WO2020073250A1 - Optical add drop multiplexer and optical signal processing method - Google Patents

Abstract

The present application relates to the technical field of optical communications, and embodiments of the present application provide an optical add drop multiplexer and an optical signal processing method. The optical add drop multiplexer comprises: multiple cascaded filter units, each filter unit comprising: two port waveguides and multiple micro-rings located between the two port waveguides; wherein each port waveguide is coupled with one micro-ring of multiple micro-rings; a TC is provided between each port waveguide and the coupled micro-ring, and is used for adjusting a coupling coefficient between the port waveguide and the coupled micro-ring; each filter unit further comprises: at least one MEMS coupler, each MEMS coupler being used for adjusting a coupling coefficient between two adjacent micro-rings in multiple micro-rings; the TC and the MEMS coupler in each filter unit are used for adjusting a filter spectral pattern of the filter unit into a target filter spectral pattern, so that the optical add drop multiplexer can download/upload optical signals having different types of filter spectral patterns.

Description

Optical add-drop multiplexer and optical signal processing method Technical field

The present application relates to the technical field of optical communication, in particular to an optical add-drop multiplexer and an optical signal processing method.

Background technique

At present, optical wavelength add multiplexer (Optical Add Add Drop Multiplexer, OADM) is used in Wavelength Division Multiplexing (WDM) system of optical communication network to download / upload optical signals of any wavelength in WDM signals to achieve different Separation / aggregation of optical signals of wavelength. The resonant wavelength of the micro-ring has a linear relationship with the effective refractive index of the micro-ring waveguide. The effective refractive index of the micro-ring waveguide can be changed by the thermo-optic effect or the electro-optic effect, thereby changing the resonant wavelength of the micro ring. Therefore, tunable OADM can be realized by changing the resonance wavelength of the microring.

In the current WDM system, once the structure of OADM is determined, its filter spectrum type is also fixed. In other words, the optical add-drop multiplexer can only download / upload a fixed type of optical signal. With the expansion of the optical communication network, there will be a need to transmit optical signals of different filter spectrum types in each transmission node. At this time, each transmission node needs to be configured with multiple OADMs, which can download / upload optical signals of different types of filter spectrum types. This scheme of configuring multiple OADMs will lead to a higher complexity of the optical communication network and more difficult maintenance of the nodes.

Summary of the invention

The present application provides an optical add-drop multiplexer and an optical signal processing method, which can solve the problems of high complexity and difficult maintenance of the current optical communication network.

In a first aspect, an optical add-drop multiplexer is provided, including: a plurality of cascaded filter units, wherein:

Each of the filtering units includes: two port waveguides, and a plurality of microrings located between the two port waveguides;

Each of the port waveguides is coupled to one of the plurality of microrings, and a tunable coupler (TC) is provided between each of the port waveguides and the coupled microrings. The TC is used to adjust the coupling coefficient between the port waveguide and the coupled microring;

Each of the filtering units further includes: at least one microelectromechanical system MEMS coupler, and each of the MEMS couplers is used to adjust a coupling coefficient between two adjacent microrings in the plurality of microrings;

Any two adjacent filter units are connected by a port waveguide;

The TC and MEMS couplers in each filter unit are used to adjust the filter spectrum of the filter unit to the target filter spectrum.

By adjusting the TC and MEMS coupler to change the coupling coefficient between every two coupled waveguides in the filter unit, the filter spectrum type supported by the filter unit can be adjusted, so that the optical add / drop multiplexer can be downloaded / Upload optical signals of different types of filtered spectrum. Using the OADM of the present application, it is possible to download / upload optical signals of different types of filter spectra without configuring multiple OADMs in each transmission node, which effectively reduces the complexity of the optical communication network and reduces the transmission The operation and maintenance of the OADM configured in the node. Further, in each filter unit, the coupling coefficient between the two coupled microrings is adjusted by the MEMS coupler, and will not affect the resonance wavelength of the microrings. There is no mutual influence between the adjustment of the filter spectrum type of the filter unit and the adjustment of the resonance wavelength of the micro ring, and there is no need to establish the correspondence between the different filter spectrum types of the filter unit and the different resonance wavelength of the micro ring, which effectively reduces the Cost of optical add-drop multiplexer.

Optionally, the two port waveguides include: a first port waveguide having an input port and a through port, and a second port waveguide having a download port and an upload port;

The TC in each of the filter units is also used to control all optical signals input from the input port of the first port waveguide to be transmitted to the through port of the first port waveguide.

In the embodiment of the present application, if the difference between the current filter spectrum type of the filter unit and the target filter spectrum type is large, all optical signals input from the input port of the first port waveguide can be transmitted to its through port through TC control; Then adjust the current filter spectrum to the target filter spectrum through the TC and MEMS coupler. This effectively prevents the filtering unit from affecting the filtering performance of other filtering units during the process of adjusting the filtering spectrum.

In addition, when the optical signal to be downloaded is switched from the optical signal of the current wavelength to the optical signal of the target wavelength, all optical signals input from the input port of the first port waveguide are transmitted to its through port through TC control. After the switching is completed, Then control the channel to be in the optical signal download state, so that the channel can download the optical signal of the target wavelength, effectively avoiding the download port outputting the optical signal of the wavelength between the target wavelength and the current wavelength during the switching process, and avoiding the loss of signal The loss of optical signal transmission in the optical add-drop multiplexer is reduced. In addition, this method makes the optical add-drop multiplexer have the function of non-blocking wavelength switching.

Optionally, every two adjacent microrings in the plurality of microrings are coupled through a coupling waveguide in each microring; each MEMS coupler includes: each of the two coupled microrings A coupling waveguide in the microring and a displacement adjustment component; at least one of the coupling waveguides of the two coupled microrings is a suspension waveguide; the displacement adjustment component is used to control the movement of the suspension waveguide to adjust the Coupling coefficient between two coupled microrings.

Optionally, the multiple microrings are composed of deep waveguides or shallow-etched waveguides.

In the embodiment of the present application, the coupling coefficient between the two coupled microrings is related to the spatial distance between the two coupled waveguides in the two coupled microrings. When the displacement adjustment component controls the movement of the suspended waveguide, The coupling coefficient between the two coupled microrings can be adjusted.

Optionally, every two adjacent microrings in the plurality of microrings are coupled through a coupling waveguide in each microring; each MEMS coupler includes: each of the two coupled microrings Coupling waveguide, cantilever and displacement adjustment assembly in the microring; the orthographic projection of the cantilever on the two coupled microrings has an overlapping area with each coupling waveguide in the two coupled microrings Or, the orthographic projection of the cantilever on the two coupled microrings is between the two coupled microrings; the refractive index of the cantilever is greater than that between the two coupled microrings The refractive index of the filler; the displacement adjustment component is used to control the cantilever to move toward or away from the coupling waveguide to adjust the coupling coefficient between the two coupled microrings. In other words, the projection of the cantilever should cover the coupling interval formed by the coupling waveguides of the two coupling microrings and the gap between the two coupling waveguides, and can cover all or part of the coupling interval.

In this application, the coupling coefficient between the two coupled microrings is related to the effective refractive index in the coupled waveguide. When the cantilever is controlled to move closer or away from the coupled waveguide by the displacement adjustment component, the transmission in the coupled waveguide will be changed. The effective refractive index of the optical signal, thereby changing the coupling coefficient between two coupled microrings.

Optionally, the optical add-drop multiplexer further includes: an input-output pre-processing unit and a plurality of merging and separating units, and the plurality of merging and separating units correspond to the plurality of cascaded filtering units in one-to-one correspondence; The first light wave transmission port of the input and output preprocessing unit is connected to the input port of the first filter unit, and the second light wave transmission port of the input and output preprocessing unit is connected to the through port of the last filter unit; The two light wave transmission ports of the separation unit are respectively connected to the upload port and download port of the corresponding filter unit.

Optionally, each of the merging and separating units includes: a first polarization beam splitter rotator PSR, a second PSR, a first input-output splitter and a second input-output splitter; the first input-output splitter and all The second input-output splitter each has an input end, an output end, and an optical wave transmission port, and both the first PSR and the second PSR have an optical wave transmission port, an optical wave beam splitting port, and an optical wave beam splitting rotating port; Convergence and separation unit: the input port of the first input-output splitter is connected to the upload port of the corresponding filtering unit, and the output port of the first input-output splitter is connected to the optical beam splitting port of the first PSR. The optical wave transmission port of the first input-output splitter is connected to the optical beam splitting rotation port of the second PSR, the input port of the second input-output splitter is connected to the download port of the corresponding filter unit, and the second The output port of the input-output splitter is connected to the optical wave splitting rotation port of the first PSR, and the optical wave transmission port of the second input-output splitter is connected to the light of the second PSR Beam port.

