CN114815076A

CN114815076A - Multistage MEMS optical switch unit and optical cross device

Info

Publication number: CN114815076A
Application number: CN202210148635.0A
Authority: CN
Inventors: 闫云飞; 赵晗; 冯志勇; 邹冰
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2017-10-30
Filing date: 2017-10-30
Publication date: 2022-07-29
Also published as: CN111247472A; CN111247472B; WO2019084710A1

Abstract

A multi-stage MEMS optical switch cell and an optical crossbar device. In the multi-stage MEMS optical switch unit, a cantilever beam is used for keeping the micro-mirror in an initial state when no acting force is generated by N electrodes; when at least one electrode in the N electrodes generates acting force, the micro-mirror is enabled to be in a target deflection state; when the force is zero, the micro-mirror is restored to the initial state; at least one electrode in the N electrodes is used for generating acting force and controlling the micro-mirror to enter a deflection state; a micromirror for entering a deflected state under the force of at least one of the N electrodes; at least one of the M blockers for blocking the micro-mirror such that the micro-mirror stops to a target deflection state.

Description

Multistage MEMS optical switch unit and optical cross device

Technical Field

The embodiment of the application relates to the field of optical communication, in particular to a multi-level Micro-Electro-Mechanical System (MEMS) optical switch unit and an optical cross device.

Background

In recent years, with the development of Optical switching technology and the large-scale application of Wavelength Division Multiplexing (WDM), the capacity of Optical Network node equipment is increasing, and higher requirements are put forward on the survivability of the Network, and Optical Cross-connect (OXC) integrates transmission and switching, has the advantages of large transmission capacity, flexible networking, expandability and reconfigurability of the Network, easy upgrading, transparent transmission of signals with different rate levels in various formats, capability of simultaneously adapting to the increasing requirements of user signal types and service types, and the like, and is important node equipment for forming an Optical Transport Network (OTN).

The key point for realizing the OXC is to develop and apply advanced optical devices, wherein the optical switches include mechanical optical switches, polymer switches (polymers), semiconductor optical switches, Planar Lightwave Circuits (PLCs), MEMS and the like, and particularly, the technology of the MEMS optical switches is rapidly developed. The OXC optical switch is developing towards the direction of integrating the advantages of low loss, high isolation, flexibility, dynamics, low power consumption, small volume, low cost and the like.

Most of the current commercialized products are OXCs based on MEMS technology. The OXC optical switch matrix is manufactured by utilizing the micro-mirror, and the micro-mirror can realize the on-off function of an optical switch by adopting an up-down folding mode, a left-right moving mode or a rotating mode. The optical switch manufactured by the MEMS technology integrates a mechanical structure, a micro-actuator and a micro-mirror on the same substrate, and has the advantages of compact structure, light weight and easy expansion. MEMS optical switches may include two-Dimensional (2-Dimensional, 2D) and three-Dimensional (3-Dimensional, 3D) based MEMS optical switches. The 2D MEMS optical switch is of a digital structure, and the 3D MEMS optical switch is of an analog structure.

In the 2D MEMS optical switch, all the micro mirrors and the input/output optical fibers are located on the same plane, and the micro mirrors are erected and tilted by the electrostatic actuator or the micro mirrors are in the optical path and pop-up optical path in the "see-saw" manner, so as to realize the "on" and "off" functions, so the 2D structure is also called as a digital structure.

An NxN 2D optical switch requires N ² The 2D structure of the micro-mirror has the advantages of simple control and the defect that the number of the exchange ports cannot be made large due to the limitation of the optical path and the area of the micro-mirror. In the 3D structure, all the micromirrors are located on two opposite planes, and the switching of the optical path is realized by changing different positions of each micromirror.

An nxn 3D optical switch only needs 2N micromirrors, but each micromirror needs at least N precisely controllable movable positions, so the 3D structure is also called analog type. In contrast to the 2D architecture, the 3D architecture has the advantage that the number of switching ports can be made very large, allowing for thousands of ports of switching capability.

In large-scale OXC, a 3D MEMS structure is mainly applied, and the 3D MEMS is a simulated micro-mirror whose switched state is a suspended state, and there are problems of long oscillation time and slow switching speed in switching, for example, in switching of a 3D analog MEMS, when a micro-mirror is controlled to deflect to a design position, the micro-mirror is finally in the suspended state, so that the micro-mirror can reach a stable state after oscillating for a certain time. The oscillation time of a micro-mirror is typically greater than 10 milliseconds (ms), limited by the oscillation time of the micro-mirror, and the switching speed of the micro-mirror is typically on the order of 10ms or 100 ms. The state switching time of the micro-mirrors is severely affected, resulting in the restricted OXC switching speed of 3D analog MEMS based MEMS to the MEMS switching speed.

