CN113985531B - Wavelength selection switch and temperature drift compensation method thereof - Google Patents
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- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
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- G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
- G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
- G02B6/29304—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means operating by diffraction, e.g. grating
- G02B6/29305—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means operating by diffraction, e.g. grating as bulk element, i.e. free space arrangement external to a light guide
- G02B6/29313—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means operating by diffraction, e.g. grating as bulk element, i.e. free space arrangement external to a light guide characterised by means for controlling the position or direction of light incident to or leaving the diffractive element, e.g. for varying the wavelength response
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- G02B6/29379—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means characterised by the function or use of the complete device
- G02B6/2938—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means characterised by the function or use of the complete device for multiplexing or demultiplexing, i.e. combining or separating wavelengths, e.g. 1xN, NxM
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Abstract
The invention provides a wavelength selection switch and a temperature drift compensation method thereof. The reference light and the signal light provided by the illumination unit enter the optical conversion unit through the input and output unit to form reference diffraction light and signal diffraction light to be transmitted to the control unit. The phase of each pixel corresponding to the reference diffraction light distribution on the control unit is adjusted, and the phase grating pattern parameters of the reference diffraction light can be changed to compensate the insertion loss of the reference diffraction light. And according to the correction quantity of the phase grating pattern parameter after the reference light insertion loss compensation, the phase shift quantity of each signal diffraction light is obtained so as to compensate the insertion loss of each signal diffraction light. Therefore, in the invention, the reference light and the signal light pass through the internal optical element of the wavelength selective switch, and the insertion loss of each signal diffraction light is compensated by taking the insertion loss of the compensated reference diffraction light as a reference, so that the compensation precision is high, the constant temperature state is not needed, the power consumption is reduced, the working stability is improved, the preparation cost is reduced, and the volume of the device is reduced.
Description
Technical Field
The invention relates to the technical field of optical communication, in particular to a wavelength selection switch and a temperature drift compensation method thereof.
Background
Wavelength Division Multiplexing (WDM) is the most common optical layer networking technology at present, and by Multiplexing different wavelengths in one optical fiber for transmission, it is easy to realize the transmission capacity in gigabits per second (Gbit/s) or even ethernet bits per second (Tbit/s) as the transmission unit. As core Optical switching devices in a WDM network, Optical cross-connectors (OXCs) and Reconfigurable Optical Add-Drop multiplexers (ROADMs) can configure any wavelength at any port.
A Wavelength Selective Switch (WSS) is a core device used to implement OXC and ROADM, and has a function of outputting an input Wavelength from an arbitrary output port. The wavelength selective switch mainly includes Liquid Crystal On Silicon (LCOS), Micro Electro-Mechanical Systems (MEMS), and Liquid Crystal technology (Li quick Crystal, LC). The wavelength selection switch based on LCOS technology has the working principle that light beams with different wavelengths are subjected to spectrum expansion by utilizing diffraction gratings to different areas of the surface of the LCOS, the transmission direction of the light beams is controlled by modulating a phase diffraction grating formed by the LCOS, and the light beams with fixed wavelengths are output to a specified communication port, so that the function of selecting the l multiplied by N wavelengths is realized. The working principle of the wavelength selective switch based on the MEMS technology is as follows: the light beams with different wavelengths are subjected to spectrum spreading by the diffraction grating to the micro-mirrors in different areas of the MEMS, and the light with any wavelength can be transmitted to a specified output port without crosstalk by rotating the micro-mirrors, so that the function of selecting the l multiplied by N wavelength is realized. The wavelength selective switch based on the MEMS technology has low insertion loss (abbreviated as "insertion loss"), but cannot be adapted to flexible application of communication channel bandwidth. The working principle of the wavelength selective switch based on the LC technology is as follows: the beam direction is changed by the superposition of N (2N = N) single liquid crystals, and the 1 XN wavelength selection function is realized. The wavelength selective switch based on the LC technology requires a large number of stacked single liquid crystals (N, 2N = N) when implementing a 1 × N wavelength selective function, and each output port of the wavelength selective switch needs to be individually adjusted due to manufacturing errors of the single liquid crystals therein. Therefore, the process is difficult to implement, and the expansion of the output port is difficult. Compared with the LC technology and the MEMS technology, the wavelength selective switch based on the LCOS technology has the characteristic of flexibly adapting to the communication bandwidth, and becomes the mainstream of the WSS technology.