Optionally, the input-output pre-processing unit includes: a third input-output separator, a fourth input-output separator, a third PSR, and a fourth PSR; the third input-output separator and the fourth input-output Each splitter has an input end, an output end, and an optical wave transmission end, and the third PSR and the fourth PSR each have an optical wave transmission port, an optical wave beam splitting port, and an optical wave beam splitting rotating end; the third input-output splitter Is connected to the input port of the first filtering unit, the output port of the third input-output splitter is connected to the optical beam splitting port of the fourth PSR, and the optical wave of the third input-output splitter The transmission port is connected to the optical beam splitting rotation port of the third PSR, the input port of the fourth input-output splitter is connected to the through port of the last filtering unit, and the output port of the fourth input-output splitter It is connected to the optical wave splitting rotation port of the fourth PSR, and the optical wave transmission port of the fourth input-output splitter is connected to the optical wave splitting port of the third PSR.

Optionally, the multiple cascaded filtering units and the multiple converging and separating units are used to implement uploading and downloading of optical signals of multiple channels, in each of the channels:

When the channel is in the optical signal download state, the input-output pre-processing unit is used to process the input optical signal into Q _TE and P _TE and transmit it to the multiple cascaded filter units, where Q _TE represents the transverse electric field TE mode optical signal, P _TE means that the transverse magnetic field TM mode optical signal is rotated into TE mode optical signal; the filtering unit is used to convert the first Q _TE of the specified wavelength in the Q _TE , and the P The first P _TE of the specified wavelength in the _{TE is} transmitted to the corresponding merging and separating unit; the merging and separating unit is used for merging the received first Q _TE and the first P _TE to output;

When the channel is in an optical signal uploading state, the converging and separating unit is used to process the input optical signal into a second Q _TE and a second P _TE , and the second Q _TE and the second P _TE It is transmitted to the input-output preprocessing unit through the corresponding channel.

Optionally, the input-output pre-processing unit is further configured to receive Q _TE and P _TE output from the plurality of cascaded filtering units, and output the received Q _TE and P _TM after merging.

Through the input-output pre-processing unit and the separation and merging unit, only one polarization mode optical signal can be transmitted in the waveguide of the optical add-drop multiplexer, thereby avoiding the difference between the two polarization mode optical signals transmitted in the same waveguide The bigger problem.

Optionally, the optical add-drop multiplexer further includes: another set of multiple cascaded filter units, input-output pre-processing units, multiple separation units, and multiple merge units, the multiple separation units, all The plurality of merging units, a group of multiple cascaded filter units and another group of multiple cascaded filter units are in one-to-one correspondence; the first light wave transmission port of the input-output preprocessing unit is respectively associated with a group of multiple stages The input port of the first filter unit in the cascaded filter unit, and the input port of the first filter unit in another set of multiple cascaded filter units, the second light wave transmission of the input and output preprocessing unit The ports are respectively connected to the through port of the last filter unit in a group of multiple cascaded filter units, and the through port of the last filter unit in another group of multiple cascaded filter units; each of the merging units The light wave transmission port is connected to the download port of the corresponding filter unit in a group of multiple cascaded filter units, and the download port of the corresponding filter unit in another group of multiple cascaded filter units Connection; the light wave transmission port of each of the separation units is respectively uploaded to the upload port of the corresponding filter unit in a group of multiple cascaded filter units, and the upload of the corresponding filter unit in another group of multiple cascaded filter units Port connection.

Optionally, the input-output pre-processing unit includes: a first optical wave beam splitter PBS and a second PBS; both the first PBS and the second PBS have an optical wave transmission port, a first optical wave beam splitting port and a second optical wave Beam splitting port; the first optical wave splitting port of the first PBS is connected to the input port of the first filtering unit in the set of multiple cascaded filtering units, and the second optical wave splitting of the first PBS The beam port is connected to the input port of the first filter unit in the other set of multiple cascaded filter units, and the first light beam splitting port of the second PBS is connected to the set of multiple cascaded filters The through port in the last filtering unit in the unit is connected, and the second optical wave splitting port in the second PBS is connected to the through port in the last filtering unit in the other plurality of cascaded filtering units.

Optionally, each of the confluence units includes a third PBS, and each of the separation units includes a fourth PBS; the third PBS and the fourth PBS each have an optical wave transmission port, a first optical wave beam splitting port, and A second light wave beam splitting port; the first light wave beam splitting port of the third PBS is connected to a download port of a corresponding filter unit in a group of multiple cascaded filter units, and the second light wave beam splitting of the third PBS The port is connected to the download port of the corresponding filter unit in another group of multiple cascaded filter units; the first light beam splitting port of the fourth PBS is connected to the corresponding filter unit in the group of multiple cascaded filter units The upload port is connected, and the second optical wave splitting port of the fourth PBS is connected to the upload port of the corresponding filter unit in another set of multiple cascaded filter units.

Optionally, it is characterized in that two sets of multiple cascaded filter units, the multiple separation units and the multiple merge units are used to realize the upload and download of multiple channels of optical signals, and each of the channels in:

When the channel is in the optical signal download state, the input-output preprocessing unit is used to process the input optical signal into Q _TE and P _TM , and transmit the processed Q _TE and P _TM to the two respectively a plurality of cascade filtering unit, wherein, P represents _TM TM mode optical signal; a first filtering unit for the Q _TE third specified wavelength to a corresponding transmission Q _TE confluence unit; second filtering unit It is used to transmit the third P _TM of the specified wavelength in the P _TM to the corresponding merging unit; the merging unit is used to merge the received third Q _TE and the third P _TM for output;

When the channel is in an optical signal uploading state, the separation unit is used to process the input optical signal into a fourth Q _TE and a fourth P _TM , and pass the fourth Q _TE and the fourth P _TM through The corresponding channel is transmitted to the input and output preprocessing unit;

Wherein, the first filtering unit is one filtering unit in a group of multiple cascaded filtering units, and the second filtering unit is a filtering unit corresponding to the first filtering unit in another group of multiple filtering units .

Alternatively, the input and output pre-processing unit further configured to receive from a plurality of sets of filter units are cascaded output Q _TE and P _TM, and outputs the received P _TM and Q _TE for convergence.

Through the input and output preprocessing unit, separation unit and merging unit, only one polarization mode optical signal can be transmitted in the waveguide in the optical add-drop multiplexing, thus avoiding the occurrence of the two polarization mode optical signals transmitted in the same waveguide Time difference is a big problem.

Optionally, each of the TCs includes: a first sub-waveguide in the port waveguide, a second sub-waveguide in a microring coupled to the port waveguide, and a first sub-waveguide provided on the first sub-waveguide A first phase controller PS, which is used to adjust the phase difference between the optical signal transmitted in the first sub-waveguide and the optical signal transmitted in the second sub-waveguide.

Optionally, a second PS is further provided on each of the micro-rings, and the second PS is used to adjust the resonance wavelength of the micro-ring, wherein, in each of the filtering units, the second PS , The TC and the MEMS coupler do not have overlapping areas.

According to a second aspect, an optical signal processing method is provided. The method is applied to the optical add / drop multiplexer according to any one of the first aspects. The method includes:

Adjusting the TC and MEMS coupler in each of the filtering units to adjust the filtering spectrum of the filtering unit to the target filtering spectrum.

Optionally, the adjusting the TC and MEMS coupler in each filter unit to adjust the filter spectrum of the filter unit to the target filter spectrum includes:

When each of the filtering units is in an optical signal uploading state or an optical signal downloading state, the TC and the MEMS coupler are adjusted to adjust the filtering spectrum of the filtering unit to the target filtering spectrum.

Optionally, the two port waveguides include: a first port waveguide having an input port and a through port, and a second port waveguide having a download port and an upload port;

The adjusting the TC and MEMS couplers in each of the filtering units to adjust the filtering spectrum of the filtering unit to the target filtering spectrum includes:

Controlling the TC provided between the first port waveguide and the coupled microring, so that all optical signals input from the input port of the first port waveguide are transmitted to the through port of the first port waveguide;

Controlling the TC provided between the second port waveguide and the coupled micro ring to adjust the coupling coefficient between the second waveguide and the coupled micro ring, and controlling each of the MEMS couplers to adjust the Coupling coefficient between two adjacent microrings in multiple microrings;

Controlling the TC provided between the first port waveguide and the coupled micro ring to adjust the coupling coefficient between the first waveguide and the coupled micro ring, so that the filtering spectrum of the filtering unit is adjusted to Target filter spectrum.

It should be noted that, for the principle of the optical signal processing method in the second aspect, reference may be made to the corresponding part of the structure of the optical add-drop multiplexer in the first aspect, which will not be repeated here.

