit.

In order to make the light intensity of the two optical signals received by the coupling unit 213 basically the same, an attenuation unit 225 is set on the optical path of the second optical signal, so that the losses of the left and right channels are the same, and then complete interference occurs at the coupling unit 213 . Fig. 5 exemplarily shows a schematic structural diagram of another time-domain filtering device provided by an embodiment of the present invention. As shown in Fig. 5 , the time-domain filtering device further includes: an attenuation unit 225 connected to the coupling unit 213, and an attenuation unit 225 connected to the second Faraday rotating mirror unit 224.

Optionally, the attenuation unit is configured to receive the second signal light sent by the coupling unit, attenuate the second signal light for the first time to obtain the second signal light after the first attenuation, and attenuate the second signal light after the first attenuation sending the light to the second Faraday rotator mirror unit; receiving the first attenuation and polarization-rotated second signal light sent by the second Faraday rotator mirror unit, attenuating the first attenuation and polarization-rotated second signal light, The second signal light without phase modulation is obtained, and the second signal light without phase modulation is sent to the coupling unit. Optionally, the attenuation unit can be an adjustable optical attenuator, which is used to attenuate the optical power of the signal light on the optical path of the second signal light, and the attenuation degree can be adjusted according to actual needs. After the attenuation unit 225 attenuates the signal on the optical path of the second signal light, the optical powers of the two optical signals received by the coupling unit 213 are basically the same.

Optionally, correspondingly, the second Faraday rotating mirror unit is used to receive the second signal light after the first attenuation sent by the attenuation unit, and rotate the polarization of the second signal light after the first attenuation by 90 degrees to obtain the second signal light after the first attenuation. The first attenuation and polarization-rotated second signal light is sent to the attenuation unit.

Optionally, the corresponding coupling unit is configured to rotate the polarization and perform the second phase modulation of the first signal light sent by the processing unit in the case of receiving the first signal light of the polarization rotation and the second phase modulation The light and the second signal light without phase modulation are sent to the first port of the coupling unit; in the case of receiving the first signal light without phase modulation sent by the processing unit, the first signal light without phase modulation and the second signal light without phase modulation are sent to the second port of the coupling unit. In an optional implementation, the first signal light with polarization rotation and second phase modulation and the second signal light without phase modulation interfere in the coupling unit 213, and then the first signal light from the coupling unit 213 Port 226 output; the first signal light without phase modulation and the second signal light without phase modulation interfere in the coupling unit 213, or it can also be referred to as coupling, and then output from the second port 227 of the coupling unit 213 .

Fig. 6 exemplarily shows a schematic structural diagram of another time-domain filtering device provided by an embodiment of the present invention. As shown in Fig. 6 , a The optical circulator 231 is connected to the optical circulator 232 on the second port 227 .

The function of any optical circulator in the optical circulator 231 and the optical circulator 232 is that when light is incident from a certain port, it only allows the light to transmit in a specific direction, and prevents the light from transmitting in other directions, especially the reverse direction. Specifically, the optical circulator 231 includes a port S1, a port S2 and a port S3. The pulsed pumping light enters from port S1 and can only be output from port S2; if it enters from port S2, it can only be output from port S3. Optical circulator 232 includes port S4, port S5, and port S6. If the signal light enters through port S4, it can only be output through port S5; if it enters through port S5, it can only be output through port S6.

Fig. 7 exemplarily shows a schematic flow diagram of the signal light output from the coupling unit to the first Faraday rotator mirror unit and the second Faraday rotator mirror unit in the case of pulsed pump light in the embodiment of the present invention, and Fig. 8 exemplarily shows In the embodiment of the present invention, there is a schematic flow diagram of the signal light output from the first Faraday rotator mirror unit and the second Faraday rotator mirror unit to the coupling unit under the condition of pulsed pump light. FIG. 9 schematically shows the Schematic flow chart of the optical path transmission of the first signal light in the case of pulsed pump light. An example provided by the embodiment of the present invention will be introduced below with reference to FIG. 7 , FIG. 8 and FIG. 9 .

As shown in FIG. 7 , the coupling unit 213 divides the signal light into the first signal light and the second signal light, sends the first signal light to the multiplexing/demultiplexing unit 223, and sends the second signal light to the attenuation unit 225 .

In case b1, when there is pulsed pump light, the optical path transmission process corresponding to the second signal light:

The attenuation unit 225 is configured to receive the second signal light sent by the coupling unit, attenuate the second signal light for the first time to obtain the second signal light after the first attenuation, and send the second signal light after the first attenuation to The second Faraday rotating mirror unit 224 . The second Faraday rotating mirror unit 224 rotates the polarization of the second signal light after the first attenuation by 90 degrees to obtain the second signal light that undergoes the first attenuation and polarization rotation, and performs the first attenuation and polarization rotation The second signal light is sent to the attenuation unit. As shown in FIG. 8 , the attenuation unit 225 then attenuates the second signal light that undergoes first attenuation and polarization rotation to obtain the second signal light without phase modulation, and sends the second signal light without phase modulation to coupling unit.

In case b2, when there is pulsed pump light, the optical path transmission process corresponding to the first signal light:

The pulsed pump light generating unit 214 sends the generated pulsed pump light to the multiplexing/demultiplexing unit 223 .

The multiplexing/demultiplexing unit 223, in the case of receiving the pulsed pumping light sent by the pulsed pumping light generating unit, couples the pulsed pumping light and the first signal light to obtain the first coupled signal light; A coupled signal light is sent to the dielectric unit 222 .

The dielectric unit 222 is configured to make the pulsed pump light in the first coupled signal light perform the first phase modulation on the phase of the first signal light in the first coupled signal light in the dielectric unit, so as to obtain the first phase modulated The second coupled signal light coupled with the first signal light and the pulsed pump light is sent to the first Faraday rotating mirror unit 221 .