The optical network is divided into a wide area network, a metropolitan area network and an access network, wherein the wide area network is of a full-interconnection structure, and nodes are connected by adopting OXC; the metropolitan area network and the access network are bidirectional optical fiber ring network structures, and ROADM is adopted for multiplexing/demultiplexing. The wavelength selective switches are usually distributed in a machine room at a plurality of different nodes of the optical network, and the temperature of the machine room changes with the temperature change of the environment, so the wavelength selective switches need to be capable of stably and reliably operating in a large temperature range. The optical elements in the wavelength selective switch are generally glass elements, and these optical elements change with the change of the ambient temperature. For example, the optical element expands with heat and contracts with cold due to high or low temperature, and the optical characteristics thereof change, or the optical element and the optical substrate are bonded with an adhesive, and the relative position of the optical device is affected by deformation of the optical substrate due to change in environmental temperature. In addition, the change of the grating temperature can cause the number of grating lines to change, thereby causing the angle of the emergent light beam to change. Therefore, the light beams with various wavelengths deviate from the original positions of the emergent ports due to the influence of the ambient temperature, so that the stability of the insertion loss of the wavelength selective switch is influenced, and the wavelength selective switch cannot work normally due to too large insertion loss change.
At present, in order to keep the temperature of the wavelength selective switch constant, a semiconductor refrigerator (TEC) is generally used, or a heating plate is used to make the temperature of the wavelength selective switch within a certain range, then a temperature sensor is used to measure the temperature, and a LCOS pattern is corrected by measured real-time temperature data, so as to compensate for the change of insertion loss and improve the stability of the wavelength selective switch.
However, the temperature control method in the prior art greatly increases the power consumption of the wavelength selective switch, and the compensation insertion loss method for performing LCOS pattern correction by measuring the temperature of the wavelength selective switch in real time cannot compensate the problems of uneven temperature distribution or poor repeatability inside the wavelength selective switch, so that the finally obtained compensation is not accurate.
Therefore, a new method for compensating the temperature drift of the wavelength selective switch is needed to reduce the power consumption of the wavelength selective switch, improve the compensation accuracy, and further ensure the stability of the wavelength selective switch.
Disclosure of Invention
The invention aims to provide a wavelength selective switch and a temperature drift compensation method thereof, so as to solve the problem of unstable work caused by the influence of temperature on the wavelength selective switch.
To solve the above technical problem, the present invention provides a wavelength selective switch, including: the device comprises an illumination unit, an input and output unit, an optical conversion unit, a control unit with an LCOS panel and a detection unit;
the illumination unit is used for providing reference light and signal light;
the input and output unit comprises a reference input port, a reference output port, a signal input port and a plurality of signal output ports, the reference light enters the optical conversion unit through the reference input port, and the signal light enters the optical conversion unit through the signal input port;
the optical conversion unit is used for dispersing the reference light and the signal light, separating the reference light and the signal light into various paths of signal diffraction light and reference diffraction light with different wavelengths, and distributing the signal diffraction light and the reference diffraction light to different areas of the LCOS panel according to a wavelength sequence;
the LCOS panel is used for reflecting the reference diffraction light and each path of signal diffraction light to the optical conversion unit, and then outputting the reference diffraction light and each path of signal diffraction light through the reference output port and the corresponding signal output port respectively;
the detection unit is used for monitoring the light energy of the reference diffracted light output by the reference output port;
the LCOS panel is further configured to adjust the phase of each pixel corresponding to the distribution of the reference diffracted light on the LCOS panel according to the detection result of the detection unit, so as to change the phase grating pattern parameter of the reference diffracted light, and further change the diffraction angle of the reference diffracted light, so as to perform insertion loss compensation on the reference light; and, according to the correction amount of the phase grating pattern parameter of the reference diffracted light after the reference light insertion loss compensation, the phase shift amount to be compensated of each path of the signal diffracted light can be obtained, and the LCOS panel is further configured to adjust the phase of each corresponding pixel of the signal diffracted light distribution to be compensated on the LCOS panel, so as to perform insertion loss compensation on each path of the signal diffracted light to be compensated.
Optionally, in the wavelength selective switch, the illumination unit includes a laser, a power detector, and an optical communication interface; wherein, the first and the second end of the pipe are connected with each other,
the laser is used for providing the reference light with stable wavelength to the reference input port; the power detector is used for monitoring the power of the laser; the optical communication interface is used for providing the signal light in optical communication to the signal input port.
Optionally, in the wavelength selective switch, the input/output unit is an optical fiber array, and the reference input port, the reference output port, the signal input port, and the plurality of signal output ports are arranged in an array.
Optionally, in the wavelength selective switch, the optical conversion unit includes: a polarizer, a cylindrical mirror, a lens, and a grating; wherein the content of the first and second substances,
the reference light and the signal light are converted into linearly polarized light through the polarizer, reflected to a lens through the cylindrical reflector, focused by the lens, enter the grating, and are diffracted and separated into various paths of signal diffraction light and reference diffraction light with different wavelengths after passing through the grating;
and the signal diffraction light and the reference diffraction light with different wavelengths sequentially pass through the lens and the cylindrical reflector and are reflected to different areas of the LCOS panel through the cylindrical reflector.