The beneficial effect of the technical solution provided by the present application is that in each filter unit, the coupling coefficient between every two coupled waveguides in the filter unit is changed by adjusting the TC and the MEMS coupler, so as to achieve the The adjustment of the filter spectrum type enables the optical add-drop multiplexer to download / upload optical signals of different types of filter spectrum types. If the optical add / drop multiplexer is configured in the transmission node of the optical communication network, it is possible to download / upload different types of optical filter types without configuring multiple optical add / drop multiplexers in each transmission node The signal effectively reduces the complexity of the optical communication network and reduces the difficulty in operating and maintaining the optical add-drop multiplexer configured in the transmission node.

BRIEF DESCRIPTION

Figure 1 is a schematic diagram of a micro-ring interpolation filter;

2 is a schematic structural diagram of a micro-loop interpolation filter with TC provided by an embodiment of the present application;

3 is a schematic structural diagram of an optical add-drop multiplexer provided by an embodiment of the present application;

FIG. 4 shows an example diagram of the filter spectrum types of the three filter units in Table 1;

5 is a schematic structural diagram of a filtering unit provided by an embodiment of the present application;

Figure 6 is a cross-sectional view of Figure 5 at A-A ';

7 is another cross-sectional view of FIG. 5 at A-A ’,

8 is a schematic structural diagram of another filtering unit provided by an embodiment of the present application;

9 is a cross-sectional view of FIG. 8 at A-A ';

10 is another cross-sectional view of FIG. 8 at A-A ';

11 is a schematic structural diagram of another optical add-drop multiplexer provided by an embodiment of the present application;

FIG. 12 shows an optical path diagram when the channels in the optical add / drop multiplexer shown in FIG. 11 are in the state of downloading optical signals;

FIG. 13 shows an optical path diagram when the channels in the optical add-drop multiplexer shown in FIG. 11 are in an optical signal uploading state;

14 is a schematic structural diagram of yet another optical add-drop multiplexer provided by an embodiment of the present application;

15 shows an optical path diagram when the channels in the optical add-drop multiplexer shown in FIG. 14 are in the state of downloading optical signals;

FIG. 16 shows an optical path diagram when the channels in the optical add / drop multiplexer shown in FIG. 14 are in the optical signal uploading state.

detailed description

Before explaining the embodiments of the present application in detail, the structure and functions of the optical device involved in the embodiments of the present application will be briefly introduced.

(1) Micro-ring interpolation filter

As shown in FIG. 1, the micro-ring add / drop filter includes two parallel straight waveguides and a micro-ring R located between the two straight waveguides. The micro-ring R is composed of one or more ring waveguides. The microring add-drop filter includes four ports, namely an input port, a through port, a download port and an upload port. For ease of explanation, in FIG. 1 and the following embodiments, the four ports are respectively labeled as i, t, d, and a in sequence. It should be noted that the add-drop filter is also called an add-drop filter (Add Drop Filter, ADF).

Part of the optical signal that satisfies the resonance condition of the micro ring in the optical signal input from the i port will be coupled to the micro ring R and output from the d port, and other optical signals will be output from the t port. This process is called optical signal download. Part of the wavelength of the optical signal input from the a port that satisfies the microring resonance condition is coupled to the microring R and output from the t port, while other optical signals that do not meet the microring resonance condition are output from the d port. The process is called uploading of optical signals.

(2) Tunable coupler (TC)

FIG. 2 is a schematic structural diagram of a micro-loop interpolation filter with TC provided by an embodiment of the present application. Among them, TC has the function of adjusting the energy of the optical signal input to the ring waveguide in the micro-ring add / drop filter. Replace a straight waveguide in the micro-ring add / drop filter in FIG. 1 with a bent waveguide, so that the bent waveguide has a certain length difference ΔL from the ring waveguide in the micro-loop add / drop filter = 2πR ₀ . Among them, R ₀ is the radius of the ring waveguide, and a phase controller (Phase Shifter, PS) is provided on the bent waveguide, that is, a micro-loop interpolation filter with TC is formed. When the optical signal is input from the input port i, the PS is controlled to adjust the energy ratio (also called coupling coefficient) of the optical signal coupled to the microring R by the optical signal. When the phase of the optical signal transmitted in the waveguide is adjusted by the PS, so that the optical signal input from the input port i is all output from the through port t, the micro-ring interpolation filter will not produce a filtering effect on the optical signal; when the waveguide is adjusted by the PS The phase of the optical signal transmitted in is to make the optical signal satisfying the micro-ring resonance condition in the optical signal input from the input port i coupled to the micro-ring R, the micro-ring add-drop filter can produce a filtering effect on the optical signal.

(3) Input and output splitter

The input-output splitter refers to an optical device that separates the input port and the output port of the optical signal. The input-output splitter may be a multi-port circulator or a multi-port coupler. When the input-output splitter is a three-port circulator, the three-port circulator includes three ports, namely an input port, a light wave transmission port, and an output port. The function of the three-port circulator is to output the optical signal input to any one of the three ports from the next port in a certain direction order. It should be noted that the order of the certain directions may be clockwise or counterclockwise.

(4) Polarization beam splitter (Polarization splitter and rotator, PSR)

PSR refers to an optical device that can simultaneously perform polarization beam splitting processing and polarization rotation processing on an optical signal. The PSR includes three ports, namely an optical wave transmission port, an optical wave beam splitting rotating port, and an optical wave beam splitting port.

When an optical signal is input from the optical wave transmission port of the PSR, the PSR performs polarization beam splitting processing on the input optical signal to obtain Q _TE and P _TM , and Q _TE represents an optical signal in the Transverse Electric (TE) mode, P _TM An optical signal representing a Transverse Magnetic (TM) mode. The PSR outputs Q _TE from the optical beam splitting port, and at the same time rotates the P _{TM of} the optical signal into an optical signal whose polarization mode is TE mode, that is, rotates P _TM into P _TE , P _TE means that the optical signal in TM mode is rotated into TE mode Optical signal, and output P _TE from PSR's optical beam splitting rotary port.

When the PSR receives P _TE from the optical beam splitting rotation port and Q _TE from the optical beam splitting port, the PSR rotates the P _TE into an optical signal whose polarization mode is the TM mode, that is, rotates Q _TE to Q _TM , and P _TE and Q _TM for confluence, then merge the lightwave transmission from the output port of the PSR P _TE and Q _TM.

(5) Polarization beam splitter (Polarization beam splitter, PBS)

PBS refers to an optical device that can polarize and split optical signals. The PBS includes three ports, namely an optical wave transmission port, a first optical wave beam splitting port and a second optical wave beam splitting port.

When an optical signal is input from the optical wave transmission port of PBS, PSR performs polarization beam splitting on the input optical signal to obtain Q _TE and P _TM , and separates them from the first optical wave splitting port and the second optical wave splitting port, respectively Output. When P _TE and P _TM are input from the first optical wave splitting port and the second optical wave splitting port of PBS, respectively, PBS merges P _TE and Q _{TM to} output through the optical wave transmission port.

FIG. 3 is a schematic structural diagram of an optical add-drop multiplexer provided by an embodiment of the present application. The optical add-drop multiplexer may include: a plurality of cascaded filter units 10. Each filter unit 10 includes two port waveguides (11a and 11b), and a plurality of microrings 12 located between the two port waveguides. Among them, any two adjacent filter units 10 are connected by a port waveguide (11a).

It should be noted that the embodiment of the present application takes the arrangement direction of the plurality of micro rings 12 (that is, the direction of the connection line of the center point of each micro ring in the plurality of micro rings) as an example perpendicular to the extending direction of the port waveguide Make a schematic description. In a specific implementation, the arrangement direction of the multiple microrings may be at a certain angle to the extending direction of the port waveguide, or the connection line of the center points of the multiple microrings is at least one of a curve and a polyline. In this regard, the embodiment of the present application is not limited, and it is only required that each port waveguide is coupled to one microring in the plurality of microrings 12.

A TC 13 is provided between each port waveguide and the coupled micro ring 12. The TC 13 is used to adjust the coupling coefficient between the port waveguide and the coupled micro ring 12. For example, each TC 13 may include: a first sub-waveguide 131 in the port waveguide, a second sub-waveguide 132 in the microring 12 coupled to the port waveguide, and a first sub-waveguide provided on the first sub-waveguide 131 PS 133. The first PS133 is used to adjust the phase difference between the optical signal transmitted in the first sub-waveguide 131 and the optical signal transmitted in the second sub-waveguide 132 to adjust the coupling between the port waveguide and the microring 12 coupled thereto coefficient.

Each filtering unit 10 further includes: at least one micro-electromechanical system (Micro Electro Mechanical System, MEMS) coupler 14. Each MEMS coupler 14 is used to adjust the coupling coefficient between two adjacent microrings in the plurality of microrings 12. It should be noted that every two adjacent microrings 12 in the plurality of microrings 12 are coupled. The number of MEMS couplers 14 is related to the number of multiple microrings 12, and every two coupled microrings 12 needs to be equipped with a MEMS coupler 14. For example, assuming that the number of the plurality of micro rings 12 is N, it is necessary to configure N-1 MEMS couplers 14.