The first Faraday rotating mirror unit 221 is configured to rotate the polarization of the first signal light after the first phase modulation in the second coupled signal light by 90 degrees to obtain the first signal light with the first phase modulation and polarization rotation A third coupled signal light coupled with the pulsed pump light. As shown in FIG. 8 , the third coupled signal light is sent to the medium unit 222 .

The dielectric unit 222 is used to make the pulsed pump light in the third coupled signal light perform a second phase modulation on the phase of the first signal light that undergoes first phase modulation and polarization rotation in the third coupled signal light in the dielectric unit , and the pulsed pump light has a nonlinear effect on the first signal light with the first phase modulation and polarization rotation in the dielectric unit, and the first signal light and pulse pump light with the second phase modulation and polarization rotation are obtained the coupled fourth coupled signal light, and send the fourth coupled signal light to the multiplexing/demultiplexing unit 223;

The multiplexing/demultiplexing unit 223 demultiplexes the fourth coupled signal light to obtain the first signal light with polarization rotation and second phase modulation, and the first signal light with polarization rotation and second phase modulation sent to the coupling unit 213. The demultiplexed pulse pump light is sent out from another port, for example, in FIG. 6 , the demultiplexed pulse pump light is sent out from port S3 of the optical circulator 231 .

The coupling unit 213, when receiving the first signal light with polarization rotation and second phase modulation sent by the processing unit, combines the first signal light with polarization rotation and second phase modulation with the first signal light without phase modulation The second signal light is sent to the first port 226 of the coupling unit.

As shown in Figure 9, the multiplexing/demultiplexing unit 223 receives the first signal light, the component of the first signal light on the X axis is Xa, the component of the first signal light on the Y axis is Ya, and the absolute value of Ya can be Greater than, equal to or less than the absolute value of Xa. The multiplexing/demultiplexing unit 223 receives the pulsed pumping light, the component of the pulsed pumping light on the X axis is Xb, the component of the pulsed pumping light on the Y axis is Yb, and the absolute value of Yb can be greater than, equal to or smaller than Xb the absolute value of . The multiplexing/demultiplexing unit 223 multiplexes the first signal light and the pulsed pumping light and inputs them to the value medium unit 222 . Ya is modulated by Yb, and Xa is modulated by Xb. Then enter into the first Faraday rotating mirror unit 221 . In the first Faraday rotator mirror unit 221, the polarization of Xa modulated by Xb is rotated by 90 degrees to become a component on the Y axis, and the polarization of Ya modulated by Yb is rotated by 90 degrees to become a component on the X axis. The polarization of the pulsed pump light is not deflected, so the component on the X axis is still Xb, and the component on the Y axis is still Yb. After the polarization is rotated, it enters the dielectric unit 222. Xa modulated by Xb is the component on the Y axis, and it is modulated by the Y-axis component Yb of the pulsed pump light nonlinearly. Ya, modulated by Yb, is the component on the X axis. The component of is subjected to the nonlinear modulation of the X-axis component Xb of the pulsed pump light, and then input into the multiplexing/demultiplexing unit 223 to be demultiplexed and output. The obtained Y-axis component of the first signal light with polarization rotation and second phase modulation is Xa modulated by Xb and Yb in sequence, and the obtained X-axis component of the first signal light with polarization rotation and second phase modulation It is Ya modulated by Yb and Xb in turn. That is to say, the X-axis and Y-axis components of the first signal light are both modulated by Xb and Yb, thereby ensuring that the phase modulation changes of the X-axis and Y-axis components of the first signal light are the same, thereby ensuring The amount of phase modulation variation of the first signal light is not affected by the polarization of the first signal light and/or the polarization of the pulsed pump light.

That is to say, in the embodiment of the present invention, regardless of the polarization of the incident pulsed pump light and the first signal light, the nonlinearity of the forward incident light of the first signal light and the reflected light of the first Faraday rotator mirror unit The phase shift is a complementary process. It is only necessary to ensure that the sum of the nonlinear phase shifts of the first signal light in the forward direction and reflection is a preset value, such as π, to achieve the first signal light and the phase modulation without phase modulation. The purpose of the output of the second signal light from the first port can be seen that in the embodiment of the present invention, under the action of the first Faraday rotating mirror unit, various polarization effects of the optical device and the optical path, such as birefringence, optical rotation and total reflection, are all eliminated. Offset, the time-domain filtering device of the embodiment of the present invention achieves the goal of being independent of polarization.

Fig. 10 exemplarily shows the schematic flow diagram of the signal light output from the coupling unit to the first Faraday rotator mirror unit and the second Faraday rotator mirror unit under the condition that there is no pulsed pump light in the embodiment of the present invention, and Fig. 11 exemplarily shows A schematic flow chart of the output of signal light from the first Faraday rotator mirror unit and the second Faraday rotator mirror unit to the coupling unit in the case of no pulsed pump light in the embodiment of the present invention is shown. An example provided by the embodiment of the present invention will be introduced below with reference to FIG. 10 and FIG. 11 .

As shown in FIG. 10 , the coupling unit 213 divides the signal light into the first signal light and the second signal light, sends the first signal light to the multiplexing/demultiplexing unit 223, and sends the second signal light to the attenuation unit 225 .

In case c1, when there is no pulsed pump light, the optical path transmission process corresponding to the second signal light is the same as that in the above case b1 with pulsed pump light, and the optical path transmission process corresponding to the second signal light is not repeated here. .

In case c2, in the absence of pulsed pump light, the optical path transmission process corresponding to the first signal light:

The multiplexing/demultiplexing unit 223 sends the received first signal light to the first Faraday rotating mirror unit 221 through the medium unit 222 when the pulsed pumping light sent by the pulsed pumping light generating unit is not received . Since there is no pulsed pumping light, the phase of the first signal light is not modulated by the pulsed pumping light in this case.

The first Faraday rotating mirror unit 221 rotates the polarization of the first signal light by 90 degrees to obtain the first signal light without phase modulation; the first signal light without phase modulation passes through the medium unit 222 and the multiplexing/demultiplexing in sequence The multiplexing unit 223 sends to the coupling unit 213 .

