JPH0915661A - Full light type time-division light pulse multiplex separating circuit and full light type tdm-wdm conversion circuit and full light type time-division channel drop circuit - Google Patents

Abstract

PURPOSE: To embody a full light type time-division multiplex separating circuit which integrally outputs the respective low order group signal channel of time-division multiplex signal light to respectivley different output ports. CONSTITUTION: This separating circuit has an optical amplifier means 8 which amplifiers and outputs the time-division multiplex signal light of a wavelength λs formed by time-division multiplexing of N pieces of the low order group signal channels, a station light emitting source 10 which generates station light emitted pulse trains having wavelengths λ1, λ2,...λN varying from each other in synchronization with the respective low order group signal channels, an optical coupling means 9 of 2×2 which inputs the station light emitted pulse trains to the first input port 9A and branches these pulse trains one to one to two output ports 9C, 9D, an optical Kerr medium 4 which couples the two output ports 9C, 9D of the optical coupling means 9 to each other, an optical multiplexing means 6 which multiplexes the time-division multiple signal light amplified by the station light emitted light pulse trains branched to the one output port 9C of the optical coupling means 9 and inputs the signal light to the optical Kerr medium 4 and an optical demultiplexing means 7 which demultiplexes the station emitted light of the wavelength corresponding to the respective low order group signal channels of the time-division multiple signal light and outputs the demultiplexed light to the ports corresponding to the respective wavelengths.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-channel for dividing time-division multiplexed signal light on the time axis by utilizing the optical Kerr effect and collectively outputting each low-order group signal channel to different output ports. The present invention relates to an output-type all-optical time-division optical pulse demultiplexing circuit. Further, the present invention is an all-optical TDM-WDM that assigns different wavelengths to the respective low-order group signal channels of the time division multiplexed signal light input from the transmission line, converts it into wavelength division multiplexed signal light, and sends it out to the transmission line. Regarding the conversion circuit.

The present invention also relates to an all-optical time division channel drop circuit for separating time division multiplexed signal light on the time axis by utilizing the optical Kerr effect and extracting an arbitrary low order group signal channel.

[0003]

2. Description of the Related Art FIG. 17 shows a configuration example of a conventional all-optical time division optical pulse demultiplexing circuit using the optical Kerr effect. In the figure, the time-division multiplexed signal light (wavelength λs) is input to the optical multiplexer 2 via the optical circulator 5, and is multiplexed with the control light (wavelength λc) having a wavelength different from that of the signal light to generate a wavelength dependence of 2 × 2. To the input port 1A of the optical coupler 1. Here, the control light is a local oscillation pulse train having a repetition equal to one of the low-order group signal channels forming the time-division multiplexed signal light, and is multiplexed in time synchronization with the low-order group signal channel. It The branching ratio of the wavelength-dependent optical coupler 1 depends on the wavelength. The time-division multiplexed signal light is branched to the output ports 1C and 1D on a one-to-one basis, and the control light is output to one output port (here, 1).
100% is led to C). The output ports 1C and 1D of the wavelength-dependent optical coupler 1 are coupled to both ends of the optical Kerr medium 4 to form a loop. The light output from the input port 1B of the wavelength-dependent optical coupler 1 is input to the optical demultiplexer 3 and the control light and the signal light are demultiplexed.

Here, the time-division multiplexed signal lights equally split into the output ports 1C and 1D of the wavelength-dependent optical coupler 1 propagate in the optical Kerr medium 4 in opposite directions and output ports 1C and 1D.
To the output port 1C, and the control light branched to the output port 1C propagates through the optical Kerr medium 4 in one direction (here, clockwise) and is input to the output port 1D. At this time, the clockwise signal light that advances in the same direction as the control light in terms of time causes a phase change ΔΦ due to the mutual phase modulation in the optical Kerr medium 4. The phase change ΔΦ is ΔΦ = 2n ₂ k _S IL, where n _{2 is} the nonlinear constant of the optical Kerr medium 4, L is the length of the optical Kerr medium 4, I is the intensity of the control light, and k _S is the wave number of the signal light. … (1).

On the other hand, the signal light traveling counterclockwise (counterclockwise) with respect to the control light undergoes an average phase change due to the control light, and the phase change has a small value proportional to the average power of the control light. Therefore, the phase difference between the signal lights that have passed through the loop clockwise and counterclockwise and combined again by the wavelength dependent optical coupler 1 can be set to π and 0 depending on the presence or absence of the control light. When the phase difference is π, the signal light is guided to the input port 1B different from that at the time of incidence, and when the phase difference is 0, it returns to the input port 1A at the time of incidence. That is, of the signal light pulse train, only the pulse that temporally overlaps the control light pulse in the optical Kerr medium 4 is input to the optical demultiplexer 3 from the input port 1B, and the separated signal is output from the output port of the optical demultiplexer 3. It is output as light 1. The remaining signal light is input from the input port 1A to the optical circulator 5 via the optical multiplexer 2, and is output as the separated signal light 2 from the output port of the optical circulator 5.