In each filter unit 10, TC 13 and MEMS coupler 14 are adjustable components. By adjusting these two components, the filtering spectrum of the filtering unit 10 can be adjusted to the target filtering spectrum. The filter spectrum type of the target can be set according to actual needs. It should be noted that the filtering spectrum of the filtering unit includes: bandwidth, steepness of the falling edge, and width of the filtering flat top.

In the embodiment of the present application, the filter spectrum type of each filter unit 10 is determined by the coupling coefficient between every two coupled waveguides in the filter unit. The coupling coefficient between the two coupled waveguides includes: a port The coupling coefficient between the waveguide 11 and the coupled microring 12 and the coupling coefficient between the two coupled microrings 12. Through the adjustment of TC 13 and MEMS coupler 14, the coupling coefficient between every two coupled waveguides in the filter unit 10 can be adjusted to realize the adjustment of its filter spectrum, so that the optical add / drop multiplexer can be downloaded / Upload optical signals of different types of filtered spectrum.

Exemplarily, Table 1 shows the values of the coupling coefficient between the port waveguide and the coupled microrings configured by TC 13 in the filter unit 10, and the coupling coefficient between the two coupled microrings configured by the MEMS coupler 14 The numerical value corresponds to the bandwidth of the filtering spectrum of the filtering unit 10. FIG. 4 shows an example diagram of the filter spectrum types of the three filter units in Table 1. It should be noted that, in Table 1 and FIG. 4, the bandwidth of the filter spectrum is adjusted as an example for illustrative description.

Table 1

Configure the coupling coefficient between the port waveguide and the coupled microring through TC	0.51	0.48	0.444
Configure the coupling coefficient between two coupled microrings via MEMS coupler	0.146	0.12	0.078
Bandwidth unit of the filtering spectrum of the filtering unit: Kyrgyzstan (G)	100	75	50

For example, in the filter unit 10, when the coupling coefficient between the port waveguide and the coupled microrings is configured by TC 13 is 0.51, and the coupling coefficient between the two coupled microrings is configured by the MEMS coupler 14 as At 0.146, the bandwidth of the filtering spectrum of the filtering unit is 100G.

In the embodiment of the present application, the transmission node is configured with the optical add-drop multiplexer in the embodiment of the present application, and there is no need to configure multiple optical add-drop multiplexers to realize the downloading / uploading of optical signals of different types of filter spectra. , Effectively reduce the complexity of the optical communication network, and reduce the difficulty of operation and maintenance of the optical add-drop multiplexer configured in the transmission node.

The coupling coefficient between every two coupled waveguides in the optical add-drop multiplexer can be adjusted by TC. However, in the process of adjusting the coupling coefficient by TC (that is, the PS it contains), the resonance wavelength of the microring will be changed, resulting in the wavelength of the optical signal downloaded / uploaded by the optical add-drop multiplexer and the optical signal required by the WDM system The wavelength is different. In order to realize that the optical add / drop multiplexer can download / upload optical signals of different wavelengths in the optical signal of any filter spectrum type, it is necessary to establish the relationship between the different filter spectrum types of the optical add / drop multiplexer and the different resonance wavelengths of the microring Correspondence. However, the adjustment of the coupling coefficient will cause the resonance wavelength of the microring to change. Therefore, the corresponding relationship needs to be repeatedly debugged for the optical add-drop multiplexer to be established. The cost of the add / drop multiplexer increases.

In the embodiment of the present application, as shown in FIG. 3, the coupling coefficient between the two coupled micro-rings 12 is adjusted by the MEMS coupler 14 and will not affect the resonance wavelength of the micro-ring 12. There is no mutual influence between the adjustment of the filter spectrum type of the filter unit 10 and the adjustment of the resonance wavelength of the microring 12, and there is no need to establish the correspondence between the different filter spectrum types of the filter unit 10 and the different resonance wavelengths of the microring 12 Relationship, effectively reducing the cost of the optical add-drop multiplexer.

Optionally, as shown in FIG. 3, the two port waveguides 11 in each filter unit 10 include: a first port waveguide 11a having an input port i and a through port t, and a download port d and uploading The second port waveguide 11b of port a. Any two adjacent filter units 10 may be connected through the first port waveguide 11a. Illustratively, the through port t of the first port waveguide 11a in the previous filter unit 10 is connected to the input port i of the first port waveguide 11a in the latter filter unit 10. The TC in each filter unit 10 (the TC is the TC 13 provided between the first port waveguide 11a and the coupling microring 12) is also used to: control the transmission of all optical signals input from the input port i of the first port waveguide 11a The through port t to the first port waveguide 11a.

In the embodiment of the present application, assuming that the current filtering spectrum of a certain filtering unit 10a among the multiple cascaded filtering units 10 needs to be adjusted to the target filtering spectrum, then:

If the difference between the current filter spectrum type of the filter unit 10a and the target filter spectrum type is small, it will not affect the filter performance of other filter units during the adjustment process. At this time, the TC 13 and the MEMS coupler 14 in the filtering unit 10a can directly adjust the current filtering spectrum to the target filtering spectrum.

If a filter unit has a large difference between the current filter spectrum and the target filter spectrum, other filter units may have a signal loss problem during the adjustment process, which leads to the adjustment of a filter unit filter spectrum It has an impact on the filtering performance of other filtering units. To solve this problem, taking the filter unit 10a as an example, it is necessary to first control the TC 13 provided between the first port waveguide 11a and the coupled microring 12 so that all optical signals input from the input port i of the first port waveguide 11a Transmitted to its through port t; then through the MEMS coupler 14 in the filter unit 10a to adjust the coupling coefficient between the two coupled micro-rings 12, while at the same time through the second port waveguide 11b and the coupled micro-ring 12 set TC 13 Adjust the coupling coefficient between the two; Finally, adjust the coupling coefficient between the first port waveguide 11a and the coupled microring 12 to adjust the current filter spectrum to the target filter spectrum type. Doing so can effectively avoid affecting the filtering performance of other filtering units when adjusting the filtering spectrum of a certain filtering unit.

In the embodiment of the present application, as shown in FIG. 3, each filter unit 10 is provided with a second PS 121 on the micro ring 12. The second PS 121 is used to adjust the resonance wavelength in the micro-ring 12 so that the corresponding filter unit 10 can download / upload optical signals of different wavelengths. In each filter unit 10, there is no overlapping area between the second PS 121, TC 13, and the MEMS coupler 14. That is to say, in any microring 12, the waveguide provided with the second PS 121, the waveguide belonging to the TC 13, and the waveguide belonging to the MEMS coupler 14 are different waveguides.

When the downloaded optical signal of a certain filter unit 10a is switched from the optical signal of the current wavelength to the optical signal of the target wavelength, the TC 13 in the filter unit 10a first needs to control the input from the input port i of the first port waveguide 11a All optical signals are transmitted to the through port t of the first port waveguide 11a; the second PS 121 in the filter unit 10a is used to adjust the resonance wavelength of the microring 12. After the adjustment is completed, the filter unit 10a is controlled to download the optical signal of the target wavelength, which effectively avoids that the download port d of the filter unit 10a outputs the wavelength between the target wavelength and the current wavelength during the process of switching the wavelength of the downloaded optical signal Optical signals avoid signal loss and reduce the loss of optical signal transmission in optical add-drop multiplexers. In addition, the wavelength switching method makes the optical add-drop multiplexer have a non-blocking wavelength switching function. That is to say, in the process of switching the wavelength of the optical signal, the optical add-drop multiplexer will not affect the transmission of optical signals of other wavelengths.

In the embodiment of the present application, every two adjacent microrings in the multiple microrings are coupled through the coupling waveguide in each microring. In the two coupled microrings, the coupling waveguide of each microring is connected to another The coupling waveguides of the microring are adjacent. The structure of the MEMS coupler in the embodiments of the present application has multiple implementable modes, and the embodiments of the present application provide examples of the two implementable modes.

In the first realizable manner, the structure of the filtering unit 10 is shown in FIG. 5. Each MEMS coupler 14 includes: a coupling waveguide 141 in each micro ring 12 of the two coupled micro rings 12, and a displacement adjustment assembly 142. At least one of the two coupled waveguides 141 in the two coupled microrings 12 is a suspended waveguide 141a.

In the embodiment of the present application, the displacement adjusting component 142 can control the floating waveguide 141 a in the two coupled micro-rings 12 to change the spatial distance between the two coupled micro-rings 12. The coupling coefficient between the two coupled microrings 12 is related to the spatial distance between the two coupling waveguides 141 in the two coupled microrings. Therefore, controlling the movement of the suspended waveguide 141a by the displacement adjustment component 142 can change the coupling coefficient between the two coupled microrings 12.