Optionally, in the wavelength selective switch, each path of the signal diffraction light and the reference diffraction light with different wavelengths is reflected by the LCOS panel to the cylindrical mirror, and is reflected by the cylindrical mirror to enter the polarizer, and is output by the reference output port and each signal output port after passing through the polarizer.
Optionally, in the wavelength selective switch, the detection unit includes an energy detector, the reference diffracted light enters the energy detector after being output through the reference output port, and the energy detector detects light energy of the reference diffracted light.
Optionally, in the wavelength selective switch, when it is determined that insertion loss compensation needs to be performed on a certain path of the signal diffracted light, the insertion loss of the signal diffracted light is compensated according to a phase shift amount to be compensated of the signal diffracted light obtained in the path, where a phase shift amount ρ of a pixel corresponding to the signal diffracted light distributed on the LCOS panel satisfies a following formula: ρ = (2 π xy σ)/λ;
wherein x is the pixel width, y is the pixel number, and σ is the correction quantity of the phase grating pattern parameter of the reference diffracted light after the reference light insertion loss compensation; and lambda is the wavelength of the central channel of each path of signal diffraction light distributed on the LCOS panel.
Optionally, in the wavelength selective switch, the wavelength range of the reference light is: 1500nm-1700 nm.
Based on the same inventive concept, the invention also provides a wavelength selective switch temperature drift compensation method, which comprises the following steps:
the illumination unit provides reference light and signal light;
the reference light and the signal light respectively enter the optical conversion unit through the reference input port and the signal input port, are converted into diffracted lights with different wavelengths through the optical conversion unit, are transmitted to the LCOS panel of the control unit, and are distributed on different areas of the LCOS panel according to the wavelength sequence; the diffracted light with different wavelengths is reflected to the optical conversion unit by the LCOS panel, and is output through the reference output port and the corresponding signal output port respectively after passing through the optical conversion unit;
the detection unit detects whether the insertion loss of the reference diffracted light exceeds a preset range;
if so, adjusting the phase of each corresponding pixel of the reference diffraction light distribution on the LCOS panel to change the phase grating pattern parameter of the reference diffraction light, and further changing the diffraction angle of the reference diffraction light to compensate the insertion loss of the reference light to a preset value;
and obtaining a phase shift quantity to be compensated of each path of signal diffraction light according to the correction quantity of the phase grating pattern parameter of the reference diffraction light after the insertion loss compensation of the reference light, and respectively adjusting the phase of each corresponding pixel of the distribution of each path of signal diffraction light to be compensated on the LCOS panel according to the phase shift quantity so as to compensate the insertion loss of each path of signal diffraction light to a preset value.
Optionally, in the wavelength selective switch temperature drift compensation method, when it is determined that insertion loss compensation needs to be performed on a certain path of the signal diffraction light, the insertion loss of the signal diffraction light is compensated according to a phase shift amount to be compensated of the obtained path of the signal diffraction light, where a phase shift amount ρ of a pixel corresponding to light distribution of the signal diffraction light on the LCOS panel satisfies the following formula: ρ = (2 π xy σ)/λ;
wherein x is the pixel width, y is the pixel number, and σ is the correction quantity of the phase grating pattern parameter of the reference diffracted light after the reference light insertion loss compensation; and lambda is the wavelength of the central channel of each path of signal diffraction light distributed on the LCOS panel.
In summary, the present invention provides a temperature drift compensation method for the wavelength selective switch. Wherein the wavelength selective switch comprises: the device comprises an illumination unit, an input and output unit, an optical conversion unit, a control unit with an LCOS panel and a detection unit. The illumination unit is used for providing reference light and signal light. The input and output unit comprises a reference input port, a reference output port, a signal input port and a plurality of signal output ports, the reference light enters the optical conversion unit through the reference input port, and the signal light enters the optical conversion unit through the signal input port. The optical conversion unit is used for dispersing the reference light and the signal light, separating the reference light and the signal light into signal diffraction light and reference diffraction light with different wavelengths, and distributing the signal diffraction light and the reference diffraction light to different areas of the LCOS panel according to the wavelength sequence. The LCOS panel is used for reflecting the reference diffraction light and each path of the signal diffraction light to the optical conversion unit, and then outputting the reference diffraction light and each path of the signal diffraction light through the reference output port and the corresponding signal output port respectively. The detection unit is used for monitoring the light energy of the reference diffracted light output by the reference output port.