In addition, the MEMS structure provided by the prior art is an analog MEMS, and also has a problem that a control mechanism and a driving structure are quite complicated, and the operating mode thereof is an analog type, so that a control circuit needs to accurately control a voltage applied to an electrode to control a deflection state of a micro-mirror, and the control part is complicated and has high cost.

Disclosure of Invention

The embodiment of the application provides a multistage MEMS optical switch unit and an optical cross device, which can realize a multistage digital optical switching engine and simplify the deflection state control of a micro control mirror.

In a first aspect, an embodiment of the present application provides a multi-stage MEMS optical switch unit, including: the micro-mirror comprises a micro-mirror, a cantilever beam, N electrodes and M stoppers, wherein N, M are positive integers which are greater than or equal to 2, and the cantilever beam is used for enabling the micro-mirror to keep an initial state when no force is generated by the N electrodes; causing the micro-mirror to be in a target deflection state when at least one of the N electrodes generates a force; when the acting force is zero, the micro mirror is restored to the initial state; at least one electrode in the N electrodes is used for generating acting force and controlling the micro mirror to enter a deflection state; the micro-mirror is used for entering a deflection state under the action of at least one electrode in the N electrodes; at least one blocker of the M blockers to block the micro-mirror such that the micro-mirror stops to a target deflection state.

In an embodiment of the present application, the multi-stage MEMS optical switch unit may include: the micro-mirror comprises a micro-mirror, a cantilever beam, N electrodes and M stoppers; the cantilever beam is used for keeping the micro-reflector in an initial state when the N electrodes do not generate acting force; enabling the micro-mirror to be in a target deflection state under the action of the acting force generated by the electrode; when the force is zero, the micro-mirror is restored to the initial state; the electrode is used for generating acting force and controlling the micro-mirror to enter a deflection state; the micro-mirror is used for entering a deflection state under the acting force of the electrode; a stopper for stopping the micromirror such that the micromirror stops to a target deflection state. Because in the embodiment of the application, acting force can be generated through multiple electrodes to control the micro-reflector to be in a target deflection state, the embodiment of the application can realize a multi-stage digital optical switching engine, and a plurality of stoppers are arranged in a multi-stage MEMS optical switching unit structure, so that the oscillation time of the micro-reflector during switching is shortened, and the micro-reflector has high switching speed. Because the multi-stage MEMS optical switch unit is provided with a plurality of control electrodes and blocking columns, the micro-mirror has a plurality of deflection states, and the large-port OXC is easy to realize.

In one possible design of the first aspect of the present application, the cantilever is specifically configured to maintain the micromirror in an initial state when no voltage is applied to any of the N electrodes; causing the micro-mirror to be in a target deflection state when at least one of the N electrodes generates an electrostatic force; when the electrostatic force is zero, restoring the micro mirror to the initial state; at least one of the N electrodes is specifically used for generating electrostatic force to the micro-mirror after voltage is applied. In the embodiment of the present application, at least one of the N electrodes may apply a voltage, so as to generate an electrostatic force on the micromirror, and the micromirror may deflect under the electrostatic force.

In one possible design of the first aspect of the present application, the multi-stage MEMS optical switch unit further includes: the device comprises N through silicon vias and an electrode control circuit, wherein the N electrodes are respectively connected with the electrode control circuit through the N through silicon vias; the electrode control circuit is used for controlling at least one electrode in the N electrodes to generate acting force. The electrode can be connected with welding points on the other side of the substrate through the silicon through holes, the electrode control circuit is connected with the electrode through the welding points, and the electrode control circuit can control the voltage on the N electrodes through the silicon through holes.

In one possible design of the first aspect of the present application, N and M are equal, and there is a one-to-one correspondence between the N electrodes and the M blockers; the N electrodes are uniformly distributed on the substrate, and the M stoppers are uniformly distributed on the substrate; when the ith electrode generates acting force, the ith stopper provides a block for the micro-mirror, so that the micro-mirror stops at the target deflection state, and i is a positive integer less than or equal to N. The number M of the stoppers may be equal to the number N of the electrodes, for example, each stopper may be correspondingly provided with one stopper, for example, the ith stopper may be provided around the ith electrode, and then the ith stopper may be used to block the micromirror when the ith electrode generates the electrostatic force, so that the oscillation time when the micromirror switches is shortened. The processing difficulty of the multi-stage MEMS optical switch unit can be simplified through the one-to-one corresponding arrangement relationship between the electrodes and the stoppers.