Optionally, the plurality of microrings 12 in the filter unit 10 are composed of deep waveguides or shallow waveguides. For example, when each microring 12 is composed of a deep waveguide, FIG. 6 is a cross-sectional view at A-A 'in FIG. 5, and each microring 12 has a closed loop shape. When each microring 12 is composed of a shallow-etched waveguide, FIG. 7 is another cross-sectional view at A-A 'in FIG. 5, and each microring 12 has a disk shape. It should be noted that, in an optional implementation manner, each micro ring 12 in the plurality of micro rings 12 may be composed of a deep waveguide or a shallow waveguide; in another optional implementation manner Part of the plurality of micro-rings 12 is composed of deep waveguides, and the other part of the micro-rings is composed of shallow waveguides.

As shown in FIG. 6 or FIG. 7, each microring 12 and each port waveguide 11 in the filter unit 10 are made of a semiconductor substrate. Generally, the semiconductor substrate is a silicon-on-insulator (SOI) substrate. The semiconductor substrate includes a bottom semiconductor layer 20a, a buried oxide layer 20b, and a top semiconductor layer. The top semiconductor layer is used to manufacture each microring 12 and each port waveguide in the filter unit 10. In the embodiment of the present application, after each microring 12 and each port waveguide 11 are formed in the filter unit 10, a plurality of hollow regions 20b1 may be formed in the buried oxide layer 20b to make the suspended waveguide 141a in the microring 12 It is located directly above the hollow area 20b1, so that the suspended waveguide 141a can move within the corresponding hollow area 20b1 under the control of the displacement adjustment component.

Optionally, as shown in FIG. 6 or FIG. 7, a protection layer 20c may be provided on each microring 12 except for the region where the suspended waveguide 141a is located, and the material of the protection layer 20c may be silicon dioxide. The protective layer 20c can not only protect the micro ring 12 but also ensure the symmetry of the refractive index of the waveguide cladding on both sides of the micro ring 12. However, it is not necessary to provide a protective layer on the suspended waveguide 141a, so that the displacement adjustment assembly can more easily drive the suspended waveguide 141a to move.

In the second realizable manner, the structure of the filtering unit 10 is shown in FIG. 8. Each MEMS coupler 14 includes a coupling waveguide 141, a cantilever 143, and a displacement adjustment assembly 142 in each of the two coupled micro rings 12.

In a possible specific embodiment, as shown in FIG. 9, FIG. 9 is a cross-sectional view of FIG. 8 at AA ′, the orthographic projection of the cantilever 143 on the two coupled microrings 12, and the There is an overlapping area between each coupling waveguide 141 of the two coupled microrings 12. The refractive index of the cantilever 143 is greater than the refractive index of the filler between the two coupled micro rings 12. Specifically, the filling may be air or a solid filling medium.

In another possible specific embodiment, FIG. 10 is another cross-sectional view of FIG. 8 at A-A '. The orthographic projection of the cantilever 143 on the two coupled micro-rings 12 is located between the two coupled micro-rings 12. The refractive index of the cantilever 143 is greater than the refractive index of the filler between the two coupled micro rings 12. Specifically, the filling is air.

In practical applications, the effective refractive index of the waveguide is determined by the size of the waveguide, the refractive index of the waveguide core and the refractive index of the waveguide cladding. The body of the coupling waveguide 141 in the microring 12 corresponds to the waveguide core, and the cantilever 143 and the air between the cantilever 143 and the coupling waveguide 141 correspond to the waveguide cladding. After the microring 12 is formed, the size and refractive index of the coupled waveguide 141 are fixed. If the cantilever 142 is controlled to move closer or away from the coupled waveguide 141 by the displacement adjustment component 142, the refractive index of the waveguide cladding will change, thereby The effective refractive index in the coupling waveguide 141 is changed. The coupling coefficient between the two coupled microrings 12 is related to the effective refractive index of the coupled waveguide 141. Therefore, the displacement adjustment component 142 controls the cantilever 143 to move toward or away from the coupling waveguide 141 to change the coupling coefficient between the two coupled microrings 12.

For example, the displacement adjusting component 142 can control the cantilever 143 to move in a direction perpendicular to the micro ring 12 (that is, a direction perpendicular to the paper surface). Alternatively, the displacement adjustment component 142 may control the cantilever 143 to move toward or away from the coupling waveguide 141 in a curved line. This embodiment of the present application does not limit this.

It should be noted that, when the positional relationship between the cantilever 143 and the two coupled microrings 12 is the positional relationship shown in FIG. 10, the displacement adjustment component 142 can control the gap between the cantilever 143 between the adjacent microrings 12 Move inside.

In summary, the optical add-drop multiplexer provided by the embodiments of the present application can adjust the coupling coefficient between every two coupled waveguides in the filter unit through the adjustment of the TC and the MEMS coupler, In order to adjust the filtering spectrum of the filtering unit, the optical add / drop multiplexer can download / upload optical signals of different types of filtering spectrum. Using the optical add-drop multiplexer of the present application, it is possible to download / upload optical signals of different types of filter spectra without configuring multiple optical add-drop multiplexers in each transmission node, which effectively reduces optical communication The complexity of the network, and reduces the difficulty of operation and maintenance of the optical add-drop multiplexer configured in the transmission node.

In practical applications, the optical signal has two modes of polarization components, namely TE mode polarization component and TM mode polarization component. Because the polarized component of the TE mode and the polarized component of the TM mode have large differences in effective refractive index difference and group refractive index, etc., usually one waveguide transmits one polarization mode optical signal. In order to enable the waveguide in the optical add-drop multiplexer in the above embodiment to transmit a polarization mode optical signal, the optical add-drop multiplexer in the embodiment of the present application may also include some other structures. The following embodiments of the present application The two implementations are used as examples to illustrate schematically:

In the first implementation, the schematic structural diagram of the optical add-drop multiplexer is shown in FIG. 11. The optical add-drop multiplexer may further include: an input-output pre-processing unit 30 and a plurality of merge separation units 40. The merging and separating units 40 correspond to the cascaded filtering units in one-to-one correspondence. That is to say, one filtering unit is configured with one merge separation unit. The pre-processing unit input-output port and a first lightwave transmission input port of the first filter unit is connected to i 10 ₁ 30, input and output through port t pre-processing unit and the second light wave transmission port 30 of the last filter unit 10 _n is Connection; the two light wave transmission ports in each merge separation unit 40 are respectively connected to the upload port a and download port d of the corresponding filter unit.

In the embodiment of the present application, the multiple cascaded filter units and the multiple junction / separation units 40 are used for uploading and downloading optical signals of multiple channels. Among them, one filter unit and its corresponding merge and separation unit 40 are used to realize the upload and download of optical signals of one channel. In each channel:

When the channel is in the optical signal download state, FIG. 12 shows the optical path diagram when the channel in the optical add / drop multiplexer shown in FIG. 11 is in the optical signal download state. The input-output pre-processing unit 30 is used to process the input optical signal into Q _TE and P _TE and transmit it to multiple cascaded filtering units. Q _TE represents the optical signal in the transverse electric field TE mode, and P _TE represents the optical signal in the transverse magnetic field TM mode is rotated into the optical signal in the TE mode. Illustratively, Q _TE is transmitted to the first filter unit ₁₀₁ in the input port i, P _TE is transmitted to the port through a filter unit 10, the last t _n-in.

The filtering unit is used to transmit the first Q _TE of the specified wavelength in the Q _TE and the first P _TE of the specified wavelength in the P _TE to the corresponding merge separation unit 40. In the embodiment of the present application, the download port d of the filter unit can output an optical signal that satisfies the resonance condition of the micro ring 12 in Q _TE . That is, the first Q _{TE of the} specified wavelength can be output; the upload port a of the filter unit can output the optical signal that satisfies the resonance condition of the microring 12 in the P _TE , that is, the first P _{TE of the} specified wavelength can be output. The first Q _TE output from the download port d of the filter unit and the first P _TE output from the upload port a can be transmitted to the merge separation unit 40 corresponding to the filter unit.

The merging and separating unit 40 is used for merging the received first Q _TE and first P _TE and outputting the result. In the embodiment of the present application, after the merging and separating unit 40 receives the first Q _TE and the first P _TE , the two signals are merged and output.

FIG. 13 shows an optical path diagram when the channels in the optical add / drop multiplexer shown in FIG. 11 are in the optical signal uploading state. The merging and separating unit 40 is used to process the input optical signal into a second Q _TE and a second P _TE , and transmit the second Q _TE and the second P _TE to the input and output pre-processing unit 30 through corresponding channels. Illustratively, the merge separation unit 40 can transmit the second Q _TE through the download port d of the filter unit to the input-output pre-processing unit 30, and the merge separation unit 40 can transmit the second P _TE through the upload port a of the filter unit to Input output pre-processing unit 30.