As described above, the control light having a bit rate equal to that of one low-order group signal channel of the time-division multiplexed signal light is multiplexed in time synchronization with the low-order group signal channel to thereby reduce the low-order group signal channel. The next group signal channel can be taken out from the optical demultiplexer 3 as the separated signal light 1, and can function as an all-optical time-division optical pulse demultiplexing circuit.

[0007]

The conventional all-optical time division optical pulse demultiplexing circuit can only separate a specific channel synchronized with the control light from the time division multiplexed signal light and other channels. Therefore, in order to completely separate the N multiplexed channels, it is necessary to configure N-1 optical pulse demultiplexing circuits in multiple stages.

However, when a plurality of optical pulse demultiplexing circuits are configured in multiple stages, there are various problems such as mutual synchronization of each stage, increase of insertion loss, increase of delay time and the like. Therefore, conventionally, there has been a demand for a configuration capable of simultaneously separating and outputting a large number of channels with one optical pulse demultiplexing circuit.
The present invention provides a multi-channel output type all-optical time-division optical pulse demultiplexing circuit that collectively outputs each low-order group signal channel of time-division multiplexed signal light to a different output port. An object of the present invention is to provide an all-optical TDM-WDM conversion circuit for converting to wavelength division multiplexed signal light and an all-optical time-division channel drop circuit for extracting an arbitrary low-order group signal channel of time-division multiplexed signal light. .

[0009]

The all-optical type time division optical pulse demultiplexing circuit of the present invention inputs time division multiplexed signal light of wavelength λs obtained by time division multiplexing N low order group signal channels, and outputs a predetermined signal. Optical amplification means for amplifying and outputting the intensity of the local light and local light for generating local light pulse trains having different wavelengths λ1, λ2, ..., λN in synchronization with each low-order group signal channel of the time division multiplexed signal light. Source and local oscillation pulse train are input to the first input port, and 2 × 2 optical coupling means for branching to two output ports in a one-to-one relationship, and an optical car coupling between two output ports of the optical coupling means An optical multiplexing means for multiplexing the time-division multiplexed signal light output from the optical amplifying means with the medium and the local oscillation pulse train branched to one output port of the optical coupling means, and inputting to the optical Kerr medium; From the light that has propagated through the medium, Wavelength .lambda.1, .lambda.2 corresponding to le,
, .Lambda.N for demultiplexing the local oscillation light and outputting it to a port corresponding to each wavelength.

The all-optical time-division optical pulse demultiplexing circuit of the present invention performs chirping in which the optical frequency changes linearly with time in synchronization with each low-order group signal channel of the time-division multiplexed signal light. A local light source is used that produces local light having a time width that includes and has N low order signal channels. The all-optical TDM-WDM conversion circuit of the present invention removes the time-division multiplexed signal light from the light propagated through the optical Kerr medium, instead of the optical demultiplexing means of the all-optical time-division optical pulse demultiplexing circuit, Wavelength λ1,
Optical demultiplexing means for outputting local light of λ2, ..., λN as wavelength division multiplexed signal light instead of time division multiplexed signal light is provided.

The all-optical time-division channel drop circuit of the present invention replaces the local light source and the optical demultiplexing means of the all-optical time-division optical pulse demultiplexing circuit with M pieces of the time-division multiplexed signal light to be separated. Local light source that generates local light pulse trains each having a predetermined wavelength in synchronism with the low-order group signal channel, and time-division multiplexed signal light and M from the light propagated through the optical Kerr medium.
Optical demultiplexing means for demultiplexing the local oscillation light corresponding to the individual low-order group signal channels.

In the polarization-independent all-optical time-division optical pulse demultiplexing circuit, all-optical TDM-WDM conversion circuit, and all-optical time-division channel drop circuit, the optical Kerr medium has birefringence. In addition, the local light source includes a birefringence compensating means for compensating the polarization dispersion between the two principal axes, and the local light source has two polarization components in the directions of two orthogonal principal axes of the optical Kerr medium having the same intensity. A local light pulse train having the following polarization is generated.