The LCOS panel is further configured to adjust the phase of each pixel corresponding to the distribution of the reference diffracted light on the LCOS panel according to the detection result of the detection unit, so as to change the phase grating pattern parameter of the reference diffracted light, and further change the diffraction angle of the reference diffracted light, so as to perform insertion loss compensation on the reference light; and, according to the correction amount of the phase grating pattern parameter of the reference diffracted light after the reference light insertion loss compensation, the phase shift amount to be compensated of each path of the signal diffracted light can be obtained, and the LCOS panel is further configured to adjust the phase of each corresponding pixel of the distribution of each path of the signal diffracted light to be compensated on the LCOS panel, so as to perform insertion loss compensation on each path of the signal diffracted light to be compensated.
Therefore, the wavelength selective switch provided by the invention is provided with the reference light, and the reference light and the signal light pass through the internal optical element of the wavelength selective switch, so that the insertion loss of each signal diffraction light is compensated based on changing the pattern parameter of the reference diffraction light phase grating and realizing the compensation of the insertion loss of the reference diffraction light, the compensation precision is high, and the wavelength selective switch does not need to be controlled to be in a constant temperature state, thereby not only reducing the power consumption and the preparation cost of the wavelength selective switch, but also reducing the volume of a device and improving the working stability.
Drawings
Fig. 1 is a schematic structural diagram of a wavelength selective switch according to an embodiment of the present invention.
Fig. 2 is a schematic structural diagram of an optical conversion unit according to an embodiment of the present invention.
FIG. 3 is a diagram showing the distribution of diffracted light in the control unit according to the embodiment of the present invention.
FIG. 4 is a schematic diagram of a phase grating image according to an embodiment of the present invention.
Detailed Description
To further clarify the objects, advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. It is to be noted that the drawings are in greatly simplified form and are not to scale, but are merely intended to facilitate and clarify the explanation of the embodiments of the present invention. Further, the structures illustrated in the drawings are often part of actual structures. In particular, the drawings are intended to show different emphasis, sometimes in different proportions. It should be further understood that the terms "first," "second," "third," and the like in the description are used for distinguishing between various components, elements, steps, and the like, and are not intended to imply a logical or sequential relationship between various components, elements, steps, or the like, unless otherwise indicated or indicated.
To solve the above technical problem, the present embodiment provides a wavelength selective switch. Referring to fig. 1, the wavelength selective switch includes: an illumination unit 10, an input-output unit 20, an optical conversion unit 30, a control unit 40 having an LCOS panel, and a detection unit 50. Wherein the illumination unit 10 is configured to provide reference light and signal light. The input/output unit 20 includes a reference input port 201, a reference output port 202, a signal input port 211, and a plurality of signal output ports 212, the reference light enters the optical conversion unit 30 through the reference input port 201 and is output through the reference output port 202, and the signal light enters the optical conversion unit 30 through the signal input port 211 and is output through each signal output port 212.
The optical conversion unit 30 is configured to disperse the reference light and the signal light, separate the reference light and the signal light into signal diffracted light and reference diffracted light with different wavelengths, and distribute the signal diffracted light and the reference diffracted light to different areas of the LCOS panel according to a wavelength sequence. The reference diffracted light and each path of the signal diffracted light are reflected to the optical conversion unit 30 by the LCOS panel, and then output through the reference output port 202 and the corresponding signal output port 212, respectively. The detection unit 50 is used for monitoring the light energy of the reference diffracted light output by the reference output port 202.
The LCOS panel is further configured to adjust the phase of each pixel corresponding to the reference diffracted light distributed on the LCOS panel according to the detection result of the detection unit 50, so as to change the phase grating pattern parameter of the reference diffracted light, and further change the diffraction angle of the reference diffracted light, so as to perform insertion loss compensation on the reference light. And, according to the correction amount of the phase grating pattern parameter of the reference diffracted light after the reference light insertion loss compensation, the phase shift amount to be compensated of each path of the signal diffracted light can be obtained, and the LCOS panel is further configured to adjust the phase of each corresponding pixel of the distribution of each path of the signal diffracted light to be compensated on the LCOS panel, so as to perform insertion loss compensation on each path of the signal diffracted light to be compensated.
Therefore, in the wavelength selective switch provided in this embodiment, by providing the reference light, and passing both the reference light and the signal light through the internal optical element of the wavelength selective switch, the insertion loss of each signal diffracted light is compensated based on changing the pattern parameter of the reference diffracted light phase grating to compensate the insertion loss of the reference diffracted light, so that the compensation accuracy is high, and the problem of inaccurate compensation due to uneven internal temperature distribution or poor repeatability of the wavelength selective switch is avoided. In addition, the insertion loss compensation caused by temperature drift can be realized without controlling the wavelength selective switch to be in a constant temperature state, the power consumption and the preparation cost of the wavelength selective switch can be reduced, the size of a device can be reduced, and the working stability is improved.