In the present application embodiment, the input and output pre-processing unit 30 is further configured to, after receiving from the Q _TE and P _TE output from a plurality of cascaded filtering unit, and the received Q _TE and P _TE output for merging process. Illustratively, the input and output pre-processing unit capable of receiving an input port 30 i is output from the first filtering unit ₁₀₁ is P _TE, and received from the last filter unit P _TE pass-through output port 10 _n of t, the received Q _TE and P _TE are combined and output.

Specifically, as shown in FIG. 11, each merge separation unit 40 includes: a first PSR 41, a second PSR 42, a first input-output separator 43 and a second input-output separator 44. In each merge separation unit 40:

The input port of the first input-output splitter 43 is connected to the upload port a of the corresponding filter unit, the output port of the first input-output splitter 43 is connected to the optical wave splitting port of the first PSR 41, and the first input-output splitter 43 The light wave transmission port is connected to the light wave beam splitting rotation port of the second PSR 42.

The input port of the second input-output splitter 44 is connected to the download port d of the corresponding filter unit, the output port of the second input-output splitter 44 is connected to the optical beam splitting rotation port of the first PSR 41, and the second input-output splitter The light wave transmission port of 44 is connected to the light beam splitting port of the second PSR 42.

In the embodiment of the present application, the first input-output splitter 43 is used to receive the first P _TE and transmit the first P _TE to the optical beam splitting rotation port of the second PSR 42. The second input-output splitter 44 is used to receive the first Q _TE and transmit the first Q _TE to the optical beam splitting port of the second PSR 42, and the second PSR 42 is used to convert the first P _TE to the first P _TM , The first P _TM and the first Q _{TE are} merged, and the merged first P _TM and the first Q _TE are output through the optical wave transmission port of the second PSR 42, so that the optical signal can be downloaded.

The first PSR 41 is used to process the input optical signal into a second Q _TE and a second P _TE , and transmit the second Q _TE to the output of the first input-output splitter 43 through the optical wave splitting port of the first PSR 41 Port, the second P _TE is transmitted to the output port of the second input-output splitter 44 through the optical beam splitting rotation port in the first PSR 41, and the second Q _TE and the second P _TE are transmitted to the input and output pre-processing through the corresponding channels Unit 30, so that the optical signal can be uploaded.

Specifically, as shown in FIG. 11, the input-output preprocessing unit 30 includes: a third input-output separator 31, a fourth input-output separator 32, a third PSR 33, and a fourth PSR 34.

Third input-output splitter input port and a first filter unit 31 i 10 ₁ input port is connected to a third input output port of the fourth splitter output light wave 34 of the PSR 31 is connected to beam port, a third input-output The optical wave transmission port of the splitter 31 is connected to the optical wave splitting rotation port of the third PSR 33.

The input port i of the fourth input-output splitter 32 is connected to the through port t of the last filter unit 10 _n , the output port of the fourth input-output splitter 32 is connected to the optical beam splitting rotation port of the fourth PSR 34, the fourth input The optical wave transmission port of the output splitter 32 is connected to the optical wave splitting port of the third PSR 33.

In the embodiment of the present application, the fourth PSR 34 is used to process the optical signal input from its optical wave transmission port into Q _TE and P _TE , and transmit Q _TE to the first filter unit through the third input-output splitter 31 The input port i of 10 ₁ transmits P _TE through the fourth input-output splitter 32 to the through port t of the last filter unit 10 _n , so that the optical signal input to the multiple cascaded filter units is only one TE The optical signal of the polarization component of the mode.

The third PSR 33 is used to receive P _TE from the output of the third input-output splitter 31, and to receive Q _TE output from the optical wave transmission port of the fourth input-output splitter, convert P _TE to P _TM , and convert P _TM Converge with Q _TE , and output the combined P _TM and Q _TE through the optical transmission port of the third PSR 33, so that only one TE mode polarized component optical signal output from multiple cascaded filter units is converted It is an optical signal with two polarization modes.

In the second implementation, the schematic structural diagram of the optical add-drop multiplexer is shown in FIG. 14. The optical add-drop multiplexer includes, in addition to the set of multiple cascaded filter units in FIG. 3, another set of multiple cascaded filter units, an input-output preprocessing unit 30, and multiple separation units 50和 多 合 联合 单元 60。 And a number of confluence unit 60. At this time, the optical add-drop multiplexer includes two sets of multiple cascaded filter units. A plurality of separating units 50, a plurality of merging units 60, and a group of a plurality of cascaded filter units correspond to another group of a plurality of cascaded filter units. That is to say, the two filtering units are configured with a separating unit and a merging unit, and the two filtering units respectively belong to two sets of multiple cascaded filtering units.

A first input-output lightwave transmission pre-processing unit with a set of first ports are a plurality of cascaded filter units in the filter unit input port i 10 _1, and another set of filter unit 30, a plurality of cascaded The input port i of the first filter unit 10 ₁₁ is connected; the second light wave transmission port of the input and output pre-processing unit 30 is respectively connected to the through port t in the last filter unit 10 _n of a group of multiple cascaded filter units, And the through port t in the last filter unit 10 _nn of another set of multiple cascaded filter units is connected. Illustratively, the input-output pre-processing unit 30 may include: a first PBS 35 and a second PBS 36, which are respectively connected to the input port i of the first filter unit among the two sets of multiple cascaded filter units The second PBS 36 is respectively connected to the through port t of the last filter unit in the two sets of multiple cascaded filter units.

The light wave transmission port of each merging unit 60 is respectively connected with the download port d of the corresponding filter unit in a group of multiple cascaded filter units, and the corresponding filter unit download port d in another group of multiple cascaded filter units connection. Exemplarily, each merging unit 60 is a third PBS, and the third PBS is respectively connected to the download ports d of the corresponding two filtering units.

The light wave transmission port of each separation unit 50 is respectively connected to the upload port a of the corresponding filter unit in a group of multiple cascaded filter units, and the upload port a of the corresponding filter unit in another group of multiple cascaded filter units connection. Exemplarily, each separation unit 50 is a fourth PBS, and the fourth PBS is respectively connected to the upload ports a of the corresponding two filter units.

In the embodiment of the present application, two sets of multiple cascaded filter units, multiple separation units 50, and multiple merge units 60 are used to implement upload and download of multiple channels of optical signals. Among them, one separating unit 50, one merging unit 60, and two corresponding filtering units in two sets of multiple cascaded filtering units are used to realize uploading and downloading of optical signals of one channel.

In each channel:

FIG. 15 shows an optical path diagram when the channels in the optical add / drop multiplexer shown in FIG. 14 are in the optical signal download state. The input-output pre-processing unit 30 is used to process the input optical signals into Q _TE and P _TM , and transmit them to two sets of multiple cascaded filtering units respectively. Illustratively, the input optical signal may be processed into Q _TE and P _TM through the first PBS 35 and transmitted to two sets of multiple cascaded filter units respectively.

The first filtering unit is used to transmit the third Q _TE of the specified wavelength in the Q _TE to the corresponding merging unit 60. The first filtering unit is a filtering unit in a group of multiple cascaded filtering units.

The second filtering unit is used to transmit the third P _TM of the specified wavelength in the P _TM to the corresponding merging unit 60. The second filtering unit is a filtering unit corresponding to the first filtering unit in another group of multiple cascaded filtering units.

The merging unit 60 is configured to output the third Q _TE and the third P _TM after the merging process. For example, the received third Q _TE and the third P _TM may be combined and output through the third PBS 61.

FIG. 16 shows an optical path diagram when the channels in the optical add / drop multiplexer shown in FIG. 14 are in the optical signal uploading state. The separating unit 50 is used to process the input optical signal into the fourth Q _TE and the fourth P _TM , and transmit the fourth Q _TE and the fourth P _TM to the input and output pre-processing unit 30 through the corresponding channels. Illustratively, the input optical signal may be processed into the fourth Q _TE and the fourth P _TM through the fourth PBS 51.

In the embodiment of the present application, the input-output pre-processing unit 30 is further used to receive Q _TE and P _TM respectively output from two sets of multiple cascaded filtering units, and combine the two to output. For example, the Q _TE and P _TM respectively output from the two sets of multiple cascaded filter units may be received through the second PBS 36, and the received Q _TE and P _{TM may be} combined and output.

An embodiment of the present application provides an optical signal processing method, which is applied to the optical add-drop multiplexer shown in FIG. 3, FIG. 11, or FIG. The optical signal processing method includes: adjusting the TC and the MEMS coupler in each filter unit to adjust the filter spectrum of the filter unit to the target filter spectrum.