[0013]

In the structure of the present invention, the time division multiplexed signal light propagates in one direction and the local light propagates in both directions through the optical Kerr medium connecting the two output ports of the optical coupler. That is, the time division multiplexed signal light in the conventional configuration corresponds to the local light, and the control light corresponds to the time division multiplexed signal light. Therefore, a phase shift due to the optical Kerr effect (mutual phase modulation) is induced on the local oscillation light, and the local oscillation light is intensity-modulated by each low-order group signal channel of the time division multiplexed signal light and output from the optical coupler. . That is, each low-order group signal channel of the time-division multiplexed signal light is converted into the wavelengths λ1, λ2, ..., λN of local light and output.

2 and 3 show the relationship between time division multiplexed signal light and local light in the all-optical time division optical pulse demultiplexing circuit of the present invention. As shown in FIG. 2, the low-order group signal channels of channels 1, 2, ..., N of the time division multiplexed signal light and the local oscillation pulse trains of wavelengths λ1, λ2, ..., λN are made to overlap in time. By multiplexing, local oscillation light intensity-modulated by each low-order group signal channel of time division multiplexed signal light is output. By demultiplexing the local oscillation light of the wavelengths λ1, λ2, ..., λN to the port corresponding to each wavelength, each low-order group signal channel is separated at once.

Further, as shown in FIG. 3, even if local oscillation light having linear chirping and having a time width including N low order group signal channels is used, each low order of the time division multiplexed signal light is used. The local light whose intensity is modulated by the group signal channel is cut out, and similarly, each low-order group signal channel can be separated at once. FIG. 12 shows an all-optical TDM-WDM of the present invention.
The relation between time division multiplexed signal light and local light in the conversion circuit is shown. Here, channels 1, 2 of the time division multiplexed signal light,
, N low order group signal channels and wavelengths λ1, λ2, ..., λ
By multiplexing the N 2 local light pulse trains so as to overlap with each other in time, the local light whose intensity is modulated by each low-order group signal channel of the time division multiplexed signal light is output. The local oscillation light of the wavelengths λ1, λ2, ..., λN becomes the wavelength division multiplexed signal light.

FIG. 14 shows the relationship between time division multiplexed signal light and local light in the all-optical time division channel drop circuit of the present invention. Here, the low-order group signal channels of channels 1, 2 and 4 extracted from the time division multiplexed signal light and the wavelengths λ1 and λ
By multiplexing the local oscillation pulse trains of 2, λ4 so as to overlap in time, the local oscillation light intensity-modulated by each low-order group signal channel of the time division multiplexed signal light is output. The local light of wavelengths λ1, λ2, and λ4 becomes drop channel signal light. Each drop channel signal light can be separated into each channel by an optical demultiplexer.

[0017]

【Example】

(First Embodiment of All-Optical Time Division Optical Pulse Multiplexing / Demultiplexing Circuit) FIG. 1 shows the configuration of the first embodiment of the all-optical time division optical pulse multiplexing / demultiplexing circuit of the present invention. In the figure, the local light source 10 is connected to the input port 9A of the optical coupler 9, and the output port 9A
C and 9D are coupled via the optical multiplexer 6 and the optical Kerr medium 4, and the optical demultiplexer 7 with 1 input and N output is connected to the input port 9B.

The time-division multiplexed signal light of wavelength λs obtained by time-division-multiplexing the low-order group signal channels of channel 1 to channel N is input to the optical multiplexer 6 via the optical amplifier 8. The local light source 10 generates local light having different wavelengths λ1, λ2, ..., λN in synchronization with each low-order group signal channel of the time division multiplexed signal light. This local oscillation light is input to the input port 9A of the optical coupler 9 and is output to the output port 9 with a branching ratio of 1: 1.
Output to C and 9D. On the other hand, the time division multiplexed signal light amplified by the optical amplifier 8 is multiplexed by the optical multiplexer 6 with the local oscillation light output from the output port 9C of the optical coupler 9. At this time, each low-order group signal channel of the time division multiplexed signal light and the local oscillation pulse trains of wavelengths λ1, λ2, ..., λN are multiplexed so as to overlap in time.

Between the local oscillator light propagating in the clockwise direction and the local oscillator light propagating in the counterclockwise direction in the optical Kerr medium 4, there is a phase difference depending on the presence or absence of the data of each low-order group signal channel of the time division multiplexed signal light. Is induced and is divided into local light output to the input port 9B or 9A of the optical coupler 9. That is, the local light whose intensity is modulated by each low-order group signal channel of the time division multiplexed signal light is output from the input port 9B of the optical coupler 9.
The local light output from the input port 9B of the optical coupler 9 is
The optical demultiplexer 7 separates and outputs to the output port according to each wavelength. The optical multiplexer 6 that multiplexes the time division multiplexed signal light
Is the same when connected to the output port 9D of the optical coupler 9.