Specifically, referring to fig. 1, the illumination unit 10 includes a laser 101, a power detector 102, and an optical communication interface 103. Wherein the laser 101 is configured to provide the reference light with stable wavelength to the reference input port 201. The power detector 102 is used to monitor the power of the laser 101 to ensure that the reference light with a stable wavelength is provided. The optical communication interface 103 is configured to provide the signal light in optical communication to the signal input port 211. The wavelength bands of the reference light are close to the L-band and the C-band, so that the first area 401 of the LCOS panel, on which the reference diffracted light is projected, can be determined conveniently. Optionally, the wavelength range of the reference light is: 1500nm-1700 nm. The signal light comprises multiple light waves with multiple wavelengths, the wavelength selection switch is used for separating the wave bands of the light waves and selecting the light waves with specific wavelengths.
The input/output unit 20 is an optical fiber array, and the reference input port 201, the reference output port 202, the signal input port 211, and the plurality of signal output ports 212 are arranged in an array. The reference light and the signal light respectively realize input and output of light waves through the corresponding ports of the input and output unit 20. In this embodiment, only 4 signal output ports 212 (a-d) are shown in fig. 1, and optionally 5, 6, 7, and the like, and the number of the signal output ports 212 may be determined according to the type of the selected wavelength, which is not limited in this embodiment. Further, the reference input port 201 and the signal input port 211 in the illumination unit 10 may be the same input port, or may be two input ports. I.e. the reference light and the signal light may be combined into the same port input or separately input via two ports, respectively.
Referring to fig. 2, the optical conversion unit 30 includes, but is not limited to: a polarizer 301, a cylindrical mirror 302, a lens 303, and a grating 304. After the reference light and the signal light enter the optical conversion unit 30, the reference light and the signal light are converted into linearly polarized light through the polarizer 301. Then, the light path is changed by the cylindrical mirror 302, and the changed light path is reflected to the lens 303, enters the grating 304 after being focused by the lens 303, and is diffracted and separated into the signal diffraction light and the reference diffraction light with different wavelengths after passing through the grating 304. The signal diffracted light and the reference diffracted light with different wavelengths sequentially pass through the lens 303 and the cylindrical mirror 302, and are reflected to the control unit 40 by the cylindrical mirror 302.
The signal light and the reference light are diffracted and dispersed after passing through the grating 304, so as to separate the signal diffraction light and the reference diffraction light with different wavelengths. And then reflected by the cylindrical reflector 302, the signal diffracted light and the reference diffracted light after wavelength separation are distributed to different areas of the LCOS panel 40. Referring to FIG. 3, the diffracted lights with different wavelengths λ are distributed at different positions. Wavelength λ of the reference diffracted lightrClose to the communication band, the reference diffracted light is distributed at the edge of the LCOS panel 40.
With reference to fig. 1 and 2, the reference diffracted light and each of the signal diffracted lights are reflected by the LCOS panel 40 to the cylindrical mirror 302, reflected by the cylindrical mirror 302 to enter the polarizer 301, and output by the reference output port 202 and each of the signal output ports 212 after passing through the polarizer 301. Wherein the reference diffracted light outputted through the reference output port 202 is received by the detecting unit 50. The detection unit 50 includes an energy detector for detecting light energy of the reference diffracted light to determine insertion loss of the reference diffracted light.
Further, the LCOS panel 40 includes a plurality of pixels, each of which can change the refractive index of the liquid crystal by changing the magnitude of the driving electric field above and below the liquid crystal, thereby changing the phase of the light beam passing through the liquid crystal. Therefore, by adjusting the phase of each pixel corresponding to the diffracted light, a predetermined phase raster pattern can be obtained. As shown in fig. 4, the ordinate represents the phase, and the abscissa represents the pixel number in the direction of the driven electric field switch. When the insertion loss of the reference diffracted light needs to be compensated, the phase grating pattern parameter of the reference diffracted light, i.e., the slope k of the phase grating pattern (k = tan Φ), can be changed by adjusting the phase of each corresponding pixel on the LCOS panel 40 where the reference diffracted light is distributed. According to the formula: tsin θ = m λ; t is the grating period, theta is the diffraction angle, m is the diffraction order, and lambda is the incident wavelength of the diffracted light. It can be seen that changing the slope k of the phase grating pattern changes the period T of the grating structure (maximum phase modulation depth 2 pi). Therefore, under the condition that the diffraction order m and the incident wavelength lambda of the diffracted light are not changed, the diffraction angle theta of the diffracted light is changed, so that the reference diffracted light can be output by aiming at the reference output port 202, the reference diffracted light is ensured to be detected by the detection unit 50 as much as possible, and the insertion loss of the reference diffracted light is reduced. Therefore, the output position of the diffracted light can be changed by changing the diffraction angle of the reference light and the signal light, so that the corresponding insertion loss is reduced.