In the embodiments of the present application, there are various implementation manners for adjusting the current filtering spectrum of the filtering unit to the target filtering spectrum, and the following embodiments will take two implementations as examples for schematic description.

In the first implementation, if the difference between the current filter spectrum type of the filter unit and the target filter spectrum type is small, the foregoing optical signal processing method may include: when the filter unit is in an optical signal uploading state or an optical signal downloading state At this time, adjust the TC and MEMS coupler to adjust the filter spectrum of the filter unit to the target filter spectrum.

If the difference between the current filter spectrum type of the filter unit and the target filter spectrum type is small, it will not affect the filter performance of other filter units during the adjustment process. In this case, the filter unit is in the state of optical signal upload or When the optical signal is downloaded, the TC and MEMS coupler in the filter unit are directly controlled to adjust the filter spectrum of the filter unit to the target filter spectrum.

In the second implementation manner, if the difference between the current filtering spectrum of the filtering unit and the target filtering spectrum is large, the above-mentioned optical signal processing method may include:

Step A1: controlling the TC provided between the first port waveguide and the coupled microring, so that all optical signals input from the input port of the first port waveguide are transmitted to the through port of the first port waveguide.

Step B1: controlling the TC provided between the second port waveguide and the coupled microring to adjust the coupling coefficient between the second waveguide and the coupled microring, and controlling each MEMS coupler to adjust two adjacent ones of the multiple microrings The coupling coefficient between the micro rings.

Step C1: Control the TC provided between the first port waveguide and the coupled micro-ring to adjust the coupling coefficient between the first waveguide and the coupled micro-ring, so that the filtering spectrum of the filtering unit is adjusted to the target filtering spectrum.

If the current filter spectrum type of the filter unit is significantly different from the target filter spectrum type, the filter performance of other filter units may be affected during the adjustment process. At this time, the above steps A1 to C1 effectively prevent the filtering unit from affecting the filtering performance of other filtering units during the process of adjusting the filtering spectrum.

It should be noted that, for the principle of the foregoing optical signal processing method, reference may be made to the foregoing embodiment for describing the structure of the optical add-drop multiplexer, and details are not described herein again.

The embodiment of the present application provides another optical signal processing method, which is applied to the optical add-drop multiplexer shown in FIG. 11.

When the channel is in the optical signal download state, the optical signal processing method may further include:

Step A2: The fourth PSR processes the input optical signal into Q _TE and P _TE .

Step B2: The fourth PSR transmits Q _TE to the input port of the first filtering unit through the third input-output splitter, and transmits P _TE to the through port of the last filtering unit through the fourth input-output splitter.

Step C2: The first input-output splitter receives the first P _TE and transmits the first P _TE to the second PSR.

Step D2: The second input-output splitter receives the first Q _TE and transmits the first Q _TE to the second PSR.

Step E2: PSR second first P _TE into a first P _TM, a first P _TM merging with the first Q _TE, the first P _TM and the first Q _TE and outputs the confluence.

When the channel is in the optical signal uploading state, the optical signal transmission method may further include:

Step A3: The first PSR processes the input optical signal into a second Q _TE and a second P _TE .

Step B3: The first PSR transmits the second Q _TE to the first input-output separator to the input-output pre-processing unit.

Step C3: The first PSR transmits the second P _TE to the second input-output separator to the input-output pre-processing unit.

In practical applications, the optical signal transmission method may further include:

Step A4: The third PSR receives Q _TE output from the third input-output splitter, and receives P _TE output from the fourth input-output splitter.

Step B4: The third PSR converts P _TE to P _TM , merges P _TM and Q _TE , and outputs the combined P _TM and Q _TE .

It should be noted that, for the principle of the foregoing optical signal processing method, reference may be made to the foregoing embodiment described for the structure of the optical add / drop multiplexer shown in FIG. 11, and details are not described herein again.

The embodiment of the present application provides yet another optical signal processing method, which is applied to the optical add-drop multiplexer shown in FIG. 14.

When the channel is in the optical signal download state, the optical signal transmission method may further include:

Step A5: The first PBS processes the input optical signal into Q _TE and P _TM .

Step B5: The first PBS transmits Q _TE to the input port of the first filter unit in a group of multiple cascaded filter units.

Step C5: The first PBS transmits the P _TM to the input port of the first filter unit in another set of multiple cascaded filter units.

Step D5: receiving a third third PBS and a third P _TM Q _TE, the third and the third P _TM confluence Q _TE, the third and the third P _TM outputs Q _TE confluent.

When the channel is in the optical signal uploading state, the optical signal transmission method may further include:

Step A6: The fourth PBS processes the input optical signal into the fourth Q _TE and the fourth P _TM ;

Step B6: The fourth PBS transmits the fourth Q _TE to the input-output pre-processing unit through the upload port of the first filtering unit.

Step C6: The fourth PBS transmits the fourth P _TM to the input-output pre-processing unit through the upload port of the second filtering unit.

In practical applications, the optical signal processing method may further include:

Step A7: The second PBS receives Q _TE and P _TM output from two sets of multiple cascaded filter units, respectively.

Step B7: The second PBS merges the received P _TM and Q _TE , and outputs the merged P _TM and Q _TE .

It should be noted that, for the principle of the foregoing optical signal processing method, reference may be made to the foregoing embodiment described for the structure of the optical add / drop multiplexer shown in FIG. 14, and details are not described herein again.

An embodiment of the present application further provides a chip including the optical add-drop multiplexer in the above embodiment. For example, the chip includes: the optical add / drop multiplexer shown in FIG. 3, FIG. 11 or FIG. The chip may further include: a control circuit, which is used to implement the optical signal processing method in the embodiments of the present application.

The above are only preferred embodiments of this application and are not intended to limit this application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application should be included in the protection of this application Within range.

Claims (17)

1. An optical add-drop multiplexer is characterized by comprising: a plurality of cascaded filter units, wherein:

   Each of the filtering units includes: two port waveguides, and a plurality of microrings located between the two port waveguides;

   Each of the port waveguides is coupled to one of the plurality of microrings, and a tunable coupler (TC) is provided between each of the port waveguides and the coupled microrings. The TC is used to adjust the coupling coefficient between the port waveguide and the coupled microring;

   Each of the filtering units further includes: at least one microelectromechanical system MEMS coupler, and each of the MEMS couplers is used to adjust a coupling coefficient between two adjacent microrings in the plurality of microrings;

   Any two adjacent filter units are connected by a port waveguide;

   The TC and MEMS couplers in each filter unit are used to adjust the filter spectrum of the filter unit to the target filter spectrum.
2. The optical add / drop multiplexer according to claim 1, wherein the two port waveguides include: a first port waveguide having an input port and a through port, and a port download port and an upload port Second port waveguide;

   The TC in each of the filter units is also used to control all optical signals input from the input port of the first port waveguide to be transmitted to the through port of the first port waveguide.
3. The optical add / drop multiplexer according to claim 1 or 2, wherein every two adjacent microrings in the plurality of microrings are coupled through a coupling waveguide in each microring;

   Each of the MEMS couplers includes: a coupling waveguide in each of the two coupled microrings, and a displacement adjustment component;

   At least one of the coupling waveguides of the two coupled microrings is a suspended waveguide;

   The displacement adjustment component is used to control the movement of the suspended waveguide to adjust the coupling coefficient between the two coupled microrings.
4. The optical add / drop multiplexer according to claim 3, wherein the plurality of microrings are composed of deep waveguides or shallow waveguides.
5. The optical add / drop multiplexer according to claim 1 or 2, wherein every two adjacent microrings in the plurality of microrings are coupled through a coupling waveguide in each microring;

   Each of the MEMS couplers includes: a coupling waveguide, a cantilever, and a displacement adjustment component in each of the two coupled microrings;

   An orthographic projection of the cantilever on the two coupled microrings, there is an overlapping area with each coupling waveguide in the two coupled microrings; or, the cantilever is on the two coupled The orthographic projection on the microring is between the two coupled microrings;

   The refractive index of the cantilever is greater than the refractive index of the filler between the two coupled microrings;

   The displacement adjustment component is used to control the cantilever to move toward or away from the coupling waveguide to adjust the coupling coefficient between the two coupled microrings.
6. The optical add-drop multiplexer according to any one of claims 2 to 5, wherein the optical add-drop multiplexer further comprises: an input-output preprocessing unit and a plurality of merge separation units, the plurality of merges One-to-one correspondence between the separation unit and the multiple cascaded filter units;

   The first light wave transmission port of the input-output pre-processing unit is connected to the input port of the first filter unit, and the second light wave transmission port of the input-output pre-processing unit is connected to the through port of the last filter unit;

   The two light wave transmission ports of each merge separation unit are respectively connected to the upload port and download port of the corresponding filter unit.
7. The optical add / drop multiplexer according to claim 6, wherein each of the combining and separating units comprises: a first polarization beam splitter rotator PSR, a second PSR, a first input-output splitter and a second input Output splitter