FIG. 4 shows a configuration example of the optical demultiplexer 7 having one input and N outputs. The optical demultiplexer shown in (a) is composed of an optical branching device 21 for branching the input light into N and optical filters 22-1 to 22-N having transmission wavelengths of λ1, λ2, ..., λN. The optical demultiplexer shown in (b) is composed of a reflection type diffraction grating 23.
The optical demultiplexer shown in (c) is composed of an arrayed waveguide diffraction grating 24. The arrayed waveguide diffraction grating 24 includes an input waveguide 25, a slab waveguide 26, an arrayed waveguide (adjacent waveguides have an optical path length difference of ΔL) 27, a slab waveguide 28, and an output waveguide array 29. Composed. The light distributed from the input waveguide 25 to the arrayed waveguide 27 via the slab waveguide 26 has a different phase state after passing through the arrayed waveguide 27 due to the difference in optical frequency, and the convergence position in the slab waveguide 28 is It depends on the optical frequency. Therefore, lights of different optical frequencies are taken out to the respective waveguides of the output waveguide array 29, and function as an optical demultiplexer.

FIG. 5 shows the configuration of the first embodiment of the local oscillator light source 10. The local light source 10 shown in (a) has wavelengths λ1, λ2, ...,
It is composed of light sources 31-1 to 31-N for outputting local light of λ N, optical delay devices 32-1 to 32-N corresponding to the respective light sources, and an optical multiplexer 33 having N inputs and one output. The local light of each wavelength is given an appropriate delay by the optical delay devices 32-1 to 32-N so as to be overlapped with each low-order group signal channel of the time division multiplexed signal light on the time axis, and the optical multiplexer 33. Combined and output. Note that the correspondence relationship between each low-order group signal channel and the wavelength of local oscillation light is arbitrary.

(B) and (c) show light sources which replace the light sources 31-1 to 31-N. The light source shown in (b) is a broadband light source 34 that outputs white pulsed light having a sufficiently wide spectrum including wavelengths λ1 to λN, and wavelengths λ1, λ from the white pulsed light.
2, ..., .lamda.N local light is demultiplexed and output by a 1-input N-output optical demultiplexer 35. The optical demultiplexer 35 is shown in FIG.
The configuration shown in can be used.

The light source shown in (c) is a multi-wavelength light source 36 that simultaneously outputs optical pulses of wavelengths λ1 to λN, and local light of wavelengths λ1, λ2, ..., λN is demultiplexed from this multi-wavelength pulsed light. It is composed of an optical demultiplexer 35 with 1 input and N outputs.
The optical demultiplexer 35 is compatible with the configuration shown in FIG. FIG.
Shows the configuration of the second embodiment of the local light source 10.

The local light source 10 of this embodiment is a multi-wavelength light source 3
6 and the wavelength dispersion medium 37 are connected. The multi-wavelength pulsed light of wavelengths λ1 to λN output from the multi-wavelength light source 36 is delayed according to each wavelength so that the low-order group signal channels of the time division multiplexed signal light are overlapped on the time axis by the wavelength dispersion medium 37. Is output and is output as a local oscillation pulse train. Therefore, in the present embodiment, each low-order group signal channel and the wavelength of local oscillation light have a predetermined relationship.

FIG. 7 shows the configuration of a third embodiment of the local oscillator light source 10. The local light source 10 of this embodiment is configured by connecting a broadband light source 34, a periodic filter 38, and a wavelength dispersion medium 37. The broadband light source 34 outputs white pulsed light having a sufficiently wide spectrum including wavelengths λ1 to λN. The periodic filter 38 converts wavelengths λ1, λ2, ..., From the white pulsed light.
The local light of λN is cut out and output. The local oscillation light is delayed by the wavelength dispersion medium 37 so as to overlap each low-order group signal channel of the time division multiplexed signal light on the time axis, and is output as a local oscillation pulse train. Therefore, in the present embodiment, each low-order group signal channel and the wavelength of local oscillation light have a predetermined relationship.

In this embodiment, the time-division multiplexed signal light that is bit-multiplexed is assumed. However, by adapting the wavelength configuration of the local oscillation pulse train to the multiplexing form of the time-division multiplexed signal light, not only bit multiplexing but also byte multiplexing or It is also possible to separate the signal light in packet units. Further, as in this embodiment, by setting the wavelengths λ1, λ2, ..., λN of the local oscillation light to be different from each other, it is possible to collectively separate the respective low-order group signal channels of the time division multiplexed signal light. By setting the same wavelength for a predetermined channel, for example, a bit rate down converter or the like can be configured.