When the coupling unit 213 receives the first signal light without phase modulation, it sends the first signal light without phase modulation and the second signal light without phase modulation to the second port 227 of the coupling unit. Optionally, as shown in FIG. 6, the coupling unit 213 sends the first signal light without phase modulation and the second signal light without phase modulation to the port S5 of the optical circulator 232 through the second port 227, and the slave port S6 output.

The time-domain filtering device 211 provided by the embodiment of the present invention can be applied to various scenarios, such as the transmission scenario of quantum optical signals. Figure 12 exemplarily shows a quantum communication using the time-domain filtering device provided by the embodiment of the present invention A schematic structural diagram of the system, FIG. 13 exemplarily shows a schematic structural schematic diagram of another quantum communication system applying a time-domain filtering device provided by an embodiment of the present invention.

Optionally, the signal light is a quantum optical signal, the first signal light is a first quantum optical signal, and the second signal light is a second quantum optical signal; the first port is connected to a quantum optical signal receiver; the pulse pumping light generation unit, Used for: receiving synchronous optical signals; determining indication information according to synchronous optical signals; wherein, the indication information indicates the pulse time information of the quantum optical signal; generating pulsed pump light according to the indication information; wherein, the pulse time information of the pulsed pump light Matching with the pulse time information of the quantum optical signal.

In specific implementation, the matching of the pulse time information of the pulsed pump light with the pulse time information of the quantum optical signal specifically means that one pulse of the pulsed pump light corresponds to a pulse of a quantum optical signal, and the corresponding pulse of the pulsed pump light There is an overlap region between the time taken and the time taken by the pulse of the quantum optical signal, and the overlap region is greater than the overlap region threshold. The duration occupied by the overlapping area is the duration when the time domain filtering device is in an on state when it is used as a switch. In another optional solution, the time taken by the pulse of the corresponding pulsed pump light completely coincides with the time taken by the pulse of the quantum optical signal. In this way, the pulse of each quantum optical signal can be obtained more accurately. A detailed example is given below to illustrate.

As shown in Figure 12, in the embodiment of the present invention, the sending end includes a classical signal transmitter 201, a synchronous signal transmitter 202, and a quantum signal transmitter 203, and the classical optical signal and the synchronous signal transmitter 202 sent by the classical signal transmitter 201 The synchronous optical signal sent out and the quantum optical signal sent out by the quantum signal transmitter 203 are sent to the receiving end through the wavelength division multiplexing unit 204 . Other multiplexing methods can also be used. In the embodiment of the present invention, WDM service is used as an example for introduction.

The receiving end restores the received signal to a classical optical signal, a synchronous optical signal and a quantum optical signal through the WDM unit 205, or through other multiplexing methods. In this embodiment of the present invention, only WDM is used as an example. The classical optical signal is sent to the classical signal receiver 206, and the synchronous optical signal is optionally divided into a first synchronous optical signal and a second synchronous optical signal by an optical beam splitter 209. Optionally, the optical beam splitter 209 is only for synchronous optical The power of the signal is divided, that is to say, the power of the first synchronous optical signal and the second synchronous optical signal are the same or different, and other parameters such as the wavelength of the first synchronous optical signal and the second synchronous optical signal are the same. The optical beam splitter 209 may be a 1×2 fiber coupler, or other optical devices capable of distributing or combining optical signal power among different optical fibers. Optionally, only the power of the synchronous optical signal is distributed through the optical beam splitter, that is, the power of the first synchronous optical signal and the second synchronous optical signal can be the same or different, but the first synchronous optical signal and the second synchronous optical signal Other parameters of the signal are the same, such as wavelength, polarization, phase and other parameters are the same. The quantum optical signal becomes signal light, is input into the port S4 of the optical circulator 232, and enters the coupling unit 213 through the port S5.

The second synchronous optical signal enters the pulsed pumping light generating unit 214 for generating the pulsed pumping light signal. The pulse information of the quantum optical signal is recorded in the synchronous optical signal, that is to say, the quantum optical signal is also a pulse. The second synchronous optical signal separated from the synchronous optical signal can determine the pulse information of the quantum optical signal, such as when it arrives Receiver and so on. An optional implementation is to generate new strong light as pulsed pump light according to the instruction information, and another implementation is to process the second synchronous optical signal, for example, amplify it through an amplifier, so as to obtain pulsed pump light.

Optionally, the first port 226 of the coupling unit 213 is connected to the quantum signal receiver 208 . That is to say, in the embodiment of the present invention, when the quantum optical signal pulse is not received, the pulsed pump light is not generated, so that the quantum optical signal sent by the quantum signal transmitter is output through the second port, such as output through port S6 out, discard this part of the optical signal. Only when the quantum optical signal pulse is received, the pulse of the pulsed pump light is correspondingly generated, so that the quantum optical signal pulse is input into the quantum signal receiver 208 through the second port. It can be seen that the time domain filtering device is generating the pulse In the case of pump light, the function of opening the switch is realized, and the pulse of the quantum optical signal is successfully input to the quantum signal receiver. The received optical signal will be input to the quantum signal receiver.

In practice, the quantum signal receiver can restore the original quantum secret key through the pulse of the quantum optical signal, while there are more classical optical signals or noise caused by other factors on other signals, if it enters the quantum signal receiver, it will cause the original The recovery rate of the quantum secret key decreases. In the prior art, the pulse of the quantum optical signal and the noise between the pulses of the quantum optical signal will enter the quantum signal receiver. The time domain filtering device provided by the embodiment of the present invention can realize extremely narrow filtering effect, this embodiment can greatly reduce the number of noise photons entering the quantum signal receiver, and improve the mixed transmission performance of the system. For example, a 100 picosecond (ps) time-domain filter is 10 times more capable of suppressing noise photons than a quantum detector in a 1 nanosecond (ns) gate width quantum signal receiver.