   The first input-output splitter and the second input-output splitter each have an input end, an output end, and an optical wave transmission port, and both the first PSR and the second PSR have an optical wave transmission port, an optical wave splitting port, and an optical wave Beam rotation port;

   For each of the merge separation units:

   The input port of the first input-output splitter is connected to the upload port of the corresponding filter unit, the output port of the first input-output splitter is connected to the optical beam splitting port of the first PSR, and the first input The optical wave transmission port of the output splitter is connected to the optical wave beam splitting rotation port of the second PSR,

   The input port of the second input-output splitter is connected to the download port of the corresponding filter unit, and the output port of the second input-output splitter is connected to the optical beam splitting rotation port of the first PSR, the second The optical wave transmission port of the input-output splitter is connected to the optical wave beam splitting port of the second PSR.
8. The optical add / drop multiplexer according to claim 6, wherein the input-output pre-processing unit includes: a third input-output splitter, a fourth input-output splitter, a third PSR, and a fourth PSR;

   The third input-output splitter and the fourth input-output splitter each have an input end, an output end, and an optical wave transmission end, and the third PSR and the fourth PSR each have an optical wave transmission port and an optical wave splitting port The rotating end of the beam splitter;

   The input port of the third input-output splitter is connected to the input port of the first filtering unit, and the output port of the third input-output splitter is connected to the optical wave splitting port of the fourth PSR, the The optical wave transmission port of the third input-output splitter is connected to the optical wave beam splitting rotation port of the third PSR,

   The input port of the fourth input-output splitter is connected to the through port of the last filter unit, and the output port of the fourth input-output splitter is connected to the optical beam splitting rotation port of the fourth PSR, the The optical wave transmission port of the fourth input-output splitter is connected to the optical wave splitting port of the third PSR.
9. The optical add / drop multiplexer according to any one of claims 6 to 8, wherein the multiple cascaded filter units and the multiple junction / separation units are used to implement optical signal uploading of multiple channels and Download, in each said channel:

   When the channel is in the optical signal downloading state, the input-output preprocessing unit is used to process the input optical signal into Q _TE and P _TE , and transmit the processed Q _TE and P _TE to the multiple Cascaded filter unit, Q _TE represents the optical signal in the transverse electric field TE mode, and P _TE represents the optical signal in the transverse magnetic field TM mode is rotated into the optical signal in the TE mode;

   The filtering unit is used to transmit the first Q _TE of the specified wavelength in the Q _TE and the first P _TE of the specified wavelength in the P _TE to the corresponding merge separation unit;

   The merging and separating unit is configured to perform merge processing on the received first Q _TE and the first P _TE, and then output it;

   When the channel is in an optical signal uploading state, the converging and separating unit is used to process the input optical signal into a second Q _TE and a second P _TE , and the second Q _TE and the second P _TE It is transmitted to the input-output preprocessing unit through the corresponding channel.
10. The optical add / drop multiplexer according to any one of claims 2 to 5, wherein the optical add / drop multiplexer further comprises: another group of multiple cascaded filter units, an input / output preprocessing unit, Multiple separation units and multiple merge units, the multiple separation units, the multiple merge units, a group of multiple cascaded filter units and another group of multiple cascaded filter units correspond one-to-one;

    The first light wave transmission port of the input-output preprocessing unit is respectively connected to the input port of the first filter unit in a group of multiple cascaded filter units, and the first port in another group of multiple cascaded filter units The input ports of each filter unit are connected,

    The second light wave transmission port of the input-output preprocessing unit is respectively connected to the through port of the last filter unit in a group of multiple cascaded filter units, and the last filter in another group of multiple cascaded filter units Unit through port connection;

    The light wave transmission port of each of the merging units is respectively connected to the download port of the corresponding filter unit in a group of multiple cascaded filter units, and the download port of the corresponding filter unit in another group of multiple cascaded filter units ;

    The light wave transmission port of each separation unit is respectively connected to the upload port of the corresponding filter unit in a group of multiple cascaded filter units, and the upload port of the corresponding filter unit in another group of multiple cascaded filter units .
11. The optical add / drop multiplexer according to claim 10, wherein the input-output preprocessing unit includes: a first optical wave splitter PBS and a second PBS;

    Both the first PBS and the second PBS have an optical wave transmission port, a first optical wave beam splitting port, and a second optical wave beam splitting port;

    The first optical wave splitting port of the first PBS is connected to the input port of the first filtering unit in the set of multiple cascaded filtering units, and the second optical wave splitting port of the first PBS is The input port of the first filter unit in another set of multiple cascaded filter units is connected,

    The first optical wave splitting port of the second PBS is connected to the through port in the last filtering unit of the plurality of cascaded filtering units, and the second optical wave splitting port of the second PBS is connected to all The through port connection in the last filter unit of the other set of multiple cascaded filter units is described.
12. The optical add / drop multiplexer according to claim 10, wherein each of the merging units includes a third PBS, and each of the separating units includes a fourth PBS;

    Each of the third PBS and the fourth PBS has an optical wave transmission port, a first optical wave beam splitting port, and a second optical wave beam splitting port;

    The first light wave beam splitting port of the third PBS is connected to the download port of the corresponding filter unit in a group of multiple cascaded filter units, and the second light wave beam splitting port of the third PBS is connected to another group of multiple The download port of the corresponding filter unit in the cascaded filter unit is connected;

    The first optical wave splitting port of the fourth PBS is connected to the upload port of the corresponding filtering unit in a group of multiple cascaded filtering units, and the second optical wave splitting port of the fourth PBS is connected to another group of multiple The upload port of the corresponding filter unit in the cascaded filter unit is connected.
13. The optical add-drop multiplexer according to any one of claims 10 to 12, wherein two sets of multiple cascaded filter units, the multiple separation units, and the multiple merge units are used to implement multiple Optical signal upload and download of channels, in each of the channels:

    When the channel is in the optical signal download state, the input-output preprocessing unit is used to process the input optical signal into Q _TE and P _TM , and transmit the processed Q _TE and P _TM to the two respectively A group of multiple cascaded filter units, where Q _TE represents the optical signal in TE mode and P _TM represents the optical signal in TM mode;

    A first filtering unit for the specified wavelength in the Q _TE third confluence unit Q _TE corresponding to the transmission;

    Confluent second filtering unit for transmission of the cell of the third P _TM P _TM specified wavelengths corresponding to;

    The corresponding merging unit is used to merge the received third Q _TE and the third P _TM and output;

    When the channel is in an optical signal uploading state, the separation unit is used to process the input optical signal into a fourth Q _TE and a fourth P _TM , and pass the fourth Q _TE and the fourth P _TM through The channel is transmitted to the input and output preprocessing unit;

    Wherein, the first filtering unit is one filtering unit in the group of multiple cascaded filtering units, and the second filtering unit is the first filtering unit in the other group of multiple filtering units Corresponding filter unit.
14. The optical add / drop multiplexer of claim 1, wherein each of the TCs includes: a first sub-waveguide in the port waveguide and a second in the micro-ring coupled to the port waveguide A sub-waveguide, and a first phase controller PS provided on the first sub-waveguide, the first PS is used to adjust the optical signal transmitted in the first sub-waveguide and the second sub-waveguide The phase difference between optical signals.
15. The optical add / drop multiplexer according to claim 1, wherein each micro ring is further provided with a second PS, and the second PS is used to adjust the resonance wavelength of the micro ring, wherein, In each of the filtering units, the second PS, the TC, and the MEMS coupler do not have overlapping areas.
16. An optical signal processing method, characterized in that the method is applied to the optical add / drop multiplexer according to any one of claims 1 to 15, and the method includes:

    Adjusting the TC and MEMS coupler in each of the filtering units to adjust the filtering spectrum of the filtering unit to the target filtering spectrum.
17. The method according to claim 16, wherein the two port waveguides include: a first port waveguide having an input port and a through port, and a second port waveguide having a download port and an upload port;

    The adjusting the TC and MEMS couplers in each of the filtering units to adjust the filtering spectrum of the filtering unit to the target filtering spectrum includes:

    Controlling the TC provided between the first port waveguide and the coupled microring, so that all optical signals input from the input port of the first port waveguide are transmitted to the through port of the first port waveguide;

    Controlling the TC provided between the second port waveguide and the coupled micro ring to adjust the coupling coefficient between the second waveguide and the coupled micro ring, and controlling each of the MEMS couplers to adjust the Coupling coefficient between two adjacent microrings in multiple microrings;

    Controlling the TC provided between the first port waveguide and the coupled micro ring to adjust the coupling coefficient between the first waveguide and the coupled micro ring, so that the filtering spectrum of the filtering unit is adjusted to Target filter spectrum.

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