FIG. 8 shows the configuration of a first embodiment of a local oscillator light source that generates local oscillator light having linear chirping. The local light source of this embodiment is configured by connecting a white pulse generating optical fiber 51, a chirp adjusting optical fiber 52, and a wavelength tunable bandpass optical filter 53. When a short light pulse (optical frequency ν ₀ ) is incident on the white pulse generating optical fiber 51, a broadband white pulse (center optical frequency ν ₀ ) is generated. For example, when a short optical pulse of several picoseconds having a peak power of 2 to 3 W is incident on the white pulse generating optical fiber 51 having a length of 1 km, a white pulse having a spectral width of about 200 nm or more is generated.

The wavelength tunable bandpass optical filter 53 has a rectangular spectral transmission function, and when a white pulse input through the chirp adjusting optical fiber 52 is filtered, local oscillation light having a wide time width and linear chirping is generated. Is output. Further, by changing the central transmission wavelength within the white pulse wavelength range, it is possible to generate local oscillation light having linear chirping at an arbitrary optical frequency. The chirp adjusting optical fiber 52 adjusts the absolute value and sign of chirping according to its dispersion characteristics.

FIG. 9 shows the configuration of a second embodiment of a local oscillator light source that generates local oscillator light having linear chirping. The local light source of this embodiment uses an ordinary dispersion optical fiber 54 having ordinary dispersion (positive dispersion). When a short optical pulse (optical frequency ν ₀ ) is incident on the ordinary dispersion optical fiber 54, a control optical pulse having a wide time width and linear chirping is generated due to the self-phase modulation effect and the combined effect of dispersion. this is,
This is the same principle as the pulse compression method for optical pulses.

However, in order to obtain a spectral width of 200 nm using the 1 km ordinary dispersion optical fiber 54, a short optical pulse having a peak power of about 200 to 300 W and a pulse width of about 3 ps is required, and a white pulse is used. It requires about 100 times more pump power than the case. It should be noted that the inclination of chirping is usually a blue shift, and when redshift chirping is required, dispersion is controlled by using an optical fiber having anomalous dispersion (negative dispersion). Also in this generation method, a control light pulse having linear chirping can be generated at an arbitrary optical frequency by changing the center transmission wavelength of the wavelength tunable bandpass optical filter within the generated wavelength range.

(Second Embodiment of All-Optical Time Division Optical Pulse Multiplexing / Demultiplexing Circuit) FIG. 10 shows the configuration of the second embodiment of the all-optical type time division optical pulse multiplexing / demultiplexing circuit of the present invention. The present embodiment has a configuration that enables demultiplexing that does not depend on the polarization state of the input time division multiplexed signal light. The basic configuration is the same as that of the all-optical time division optical pulse demultiplexing circuit of the first embodiment. In this embodiment, the output ports 9C and 9D of the optical coupler 9 are connected in a loop through the birefringent optical Kerr medium 4'and the birefringence compensating means 11, and the local oscillation light is linearly polarized and its polarization plane is changed. The input is made so as to form 45 degrees with the principal axis of the birefringent optical Kerr medium 4 '.

As the birefringent optical Kerr medium 4 ', for example, a birefringent polarization maintaining optical fiber is used. The birefringence compensating means 11 is arranged so that the two principal axes of the birefringence are switched at the midpoint of the birefringent optical Kerr medium 4 ′, and is configured to compensate the polarization dispersion due to the birefringence as a whole. As the birefringence compensating means 11, for example, a method in which birefringent polarization-maintaining optical fibers are twisted by 90 ° and fusion-spliced, λ / 2
There is a method using a plate or a Faraday rotator.

In the configuration of this embodiment, the time-division multiplexed signal light and the local light are separately propagated in the two linearly polarized waves of the birefringent optical Kerr medium 4'in the directions of the orthogonal main axes. At this time, the transmittance T of the local oscillator light is expressed by the following: if the angle formed by the polarization direction of the time division multiplexed signal light and the principal axis of the optical Kerr medium is θ, and the phase shift amount that the time division multiplexed signal light gives to the local light is Δφ,

[0034]

(Equation 1)

It is expressed as follows. According to the equation (2), the transmittance T of the local light becomes constant (= 0.5) when Δφ = π, and the demultiplexing operation that does not depend on the polarization state of the time division multiplexed signal light becomes possible. When the signal light pulse waveform is Gaussian, the signal light power I _{S for} Δφ = π is

[0036]

(Equation 2)

## EQU3 ## Here, _kl is the wave number of the local oscillation light, τ is the walk-off of the time division multiplexed signal light and the entire length of the optical Kerr medium of the local oscillation light, and T ₀ is the full width at half maximum of the time division multiplexed signal. The optical amplifier 8 receives the power of the time division multiplexed signal light as I
Amplify to become _S. This enables demultiplexing that does not depend on the polarization state of the input time division multiplexed signal light.