Optionally, since the mixed-transmission system only needs to receive quantum signals, the optical circulator in this solution can be replaced or omitted by an isolator, which will reduce the loss of quantum signals in the system.

As shown in FIG. 13 , in the embodiment of the present invention, the quantum optical signal can be obtained by combining multiple sub-quantum optical signals such as the sub-quantum optical signal 241 and the sub-quantum optical signal 242 at the sending end through the multiplexer 246 . At the receiving end, the first port of the coupling unit 213 can be connected to the splitter 245, and the received quantum optical signal pulse can be divided into multiple sub-quantum optical signals, such as the sub-quantum optical signal 243 and the sub-quantum optical signal 244, so as to separate Probing.

In addition to the above introduction, the time-domain filtering device in the embodiment of the present invention can also be applied to FDDI, optical node bypass, loop test sensing system, etc., and can also be used in combination with other types of optical switches, so that the time-domain filtering device The composed switch system is more perfect and more flexible. Fig. 14 exemplarily shows a schematic structural diagram of a communication system applying a time-domain filtering device provided by an embodiment of the present invention. As shown in Fig. 14, the communication system includes two time-domain filtering devices, and the time-domain filtering at the sending end The device 211 and the time-domain filtering device 271 at the receiving end, the time-domain filtering device 211 can also be applied to the receiving end, and this embodiment of the present invention is only an example.

In case d1, the signal light is sent from the transmission device 261 to the transmission device 262 .

When there is no pump pulse input, the signal light is input from the port S4, output through the port S5 of the optical circulator 232, then enters the time-domain filtering device 211, returns to the original path, is output from the second port 227, and enters the optical circulator 232 again , is output from the port S6 of the optical circulator 232, transmitted from the main path to the port S15 of the optical circulator 293, and enters the transmission device 262 through its port S14.

When the main road has business or fails, the signal light can also be transmitted from the backup road. Specifically, the signal light passes through a 1:2 coupler at the end of the transmission device 261, and the signal light is divided into two, one of which is transmitted to the transmission device 262, and the other is used as a trigger signal for the pump pulse, so that the time domain filtering device 211 Produce pulsed pump light.

When there is a pump pulse input, the signal light is input from the port S4, output through the port S5 of the optical circulator 232, then enters the time domain filtering device 211, and is output from the first port 226, and is input through the port S7 of the optical circulator 251, Output from the port S8, output to the port S10 of the optical circulator 292 through the backup path, and output to the transmission device 262 through the port S12.

In case d2, the signal light is sent from the transmission device 262 to the transmission device 261 .

When there is no pump pulse input, the signal light is input from the port S14 of the optical circulator 293, enters the time-domain filtering device 271 through the port S13 of the optical circulator 293, and then enters the second port 287, and then returns through the original path and passes through the second port 287 output, enter the optical circulator 293 again, output from the port S15 of the optical circulator 293, transmit from the main road to the port S6 of the optical circulator 232, and enter the transmission device 261 through its port S4.

Specifically, the signal light passes through the 1:2 coupler at the end of the transmission device 262, and the signal light is divided into two, one of which is transmitted to the transmission device 261, and the other is used as a trigger signal for the pump pulse, so that the time domain filter device 271 Produce pulsed pump light.

When there is a pump pulse input, the signal light is input from the port S14 of the optical circulator 293, output through the port S13 port of the optical circulator 293, and then enters the time domain filtering device 271 and is output to the optical circulator 292 from the first port 286 The port S11 of the optical circulator 251 is output from the port S10, and output to the port S8 of the optical circulator 251 through the backup path, and output to the transmission device 261 through the port S9.

Based on the above-mentioned time-domain filtering devices shown in FIGS. 2 to 14 , FIG. 15 exemplarily shows a schematic diagram of the duration of switching on when a time-domain filtering device provided by an embodiment of the present invention is used as a switch, as shown in FIG. 15 , since the time-domain filtering device has nothing to do with polarization, it can be assumed that the polarization of the pulsed pump light is the same as that of the signal light. In the case of different polarizations, the following analysis is also true. The above-mentioned dielectric unit in Figures 2 to 4 can be set as a Kerr medium, such as a common single-mode fiber with third-order nonlinearity, assuming that the speed of the pulsed pump light is slower than that of the signal light, and the optical path of the beam back and forth is L, That is to say, the journey of the first signal light from the multiplexing/demultiplexing unit to the multiplexing/demultiplexing unit is L, and the pulse width of the pulsed pumping light is t _p . The pulse of the pulse pump light and the pulse of the first signal light are multiplexed/demultiplexed at the same time, but because the pulse speed of the first signal light is fast, after the pulse of the first signal light reaches the end, the pulse pump light The trailing edge of the pulse of the first signal light will be aligned with the position of t _p +t of the pulse of the first signal light, where t is the leading time of the pulse of the first signal light than the pulse of the pulsed pump light, which can be expressed by the following formula (1) :

In the formula (1), L is the journey of the first signal light from the multiplexing/demultiplexing unit to the multiplexing/demultiplexing unit; t is the pulse ratio of the first signal light to the pulse of the pumping light Leading time; V _p is the speed of the pulsed pump light; V _s is the speed of the first signal light.

It can be seen from Fig. 15 that within the entire pulse width t _s of the pulse of the first signal light, only the first signal light within the time period _tp + t will interact with the pulsed pump light, and this interaction will introduce a preset The phase difference, such as a nonlinear phase shift of π, will come out of the first port after interfering with the second signal light not subjected to phase modulation. The other part of the pulse of the first signal light does not undergo nonlinear phase shift with the pulsed pumping light, so it will come out from the second port after interfering with the second signal light without phase modulation. Therefore, in the end, when the entire time-domain filtering device is used as a switch, the switching duration is t _p +t.