Therefore, in the wavelength selective switch provided in this embodiment, by providing a reference light and passing both the reference light and the signal light through the internal optical element of the wavelength selective switch, the insertion loss of each signal diffracted light is compensated based on changing the pattern parameter of the reference diffracted light phase grating to compensate the insertion loss of the reference diffracted light, so that the compensation precision is high, and the compensation effect caused by uneven temperature distribution or poor repeatability inside the wavelength selective switch is avoided. Compared with the prior art, the wavelength selective switch that this embodiment provided need not to control wavelength selective switch and can realize the insertion loss compensation that the temperature drifts and lead to for the constant temperature state, not only can reduce the consumption, improves job stabilization nature, moreover because set up reference light and occupy the device space very little, then can reduce the device volume to and reduce manufacturing cost.
Further, when it is determined that insertion loss compensation needs to be performed on a certain path of the signal diffraction light, the insertion loss of the signal diffraction light is compensated according to a phase shift amount to be compensated of the obtained path of the signal diffraction light, and a phase shift amount ρ of a pixel corresponding to the signal diffraction light distributed on the LCOS panel satisfies the following formula: ρ = (2 π xy σ)/λ;
wherein x is a pixel width, y is a pixel number, and σ is a correction amount of a phase grating pattern parameter of the reference diffracted light after the reference light insertion loss compensation, that is, a variation amount of a slope k of the phase grating pattern. And lambda is the wavelength of the central channel of each path of signal diffraction light distributed on the LCOS panel.
Based on the same inventive concept, the present embodiment further provides a method for compensating a temperature drift of a wavelength selective switch, referring to fig. 1-2, the method includes:
the method comprises the following steps: the illumination unit 10 provides reference light and signal light. That is, the laser 101 and the power detector 102 provide the reference light with stable wavelength, and the optical communication interface 103 provides the signal light.
Step two: the reference light and the signal light enter the optical conversion unit 30 through the reference input port 201 and the signal input port 211, respectively, and are converted into diffracted lights with different wavelengths through the optical conversion unit 30, that is: the reference diffraction light and each signal diffraction light with different wavelengths are transmitted to the LCOS panel 40 and distributed in the first area 401 and the second area 402. The reference diffracted light and each of the signal diffracted lights with different wavelengths are reflected by the LCOS panel 40 to the optical conversion unit 30, and are output by the reference output port 202 and the signal output port 212 after passing through the optical conversion unit 30.
Step three: the detection unit 50 detects whether the insertion loss of the reference diffracted light exceeds a preset range. The preset range is not limited in this embodiment, and the corresponding threshold range is different according to different application scenarios of optical communication, and generally, the variation of 0.1dB is used as a reference.
If not, the insertion loss compensation is not needed.
If so, adjusting the phase of each pixel corresponding to the reference diffraction light distribution on the LCOS panel 40, changing the pattern parameters of the reference diffraction light phase grating, and compensating the insertion loss of the reference diffraction light to a preset value according to the real-time monitoring result of the detection unit 50. Wherein the preset value is the initial light energy close to the reference light.
Step four: and calculating the phase shift amount to be compensated of each path of signal diffraction light according to the correction amount of the phase grating pattern parameter after the reference diffraction light is changed, and respectively adjusting the phase of each pixel corresponding to the distribution of the signal diffraction light on the LCOS panel 40 according to the phase shift amount so as to compensate the insertion loss of each path of signal diffraction light to a preset value.
In summary, in the wavelength selective switch provided in this embodiment, by providing the reference light, and passing both the reference light and the signal light through the internal optical element of the wavelength selective switch, the insertion loss of each signal diffracted light is compensated based on changing the phase grating pattern parameter of the reference diffracted light to compensate the insertion loss of the reference diffracted light, so that the compensation precision is high, and the wavelength selective switch does not need to be controlled to be in a constant temperature state, which not only can reduce power consumption, improve operating stability, but also can reduce manufacturing cost and reduce device size.
It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. It will be apparent to those skilled in the art that many changes and modifications can be made, or equivalents employed, to the presently disclosed embodiments without departing from the intended scope of the invention. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention will still fall within the protection scope of the technical solution of the present invention.