(Embodiment of All-Optical TDM-WDM Conversion Circuit) FIG. 11 shows the configuration of an embodiment of the all-optical TDM-WDM conversion circuit of the present invention. The feature of this embodiment is that, in the configuration of the first embodiment of the all-optical type time division optical pulse demultiplexing circuit shown in FIG. 1, a wavelength λ is used instead of the 1-input N-output optical demultiplexer 10.
The optical filter 12 eliminates the time-division multiplexed signal light of s and passes the local light of wavelengths λ1 to λN.

In this embodiment, the local light of wavelengths λ1, λ2, ..., λN is
The low-order group signal channels of the time-division multiplexed signal light undergo intensity modulation, and are output from the input port 9B of the optical coupler 9 together with the time-division multiplexed signal light and input to the optical filter 12. In the local oscillation light output from the optical filter 12, each low-order group signal channel of the time division multiplexed signal light has wavelengths λ1, λ2, ..., λ.
It is output as wavelength division multiplexed signal light replaced with N.

The optical multiplexer 6 for multiplexing the time-division multiplexed signal light is the same even if it is connected to the output port 9D of the optical coupler 9. Further, the optical filter 12 for removing the time division multiplexed signal light is one of the output ports 9C and 9D of the optical coupler 9,
It may be connected to the output port to which the optical multiplexer 6 is not connected. The local light source 10 in this embodiment may have the structure shown in FIGS. The wavelengths of local light λ1, λ2, ..., λN do not necessarily have to be different. In the structure of the network, for example, when performing routing by wavelength, in a structure in which a plurality of channels are distributed to the same route, the plurality of channels are set to have the same wavelength.

Also in this embodiment, as shown as the second embodiment of the all-optical type time division optical pulse demultiplexing circuit, the TDM which does not depend on the polarization state of the input time division multiplexed signal light is used.
-WDM conversion can be realized. (Embodiment of All-Optical Time Division Channel Drop Circuit) FIG.
Shows an embodiment configuration of an all-optical time division channel drop circuit of the present invention.

The feature of this embodiment is that in the configuration of the first embodiment of the all-optical time division optical pulse demultiplexing circuit shown in FIG.
The selected low-order group signal channel is input to the input port 9 of the optical coupler 9 by using the local oscillation light source 13 that outputs local oscillation light having a predetermined wavelength in synchronization with the extracted low-order group signal channel.
The output is from B. Furthermore, in order to send out the time division multiplexed signal light input from the transmission line to the transmission line again,
An optical demultiplexer 14 for demultiplexing the time division multiplexed signal light of wavelength λs is connected to the output port 9D of the optical coupler 9.

In this embodiment, low-order group signal channels of channels 1, 2, and 4 are extracted, and wavelengths λ1 and
Local light of λ2 and λ4 is input in synchronization with each low-order group signal channel. At the input port 9B of the optical coupler 9, the wavelength λ1,
Local light of λ2, λ4 is intensity-modulated by the low-order group signal channels of channels 1, 2, 4 and output. When separating this into each channel, an optical demultiplexer similar to the optical demultiplexer 7 in the all-optical time division optical pulse demultiplexing circuit may be connected.

The wavelengths of the local oscillation light used for the channel drop do not necessarily have to be different. The same wavelength may be included if necessary. That is, an arbitrary channel can be converted to an arbitrary wavelength and extracted by changing the configuration of local light. FIG. 15 shows the configuration of the first embodiment of the local oscillation light source 13.

The local light source 13 shown in (a) has wavelengths λ1, λ2,
It is composed of light sources 41-1 to 41-3 for outputting local light of λ4, optical delay devices 42-1 to 42-3 corresponding to the respective light sources, and an optical multiplexer 43 with three inputs and one output. Local light of each wavelength is transmitted through the optical delay devices 42-1 to 42-3 to the channels 1, 2,
An appropriate delay is given so as to overlap the 4th-order group signal channel on the time axis, and the multiplexed signal is output by the optical multiplexer 43. Note that the correspondence relationship between each low-order group signal channel and the wavelength of local oscillation light is arbitrary. That is, it is not necessary to set the wavelengths of the local oscillation lights to λ1, λ2, and λ4, respectively, in order to extract the low-order group signal channels of channels 1, 2, and 4, and they can be set freely.

(B) and (c) show light sources which replace the light sources 41-1 to 41-3. The light source shown in (b) is a broadband light source 44 that outputs white pulsed light having a sufficiently wide spectrum including wavelengths λ1 to λ4, and wavelengths λ1, λ from the white pulsed light.
It is composed of a 1-input / 3-output optical demultiplexer 45 which demultiplexes and outputs local light of 2, λ4. The optical demultiplexer 45 is compatible with the configuration shown in FIG.