It can be seen that in the embodiment of the present invention, by adjusting the pulse width of the pulsed pump light, the length of the optical fiber, and selecting different wavelengths of the first signal light and the pulsed pump light, the control of the switching duration of the time domain filter device can be realized. . For example, when the pulsed pump light is 1550 nanometers (nm), the pulse width is 50 ps, and the first signal light is 1310 nm, then Picoseconds per meter (ps/m), when the optical distance L=25m, it can generate a switching time of 100ps for the signal light.

Similarly, if the propagation speed of the pulsed pump light is faster than that of the first signal light, the final switching duration of the entire time-domain filter device is t _s +t', which can be expressed by the following formula (2):

In the formula (2), L is the journey of the first signal light from the multiplexing/demultiplexing unit to the return to the multiplexing/demultiplexing unit; t′ is the leading time of the pulsed pumping light than the first signal light; V _p is the speed of the pulsed pump light; V _s is the speed of the first signal light.

In the embodiment of the present invention, optionally, in order to reduce the length L of the optical fiber and make the system more stable, the pulsed pumping light and the first signal light need to have a relatively large speed difference, which means that the pulsed pumping light is required to The distance between the wavelength and the wavelength of the first signal light is large, which can reduce the interference of the pulsed pump light on the first signal light, so that the impact of the noise photons generated by the pulsed pump light on the first signal light is minimized. In addition, optionally, the structure of the dielectric unit can also be designed according to requirements to achieve specific functions, such as increasing the third-order nonlinearity of the structure, increasing or reducing the speed difference between the pump light and the signal light, and reducing the speed of the system. nonlinear noise etc.

From the above, it can be seen that the embodiments of the present invention achieve the same effect as the pulsed pumping light and the second signal light through the equi-arm Michelson interferometer equipped with a Faraday rotating mirror and the non-linear phase shift generated by the pulsed pumping light on the cross-phase modulation of the first signal light. An extremely narrow time-domain filter device in which signal light is polarization-independent, and is a low-cost, low-loss device. At the same time, based on this device, it is proposed to perform time-domain filtering on the co-fiber mixed transmission system of quantum signals and classical signals, which equivalently shortens the gate width of single photon detectors, reduces the influence of noise photons on the system, and improves the mixed transmission performance of the system.

Fig. 16 exemplarily shows a schematic flowchart of a time domain filtering method.

Based on the same idea, an embodiment of the present invention provides a schematic flowchart of a time domain filtering method, as shown in FIG. 16 , the time domain filtering method includes:

Step 1601, receiving signal light, and dividing the signal light into first signal light and second signal light;

Step 1602, acquire instruction information, and generate pulse pump light according to the instruction information; if there is pulse pump light, perform step 1603; if there is no pulse pump light, perform step 1604;

Step 1603: Perform the first phase modulation on the phase of the first signal light with the pulsed pump light, and rotate the polarization of the first signal light after the first phase modulation by 90 degrees to obtain the first phase modulation and polarization The rotated first signal light performs a second phase modulation on the phase of the first signal light that undergoes the first phase modulation and polarization rotation through the pulsed pump light, and obtains the first signal that has the polarization rotation and undergoes the second phase modulation light, and sending the first signal light with polarization rotation and second phase modulation and the second signal light without phase modulation to the first port;

Step 1604: Send the first signal light without phase modulation and the second signal light without phase modulation to the second port.

In an optional solution, the signal light is received through the second port of the coupling unit in the above embodiment, and the signal light is divided into the first signal light and the second signal light, and then the polarization is rotated and the second The first signal light without phase modulation and the second signal light without phase modulation are sent to the first port of the coupling unit, and the first signal light without phase modulation and the second signal light without phase modulation are sent to the coupling unit the second port.

Optionally, receiving the signal light and dividing the signal light into the first signal light and the second signal light includes: receiving the signal light through the second port; dividing the signal light into the first signal light and the second signal light; The third port sends the first signal light, and the fourth port sends the second signal light; the first signal light with polarization rotation and second phase modulation and the second signal light without phase modulation are sent to the first port, The method includes: sending the first signal light received through the third port with polarization rotation and second phase modulation and the second signal light received through the fourth port without phase modulation to the first port of the coupling unit; Sending the first signal light without phase modulation and the second signal light without phase modulation to the second port includes: receiving the first signal light without phase modulation received through the third port and the first signal light without phase modulation through the fourth port The received second signal light without phase modulation is sent to the second port of the coupling unit.

Optionally, in the case of pulsed pump light, the first phase modulation is performed on the phase of the first signal light by the pulsed pump light, and the polarization of the first signal light after the first phase modulation is rotated by 90 degrees, the first signal light that undergoes the first phase modulation and polarization rotation is obtained, and the second phase modulation is performed on the phase of the first signal light that undergoes the first phase modulation and polarization rotation through the pulsed pump light to obtain the polarization rotation And the first signal light for the second phase modulation includes: in the case of pulsed pump light, coupling the pulsed pump light and the first signal light to obtain the first coupled signal light; combining the first coupled signal The light is sent to the medium unit, and the phase of the first signal light in the first coupled signal light is phase-modulated for the first time in the medium unit through the pulsed pump light in the first coupled signal light, and the phase modulation of the first time is obtained. The second coupled signal light coupled with the first signal light and the pulsed pump light; the polarization of the first signal light after the first phase modulation in the second coupled signal light is rotated by 90 degrees to obtain the first phase modulation and The third coupled signal light coupled with the polarization-rotated first signal light and the pulsed pump light; the third coupled signal light is sent to the dielectric unit, and the pulsed pump light in the third coupled signal light is coupled to the third coupled signal light in the dielectric unit In the signal light, the phase of the first signal light that undergoes the first phase modulation and polarization rotation is subjected to the second phase modulation, and the first signal light that undergoes the second phase modulation and polarization rotation is coupled with the pulsed pumping light. Four coupled signal lights; demultiplexing the fourth coupled signal light to obtain the first signal light with polarization rotation and second phase modulation.