Claims (10)
1. A wavelength selective switch, comprising: the device comprises an illumination unit, an input and output unit, an optical conversion unit, a control unit with an LCOS panel and a detection unit;
the illumination unit is used for providing reference light and signal light;
the input and output unit comprises a reference input port, a reference output port, a signal input port and a plurality of signal output ports, the reference light enters the optical conversion unit through the reference input port, and the signal light enters the optical conversion unit through the signal input port;
the optical conversion unit is used for dispersing the reference light and the signal light, separating the reference light and the signal light into various paths of signal diffraction light and reference diffraction light with different wavelengths, and distributing the signal diffraction light and the reference diffraction light to different areas of the LCOS panel according to a wavelength sequence;
the LCOS panel is used for reflecting the reference diffraction light and each path of signal diffraction light to the optical conversion unit, and then outputting the reference diffraction light and each path of signal diffraction light through the reference output port and the corresponding signal output port respectively;
the detection unit is used for monitoring the light energy of the reference diffracted light output by the reference output port;
the LCOS panel is further configured to adjust the phase of each pixel corresponding to the distribution of the reference diffracted light on the LCOS panel according to the detection result of the detection unit, so as to change the phase grating pattern parameter of the reference diffracted light, and further change the diffraction angle of the reference diffracted light, so as to perform insertion loss compensation on the reference light; and, according to the correction amount of the phase grating pattern parameter of the reference diffracted light after the reference light insertion loss compensation, the phase shift amount to be compensated of each path of the signal diffracted light can be obtained, and the LCOS panel is further configured to adjust the phase of each corresponding pixel on the LCOS panel of the distribution of each path of the signal diffracted light to be compensated, and further change the diffraction angle of each path of the signal diffracted light, so as to perform insertion loss compensation on each path of the signal diffracted light to be compensated.
2. The wavelength selective switch of claim 1, wherein the illumination unit comprises a laser, a power detector, and an optical communication interface; wherein the content of the first and second substances,
the laser is used for providing the wavelength-stabilized reference light to the reference input port; the power detector is used for monitoring the power of the laser; the optical communication interface is used for providing the signal light in optical communication to the signal input port.
3. The wavelength selective switch of claim 1, wherein the input/output unit is an optical fiber array, and the reference input port, the reference output port, the signal input port, and the plurality of signal output ports are arranged in an array.
4. The wavelength selective switch of claim 1, wherein the optical conversion unit comprises: a polarizer, a cylindrical mirror, a lens, and a grating; wherein the content of the first and second substances,
the reference light and the signal light are converted into linearly polarized light through the polarizer, reflected to a lens through the cylindrical reflector, focused by the lens, enter the grating, and are diffracted and separated into various paths of signal diffraction light and reference diffraction light with different wavelengths after passing through the grating;
and the signal diffraction light and the reference diffraction light with different wavelengths sequentially pass through the lens and the cylindrical reflector and are reflected to different areas of the LCOS panel through the cylindrical reflector.
5. The wavelength selective switch according to claim 4, wherein each of the signal diffraction light and the reference diffraction light with different wavelengths is reflected by the LCOS panel to the cylindrical mirror, reflected by the cylindrical mirror to enter the polarizer, and outputted by the reference output port and each of the signal output ports after passing through the polarizer.
6. The wavelength selective switch of claim 1, wherein the detection unit comprises an energy detector, the reference diffracted light enters the energy detector after being output from the reference output port, and the energy detector detects light energy of the reference diffracted light.
7. The wavelength selective switch of claim 1, wherein when it is determined that the insertion loss compensation is required for a certain path of the signal diffracted light, the insertion loss of the signal diffracted light is compensated according to a phase shift amount to be compensated for when the path of the signal diffracted light is obtained, and a phase shift amount ρ of a corresponding pixel of the signal diffracted light distributed on the LCOS panel satisfies the following formula: ρ = (2 π xy σ)/λ;
wherein x is the pixel width, y is the pixel number, and σ is the correction quantity of the phase grating pattern parameter of the reference diffracted light after the reference light insertion loss compensation; and lambda is the wavelength of the central channel of each path of signal diffraction light distributed on the LCOS panel.