The light source shown in (c) is a multi-wavelength light source 46 that simultaneously outputs optical pulses of wavelengths λ1, λ2, and λ4, and local light of wavelengths λ1, λ2, and λ4 is demultiplexed from this multi-wavelength pulsed light. It is composed of an optical demultiplexer 45 with one input and three outputs for outputting. The optical demultiplexer 45 is compatible with the configuration shown in FIG. FIG.
Shows the configuration of the second embodiment of the local light source 13.

The local light source 13 of this embodiment is a multi-wavelength light source 4
6 and the wavelength dispersion medium 47 are connected. The multi-wavelength pulsed light of wavelengths λ1, λ2, λ4 output from the multi-wavelength light source 46 corresponds to each wavelength so as to overlap with the low-order group signal channels of channels 1, 2, and 4 in the wavelength dispersion medium 47 on the time axis. Delay is given, and the local light pulse train is output. Therefore, it is necessary to use the wavelength corresponding to the time position of the extracted low-order group signal channel for the local oscillation light in this embodiment as shown in FIG.

Also in this embodiment, as shown as the second embodiment of the all-optical type time division optical pulse demultiplexing circuit, channel drop which does not depend on the polarization state of the input time division multiplexed signal light can be realized. .

[0050]

As described above, the all-optical time-division optical pulse demultiplexing circuit of the present invention is capable of simultaneously demultiplexing the low-order group signal channels constituting the time-division multiplexed signal light. As a result, the circuit configuration can be greatly simplified, and the ultrafast optical pulse demultiplexing circuit using the all-optical circuit can be stably operated.

In the all-optical time-division optical pulse demultiplexing circuit of the present invention, the time-division multiplexed signal light is demultiplexed into N low order group signal channels and, at the same time, converted into each wavelength of the local oscillation pulse train. Therefore, it is possible to function as a TDM-WDM conversion circuit by outputting each low-order group signal channel without separating it. Further, by changing the configuration of the local oscillation pulse train variously, it is possible to extract a plurality of specific low-order group signal channels. In this case, it can be made to function as an all-optical time division channel drop circuit that operates at an ultrahigh speed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of a first embodiment of an all-optical time division optical pulse demultiplexing circuit of the present invention.

FIG. 2 is a diagram showing a relationship between time division multiplexed signal light and local light in the all-optical time division optical pulse demultiplexing circuit of the present invention.

FIG. 3 is a diagram showing a relationship between time division multiplexed signal light and local light in the all-optical type time division optical pulse demultiplexing circuit of the present invention.

FIG. 4 is a diagram showing a configuration example of an optical demultiplexer 7.

FIG. 5 is a block diagram showing a configuration of a first embodiment of a local light source 10.

FIG. 6 is a block diagram showing the configuration of a second embodiment of the local light source 10.

7 is a block diagram showing the configuration of a third embodiment of the local light source 10. FIG.

FIG. 8 is a diagram showing the configuration of a first embodiment of a local oscillator light source that generates local oscillator light having linear chirping.

FIG. 9 is a diagram showing the configuration of a second embodiment of a local oscillator light source that generates local oscillator light having linear chirping.

FIG. 10 is a block diagram showing a configuration of a second embodiment of the all-optical time division optical pulse demultiplexing circuit of the present invention.

FIG. 11 is a block diagram showing a configuration of an embodiment of an all-optical TDM-WDM conversion circuit of the present invention.

FIG. 12 is a diagram showing a relationship between time division multiplexed signal light and local light in the all-optical TDM-WDM conversion circuit of the present invention.

FIG. 13 is a block diagram showing the configuration of an embodiment of the all-optical time division channel drop circuit of the present invention.

FIG. 14 is a diagram showing the relationship between time division multiplexed signal light and local light in the all-optical time division channel drop circuit of the present invention.

FIG. 15 is a block diagram showing the configuration of a first embodiment of a local light source 13.

FIG. 16 is a block diagram showing the configuration of a second embodiment of the local light source 13.

FIG. 17 is a block diagram showing a configuration example of a conventional all-optical time division optical pulse demultiplexing circuit.