Optionally, in the absence of pulse pump light, before sending the first signal light without phase modulation and the second signal light without phase modulation to the second port, further comprising: In the case of , the polarization of the first signal light is rotated by 90 degrees to obtain the first signal light without phase modulation.

Optionally, sending the first signal light with polarization rotation and second phase modulation and the second signal light without phase modulation to the first port includes: rotating the polarization of the second signal light by 90 degrees to obtain The second signal light without phase modulation; the first signal light with polarization rotation and second phase modulation and the second signal light without phase modulation are sent to the first port; the first signal without phase modulation Sending the light and the second signal light without phase modulation to the second port includes: rotating the polarization of the second signal light by 90 degrees to obtain the second signal light without phase modulation; The signal light and the second signal light without phase modulation are sent to the second port.

Optionally, sending the first signal light with polarization rotation and second phase modulation and the second signal light without phase modulation to the first port includes: attenuating the second signal light for the first time to obtain the second signal light The second signal light after attenuation once; the polarization of the second signal light after the first attenuation is rotated by 90 degrees to obtain the second signal light with the first attenuation and polarization rotation; the first attenuation and polarization rotation will be performed The second signal light is attenuated to obtain the second signal light without phase modulation, and the first signal light with polarization rotation and second phase modulation and the second signal light without phase modulation are sent to the first port; Sending the first signal light without phase modulation and the second signal light without phase modulation to the second port includes: attenuating the second signal light for the first time to obtain the second signal light after the first attenuation; Rotate the polarization of the second signal light after the first attenuation by 90 degrees to obtain the second signal light that undergoes the first attenuation and polarization rotation; attenuate the second signal light that undergoes the first attenuation and polarization rotation to obtain The second signal light without phase modulation, the first signal light without phase modulation and the second signal light without phase modulation are sent to the second port.

Optionally, the signal light is a quantum optical signal, the first signal light is a first quantum optical signal, and the second signal light is a second quantum optical signal; the first port is connected to a quantum optical signal receiver; the indication information is obtained, and according to the indication information Generating pulsed pump light includes: receiving a synchronous optical signal; determining indication information according to the synchronous optical signal; wherein, the indication information indicates pulse time information of the quantum optical signal; generating pulsed pump light according to the indication information; wherein, the pulsed pump light The pulse time information of the is matched with the pulse time information of the quantum optical signal.

In the embodiment of the present invention, the signal light is divided into the first signal light and the second signal light; pulse pump light is generated according to the instruction information; in the case of pulse pump light, the pulse pump light is used to control the first signal light The phase of the first phase modulation is performed, and the polarization of the first signal light after the first phase modulation is rotated by 90 degrees to obtain the first signal light with the first phase modulation and polarization rotation, and the pulsed pump light is used to The phase of the first signal light that undergoes the first phase modulation and the polarization rotation is subjected to the second phase modulation to obtain the first signal light that is the polarization rotation and the second phase modulation is performed, and the polarization is rotated and the second phase modulation is performed The first signal light without phase modulation and the second signal light without phase modulation are sent to the first port; in the absence of pulsed pump light, the first signal light without phase modulation and the second signal without phase modulation Light is sent to the second port. After the first phase modulation of the first signal light is performed by the pulse pump light, the polarization of the first signal light after the first phase modulation is rotated by 90 degrees, and then the second phase is performed by the pulse pump light. Modulation, so that the phase modulation of the first signal light is independent of the polarization of the pulsed pump light, so that the phase difference between the first signal light and the second signal light can be obtained more accurately.

Those skilled in the art should understand that the embodiments of the present invention may be provided as methods or computer program products. Accordingly, the present invention can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It should be understood that each procedure and/or block in the flowchart and/or block diagram, and a combination of procedures and/or blocks in the flowchart and/or block diagram can be realized by computer program instructions. These computer program instructions may be provided to a general purpose computer, special purpose computer, embedded processor, or processor of other programmable data processing equipment to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing equipment produce a An apparatus for realizing the functions specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to operate in a specific manner, such that the instructions stored in the computer-readable memory produce an article of manufacture comprising instruction means, the instructions The device realizes the function specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions can also be loaded onto a computer or other programmable data processing device, causing a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process, thereby The instructions provide steps for implementing the functions specified in the flow chart or blocks of the flowchart and/or the block or blocks of the block diagrams.

Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims (14)