8. The wavelength selective switch of claim 1, wherein the reference light has a wavelength range of: 1500nm-1700 nm.
9. A wavelength selective switch temperature drift compensation method, which is implemented by using the wavelength selective switch according to any one of claims 1-8, and comprises:
the illumination unit provides reference light and signal light;
the reference light and the signal light respectively enter the optical conversion unit through the reference input port and the signal input port, are converted into diffracted lights with different wavelengths through the optical conversion unit, are transmitted to the LCOS panel of the control unit, and are distributed on different areas of the LCOS panel according to the wavelength sequence; the diffracted light with different wavelengths is reflected to the optical conversion unit by the LCOS panel, and is output through the reference output port and the corresponding signal output port respectively after passing through the optical conversion unit;
the detection unit detects whether the insertion loss of the reference diffracted light exceeds a preset range;
if so, adjusting the phase of each corresponding pixel of the reference diffraction light distribution on the LCOS panel to change the phase grating pattern parameter of the reference diffraction light, and further changing the diffraction angle of the reference diffraction light to compensate the insertion loss of the reference light to a preset value;
and obtaining a phase shift quantity to be compensated of each path of signal diffraction light according to the correction quantity of the phase grating pattern parameter of the reference diffraction light after the insertion loss compensation of the reference light, and respectively adjusting the phase of each corresponding pixel of the distribution of each path of signal diffraction light to be compensated on the LCOS panel according to the phase shift quantity so as to compensate the insertion loss of each path of signal diffraction light to a preset value.
10. The method for compensating for the temperature drift of the wavelength selective switch according to claim 9, wherein when it is determined that the insertion loss compensation needs to be performed on a certain path of the signal diffracted light, the insertion loss of the signal diffracted light is compensated according to a phase shift amount to be compensated for when the path of the signal diffracted light is obtained, and a phase shift amount ρ of a corresponding pixel of the signal diffracted light distributed on the LCOS panel satisfies the following formula: ρ = (2 π xy σ)/λ;
wherein x is the pixel width, y is the pixel number, and σ is the correction quantity of the phase grating pattern parameter of the reference diffracted light after the reference light insertion loss compensation; and lambda is the wavelength of the central channel of each path of signal diffraction light distributed on the LCOS panel.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102879864A (en) * | 2012-11-01 | 2013-01-16 | 武汉邮电科学研究院 | Wavelength shift detection and calibration method for LCOS (Liquid Crystal On Silicon) wavelength selection switch |
| CN104297857A (en) * | 2014-10-30 | 2015-01-21 | 武汉邮电科学研究院 | Method and device for adaptive adjustment of temperature of silicon-based liquid crystal wavelength selective switch |
| CN104583824A (en) * | 2012-07-19 | 2015-04-29 | 菲尼萨公司 | Polarization diverse wavelength selective switch |
| CN106416097A (en) * | 2014-03-04 | 2017-02-15 | 菲尼萨公司 | A calibration system for a wavelength selective switch |
| CN106772813A (en) * | 2016-12-16 | 2017-05-31 | 中央民族大学 | Resolution ratio wavelengthtunable selecting switch and control method based on phase grating array |
| CN108121036A (en) * | 2016-11-29 | 2018-06-05 | 华为技术有限公司 | A kind of wavelength-selective switches and light signal transmission system |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5707147B2 (en) * | 2011-01-24 | 2015-04-22 | 日立コンシューマエレクトロニクス株式会社 | Optical information reproducing method and optical information reproducing apparatus |
| US9046657B2 (en) * | 2011-12-22 | 2015-06-02 | Finisar Corporation | Systems and methods for reducing off-axis optical aberrations in wavelength dispersed devices |
| CN104777557B (en) * | 2015-04-29 | 2018-01-02 | 武汉邮电科学研究院 | Multiport variable bandwidth wavelength-selective switches based on LCOS |
| CN105182000B (en) * | 2015-05-30 | 2018-05-22 | 浙江大学 | Three optical path signal compensation systems and its method in optical MEMS accelerometer |
-
2021
- 2021-03-25 CN CN202110316927.6A patent/CN113985531B/en not_active Expired - Fee Related
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104583824A (en) * | 2012-07-19 | 2015-04-29 | 菲尼萨公司 | Polarization diverse wavelength selective switch |
| CN102879864A (en) * | 2012-11-01 | 2013-01-16 | 武汉邮电科学研究院 | Wavelength shift detection and calibration method for LCOS (Liquid Crystal On Silicon) wavelength selection switch |
| CN106416097A (en) * | 2014-03-04 | 2017-02-15 | 菲尼萨公司 | A calibration system for a wavelength selective switch |
| CN104297857A (en) * | 2014-10-30 | 2015-01-21 | 武汉邮电科学研究院 | Method and device for adaptive adjustment of temperature of silicon-based liquid crystal wavelength selective switch |
| CN108121036A (en) * | 2016-11-29 | 2018-06-05 | 华为技术有限公司 | A kind of wavelength-selective switches and light signal transmission system |
| CN106772813A (en) * | 2016-12-16 | 2017-05-31 | 中央民族大学 | Resolution ratio wavelengthtunable selecting switch and control method based on phase grating array |
Non-Patent Citations (1)
| Title |
|---|
| 《Research of two-dimensional beam steering in LCOS-based wavelength selective switch》;DONGTANG YANG etal;《Applied Optics》;Optical Society of America;20150506;第54卷(第14期);全文 * |
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