[Explanation of symbols]

 1 Wavelength Dependent Optical Coupler 2,6 Optical Multiplexer 3,7,14 Optical Demultiplexer 4 Optical Kerr Medium 5 Optical Circulator 8 Optical Amplifier 9 Optical Coupler 10,13 Local Light Source 11 Birefringence Compensation Means 12 Optical Filter

Claims (7)

[Claims] 1. An optical amplifying means for inputting time-division multiplexed signal light of wavelength λs obtained by time-division-multiplexing N (N is an integer of 2 or more) low-order group signal channels, amplifying to a predetermined intensity, and outputting the amplified signal. A local light source for generating local light pulse trains having mutually different wavelengths λ1, λ2, ..., λN in synchronization with each low-order group signal channel of the time division multiplexed signal light; 2 × 2 optical coupling means for inputting into one input port of the optical coupling means and branching into two output ports in a one-to-one relationship; an optical Kerr medium coupling between two output ports of the optical coupling means; An optical multiplexing unit that multiplexes the time division multiplexed signal light output from the optical amplifying unit into a local oscillation pulse train branched to one output port and inputs the multiplexed light to the optical Kerr medium, and propagated through the optical Kerr medium. From light to each low order group signal channel of the time division multiplexed signal light The corresponding wavelength λ1, λ2, ...,
An all-optical time-division optical pulse demultiplexing circuit, which is equipped with an optical demultiplexing unit for demultiplexing local light of λ N and outputting to a port corresponding to each wavelength. 2. The optical frequency is synchronized with each low-order group signal channel of the time division multiplexed signal light in place of the local light source of the all-optical time division optical pulse demultiplexing circuit according to claim 1. All-optical time-division optical pulse multiplexing having a local oscillator source for generating local oscillator having a time width including N low-order group signal channels and having a linearly varying chirping Separation circuit. 3. The all-optical time-division optical pulse demultiplexing circuit according to claim 1, wherein the optical Kerr medium has birefringence and compensates for polarization dispersion between the two principal axes. The local light source is configured to generate a local light pulse train having a polarization in which the polarization components in the two orthogonal principal axis directions of the optical Kerr medium having the birefringence have the same intensity. An all-optical time-division optical pulse demultiplexing circuit characterized by the fact that 4. An optical amplifying means for inputting a time-division multiplexed signal light of wavelength λs obtained by time-division multiplexing N (N is an integer of 2 or more) low-order group signal channels, amplifying it to a predetermined intensity, and outputting it. A local light source for generating local light pulse trains having mutually different wavelengths λ1, λ2, ..., λN in synchronization with each low-order group signal channel of the time division multiplexed signal light; 2 × 2 optical coupling means for inputting into one input port of the optical coupling means and branching into two output ports in a one-to-one relationship; an optical Kerr medium coupling between two output ports of the optical coupling means; An optical multiplexing unit that multiplexes the time division multiplexed signal light output from the optical amplifying unit into a local oscillation pulse train branched to one output port and inputs the multiplexed light to the optical Kerr medium, and propagated through the optical Kerr medium. From the light, the time division multiplexed signal light is removed, and wavelengths λ1, λ2, ..., All-Optical TDM to the local light N is characterized in that an optical demultiplexing means for outputting a wavelength division multiplexed signal light in place of the time-division multiplexed signal light
-WDM conversion circuit. 5. The all-optical TDM-WDM according to claim 4.
In the conversion circuit, the optical Kerr medium has birefringence and includes birefringence compensating means for compensating for polarization dispersion between the two principal axes thereof, and the local light source emits the optical Kerr medium having the birefringence. An all-optical TDM-WDM conversion circuit, which is configured to generate a local oscillation pulse train having polarized waves in which polarization components in two orthogonal main axis directions have the same intensity. 6. An optical amplifying means for inputting time-division multiplexed signal light of wavelength λs obtained by time-division multiplexing N (N is an integer of 2 or more) low-order group signal channels, amplifying to a predetermined intensity, and outputting the amplified signal light. And local oscillation light that generates local oscillation pulse trains each having a predetermined wavelength in synchronization with M (M is an integer of 2 or more and N or less) low-order group signal channels to be separated among the time-division multiplexed signal lights. A source, the 2 × 2 optical coupling means for inputting the local oscillation pulse train to the first input port and branching the output light into two output ports in a one-to-one manner, and coupling between the two output ports of the optical coupling means. The optical Kerr medium, and an optical multiplexer that multiplexes the time-division multiplexed signal light output from the optical amplification unit with the local oscillation pulse train branched to one output port of the optical coupling unit and inputs the optical Kerr medium. Means and from the light propagating through the optical Kerr medium, Multiplexed signal light, the M all-optical time-division channel drop circuit, characterized in that an optical demultiplexing means for demultiplexing a local light corresponding to the low order group signal channel. 7. The all-optical type time-division channel drop circuit according to claim 6, wherein the optical Kerr medium has a birefringence and a birefringence compensating means for compensating for polarization dispersion between the two principal axes. The local light source is configured to generate a local light pulse train having a polarized wave in which polarization components in two orthogonal principal axis directions of the optical Kerr medium having the birefringence have the same intensity. All-optical time division channel drop circuit.