1. A time-domain filtering device, characterized in that it comprises a coupling unit, a processing unit connected to the coupling unit; a pulsed pump light generating unit connected to the processing unit; the coupling unit includes a first port and Second port; where: The coupling unit is configured to receive signal light, divide the signal light into first signal light and second signal light, and send the first signal light to the processing unit; In the case of transmitting the polarization-rotated and second-phase-modulated first signal light, transmitting the polarization-rotated and second-phase-modulated first signal light and the second signal light without phase modulation to the first port of the coupling unit; in the case of receiving the first signal light without phase modulation sent by the processing unit, the first signal light without phase modulation and the sending the phase-modulated second signal light to the second port of the coupling unit; The pulsed pumping light generation unit is configured to acquire indication information, generate pulsed pumping light according to the indication information; and send the generated pulsed pumping light to the processing unit; The processing unit is configured to, in the case of receiving the pulsed pumping light sent by the pulsed pumping light generating unit, perform a first phase modulation on the phase of the first signal light by the pulsed pumping light , the polarization of the first signal light undergoing the first phase modulation is rotated by 90 degrees to obtain the first signal light undergoing the first phase modulation and polarization rotation, and the first phase performing a second phase modulation on the phase of the modulated and polarization-rotated first signal light, obtaining the first signal light with the polarization rotation and second phase modulation, and performing the polarization rotation and second phase modulation Send the first signal light to the coupling unit; if the pulse pump light sent by the pulse pump light generation unit is not received, send the first signal light without phase modulation to the the coupling unit. 2. The time-domain filtering device according to claim 1, wherein the coupling unit further comprises a third port and a fourth port; the coupling unit is configured to: receiving signal light through the second port, and dividing the signal light into first signal light and second signal light; sending the first signal light to the processing unit through the third port; sending the second signal light through the fourth port; receiving the polarization-rotated first signal light with a second phase modulation or the first signal light without phase modulation through the third port; receiving the second signal light without phase modulation through the fourth port; In the case of receiving the first signal light sent by the processing unit through the third port, the polarization rotation and the second phase modulation are performed, the polarization rotation received through the third port and the second phase modulation are performed. sending the second phase-modulated first signal light and the second signal light received through the fourth port without phase modulation to the first port of the coupling unit; When the first signal light without phase modulation sent by the processing unit is received through the third port, the first signal light without phase modulation received through the third port and The second signal light without phase modulation received through the fourth port is sent to the second port of the coupling unit. 3. The time-domain filtering device according to claim 1 or 2, wherein the processing unit comprises: a multiplexing/demultiplexing unit connected to the pulsed pump light generating unit and the coupling unit, a medium unit connected to the multiplexing/demultiplexing unit, and a first Faraday rotating mirror unit connected to the medium unit; The multiplexing/demultiplexing unit is configured to, in the case of receiving the pulsed pumping light sent by the pulsed pumping light generating unit, combine the pulsed pumping light with the received coupling unit Coupling the first signal light sent to obtain the first coupled signal light; sending the first coupled signal light to the medium unit; demultiplexing the fourth coupled signal light to obtain the polarization rotation and performing the second phase-modulated first signal light, and sending the polarization-rotated and second-time phase-modulated first signal light to the coupling unit; The dielectric unit is configured to make the pulsed pump light in the first coupled signal light perform a first phase modulation on the phase of the first signal light in the first coupled signal light in the dielectric unit , to obtain the first signal light for the first phase modulation and the second coupled signal light coupled with the pulsed pump light, and send the second coupled signal light to the first Faraday rotator mirror unit; make the The pulsed pump light in the third coupled signal light performs a second phase modulation on the phase of the first signal light with polarization rotation in the third coupled signal light in the medium unit. secondary phase modulation to obtain the second phase modulated and polarization-rotated first signal light and the fourth coupled signal light coupled with the pulsed pumping light, and send the fourth coupled signal light to the complex Use/demultiplex unit; The first Faraday rotator mirror unit is used to rotate the polarization of the first signal light after the first phase modulation in the second coupling signal light by 90 degrees, to obtain the first phase modulation and polarization rotation The third coupled signal light coupled with the first signal light of the pulsed pump light; sending the third coupled signal light to the dielectric unit. 4. The time-domain filtering device according to claim 3, wherein the multiplexing/demultiplexing unit is also used for: When the pulsed pumping light sent by the pulsed pumping light generating unit is not received, the received first signal light sent by the coupling unit is sent to the first signal light through the dielectric unit. a Faraday rotating mirror unit; The first Faraday rotating mirror unit is used for: rotating the polarization of the received first signal light by 90 degrees to obtain the first signal light without phase modulation; passing the first signal light without phase modulation through the medium in sequence unit and the multiplexing/demultiplexing unit are sent to the coupling unit. 5. The time domain filtering device according to any one of claims 1 to 4, wherein the time domain filtering device further comprises a second Faraday rotating mirror unit connected to the coupling unit; The second Faraday rotating mirror unit is used for: receiving the second signal light sent by the coupling unit, rotating the polarization of the second signal light by 90 degrees to obtain the second signal light without phase modulation, and converting the second signal light without phase modulation sending signal light to the coupling unit; The coupling unit is used for: In the case of receiving the first signal light with polarization rotation and second phase modulation sent by the processing unit, combine the first signal light with polarization rotation and second phase modulation with the first signal light without phase modulation The modulated second signal light is sent to the first port of the coupling unit; when the first signal light without phase modulation sent by the processing unit is received, the second signal light without phase modulation is received The first signal light and the second signal light without phase modulation are sent to the second port of the coupling unit. 6. The time-domain filter device according to any one of claims 1 to 4, wherein the time-domain filter device further comprises: an attenuation unit connected to the coupling unit, and an attenuation unit connected to the attenuation unit Second Faraday rotating mirror unit; The attenuation unit is used for: receiving the second signal light sent by the coupling unit, attenuating the second signal light for the first time to obtain the second signal light after the first attenuation, and sending the second signal light after the first attenuation to The second Faraday rotator mirror unit; receiving the first attenuation and polarization-rotated second signal light sent by the second Faraday rotator mirror unit, and converting the first attenuation and polarization-rotated second signal light performing a second attenuation to obtain the second signal light without phase modulation, and sending the second signal light without phase modulation to the coupling unit; The second Faraday rotating mirror unit is used for: receiving the first attenuated second signal light sent by the attenuating unit, and rotating the polarization of the first attenuated second signal light by 90 degrees to obtain the first attenuated and polarized second signal light signal light, and sending the first attenuated and polarized second signal light to the attenuation unit; The coupling unit is used for: In the case of receiving the polarization-rotated and second-phase-modulated first signal light sent by the processing unit, the polarization-rotated and second-phase-modulated first signal light and the The second signal light with phase modulation is sent to the first port of the coupling unit; when the first signal light without phase modulation sent by the processing unit is received, all the light without phase modulation The first signal light and the second signal light without phase modulation are sent to the second port of the coupling unit. 7. The time-domain filtering device according to any one of claims 1 to 6, wherein the signal light is a quantum optical signal, the first signal light is a first quantum optical signal, and the second The signal light is the second quantum optical signal; the first port is connected to the quantum optical signal receiver; The pulsed pump light generating unit is used for: Receive synchronous optical signal; determining the indication information according to the synchronous optical signal; wherein, the indication information indicates pulse time information of the quantum optical signal; The pulsed pump light is generated according to the indication information; wherein, the pulse time information of the pulsed pump light matches the pulse time information of the quantum optical signal. 8. A time-domain filtering method, characterized in that, comprising: receiving signal light, and dividing the signal light into first signal light and second signal light; Acquire instruction information, and generate pulsed pump light according to the instruction information; In the case of the pulsed pumping light, the first phase modulation is performed on the phase of the first signal light by the pulsed pumping light, and the polarization of the first signal light after the first phase modulation is rotated by 90 degrees, to obtain the first signal light that undergoes the first phase modulation and polarization rotation, and the phase of the first signal light that undergoes the first phase modulation and polarization rotation is performed for the second time by the pulsed pumping light Phase modulation, obtaining the first signal light with polarization rotation and second phase modulation, and combining the first signal light with polarization rotation and second phase modulation and the second signal without phase modulation sending light to the first port; In the absence of the pulsed pump light, the first signal light without phase modulation and the second signal light without phase modulation are sent to a second port. 9. The time-domain filtering method according to claim 8, wherein the receiving signal light and dividing the signal light into a first signal light and a second signal light comprise: receiving signal light through the second port; splitting the signal light into the first signal light and the second signal light; sending the first signal light through a third port, and sending the second signal light through the fourth port; The sending the first signal light with the polarization rotation and the second phase modulation and the second signal light without phase modulation to the first port includes: sending the polarization-rotated first signal light received through the third port with the second phase modulation and the second signal light received through the fourth port without phase modulation to the coupling said first port of the unit; The sending the first signal light without phase modulation and the second signal light without phase modulation to the second port includes: sending the first signal light without phase modulation received through the third port and the second signal light without phase modulation received through the fourth port to the second port of the coupling unit . 10. The time-domain filtering method according to claim 8 or 9, characterized in that, in the presence of the pulsed pumping light, the phase of the first signal light is carried out for the first time by the pulsed pumping light One phase modulation, the polarization of the first signal light after the first phase modulation is rotated by 90 degrees to obtain the first signal light with the first phase modulation and polarization rotation, and the pulsed pump light is used to The phase of the first signal light that undergoes the first phase modulation and the polarization rotation is subjected to the second phase modulation, and the first signal light that undergoes the polarization rotation and the second phase modulation is obtained, including: In the presence of the pulsed pump light, coupling the pulsed pump light with the first signal light to obtain a first coupled signal light; sending the first coupled signal light to a dielectric unit, through the phase of the first signal light in the first coupled signal light in the dielectric unit by the pulsed pump light in the first coupled signal light performing the first phase modulation to obtain the first signal light subjected to the first phase modulation and the second coupled signal light coupled with the pulsed pump light; Rotating the polarization of the first signal light after the first phase modulation in the second coupled signal light by 90 degrees to obtain the first signal light with the first phase modulation and polarization rotation and the pulse pumping Optically coupled third coupled signal light; sending the third coupled signal light to the dielectric unit, and performing the first pumping of the third coupled signal light in the dielectric unit by the pulsed pump light in the third coupled signal light The second phase modulation is performed on the phase of the phase-modulated and polarized-rotated first signal light to obtain the second phase-modulated and polarized-rotated first signal light and the fourth coupled signal light coupled with the pulsed pumping light ; Demultiplexing the fourth coupled signal light to obtain the first signal light whose polarization is rotated and phase modulated for the second time. 11. The time-domain filtering method according to any one of claims 8 to 10, characterized in that, in the absence of the pulsed pump light, there will be no phase-modulated first signal light and before sending the second signal light without phase modulation to the second port, further comprising: In the absence of the pulsed pump light, the polarization of the first signal light is rotated by 90 degrees to obtain the first signal light without phase modulation. 12. The time-domain filtering method according to any one of claims 8 to 11, wherein the first signal light that rotates the polarization and undergoes a second phase modulation and the first signal light that does not undergo phase modulation The second signal light is sent to the first port, including: Rotating the polarization of the second signal light by 90 degrees to obtain the second signal light without phase modulation; sending the modulated second signal light to the first port; The sending the first signal light without phase modulation and the second signal light without phase modulation to the second port includes: Rotating the polarization of the second signal light by 90 degrees to obtain the second signal light without phase modulation; combining the first signal light without phase modulation with the second signal without phase modulation Light is sent to the second port. 13. The time-domain filtering method according to any one of claims 8 to 11, wherein the first signal light that rotates the polarization and undergoes a second phase modulation and the first signal light that does not undergo phase modulation The second signal light is sent to the first port, including: Attenuating the second signal light for the first time to obtain the second signal light after the first attenuation; rotating the polarization of the second signal light after the first attenuation by 90 degrees to obtain the first attenuation and Polarization-rotated second signal light; attenuating the first attenuation and polarization-rotated second signal light to obtain the second signal light without phase modulation, rotating the polarization and performing a second sending the phase-modulated first signal light and the second signal light without phase modulation to the first port; The sending the first signal light without phase modulation and the second signal light without phase modulation to the second port includes: Attenuating the second signal light for the first time to obtain the second signal light after the first attenuation; rotating the polarization of the second signal light after the first attenuation by 90 degrees to obtain the first attenuation and Polarization-rotated second signal light; attenuating the second signal light that undergoes first attenuation and polarization rotation to obtain the second signal light that is not phase-modulated, and the first signal light that is not phase-modulated The signal light and the second signal light without phase modulation are sent to the second port. 14. The time-domain filtering method according to any one of claims 8 to 13, wherein the signal light is a quantum optical signal, the first signal light is a first quantum optical signal, and the second The signal light is the second quantum optical signal; the first port is connected to the quantum optical signal receiver; The acquiring instruction information, generating pulsed pump light according to the instruction information includes: Receive synchronous optical signal; determining the indication information according to the synchronous optical signal; wherein, the indication information indicates pulse time information of the quantum optical signal; The pulsed pump light is generated according to the indication information; wherein, the pulse time information of the pulsed pump light matches the pulse time information of the quantum optical signal.