In one possible design of the first aspect of the present application, when the substrate is a circular structure, the N electrodes are uniformly distributed around a central position of the circular structure, and an included angle between two adjacent electrodes in the N electrodes is equal to 360 °/N. The included angle between two adjacent electrodes in the N electrodes is equal to 360 degrees/N, and the electrodes are uniformly distributed around the center position of the circular structure, so that the action direction of the electrodes on the electrostatic force of the micro-reflector is convenient to control.

In one possible design of the first aspect of the present application, the micro mirror includes: a circular mirror plate.

In one possible design of the first aspect of the present application, the number of the cantilever beams is K, where K is a positive integer and K is smaller than N; the M is greater than the N. The number of the cantilever beams needs to comprehensively consider the deflection direction number, the switching speed and the precision requirement of the micro-reflector. It is understood that if M is larger than N, the deflection of the micro mirror may be blocked simultaneously by at least two blockers.

In a second aspect, an embodiment of the present application provides an optical cross-connect apparatus, including: a multi-stage MEMS switch array, the multi-stage MEMS switch array comprising: a multi-stage MEMS optical switch unit as claimed in any one of the preceding first aspects. Because in the embodiment of the application, acting force can be generated through multiple electrodes to control the micro-reflector to be in a target deflection state, the embodiment of the application can realize a multi-stage digital optical switching engine, and a plurality of stoppers are arranged in a multi-stage MEMS optical switching unit structure, so that the oscillation time of the micro-reflector during switching is shortened, and the micro-reflector has high switching speed. Because the multi-stage MEMS optical switch unit is provided with a plurality of control electrodes and blocking columns, the micro-mirror has a plurality of deflection states, and the large-port OXC is easy to realize.

In one possible design of the second aspect of the present application, the multi-stage MEMS switch array is specifically a first multi-stage MEMS switch array, or a second multi-stage MEMS switch array; the optical cross-connect apparatus further comprises: the optical fiber coupling device comprises an input end optical fiber array, an input end collimator array, a lens, an output end collimator array and an output end optical fiber array, wherein the input end optical fiber array is used for coupling and inputting light beams; the input end collimator array is used for collimating the light beams output from the input end optical fiber array; the first multi-stage MEMS switch array comprising S first multi-stage MEMS optical switch cells as in any one of the previous first aspects, S being a positive integer; the first multi-stage MEMS switch array is used for mapping the light beams output by the input end collimator array to the second multi-stage MEMS switch array through the lens; the second multi-stage MEMS switch array comprising T second multi-stage MEMS optical switch cells as in any one of the previous first aspects, T being a positive integer; the second multi-stage MEMS switch array is used for outputting the light beams from the first multi-stage MEMS optical switch array to the output end collimator array; the output end collimator array is used for collimating the light beams output from the second multistage MEMS switch array; and the output end optical fiber array is used for coupling and outputting light beams. By the optical crossing device, the optical signals can be switched rapidly and nondestructively.

In one possible design of the second aspect of the present application, the input end optical fiber array includes: the position layout of each input port corresponds to the mapping position of the first multistage MEMS optical switch unit one by one; the output end optical fiber array comprises: the position layout of each output port corresponds to the mapping position of the second multistage MEMS optical switch unit one by one; each first multistage MEMS optical switch unit can switch beams to T directions, and the arrangement mode of the first multistage MEMS optical switch units is determined by the switching direction and the switching angle of the second multistage MEMS optical switch unit and the focal length of a lens; each second multistage MEMS optical switch unit can switch the wave beam to S directions, and the arrangement mode of the second multistage MEMS optical switch units is determined by the switching direction and the switching angle of the first multistage MEMS optical switch unit and the focal length of the lens.

In one possible design of the second aspect of the present application, S is equal to T. The number of input ports and output ports in the input end optical fiber array is equal, and the number of first multi-stage MEMS optical switch units contained in the first multi-stage MEMS switch array is also equal to that of second multi-stage MEMS optical switch units contained in the second multi-stage MEMS switch array. Without limitation, the number of input ports may be different from the number of output ports.

In one possible design of the second aspect of the present application, the arrangement of the multi-stage MEMS optical switch units on the multi-stage MEMS switch array is a ring. N multi-stage MEMS optical switch units on the multi-stage MEMS switch array are distributed in an annular shape, and the N multi-stage MEMS optical switch units share N micro mirrors.

In one possible design of the second aspect of the present application, when a current multi-stage MEMS optical switch unit in the multi-stage MEMS switch array is switched to a target multi-stage MEMS optical switch unit, the optical beam switching adopts a straight-line switching path, or a zigzag-line switching path, or an arc-shaped switching path. The speed of optical signal switching can be improved by adopting different switching of the multi-stage MEMS switch array.

In one possible design of the second aspect of the present application, the polyline switching path includes: a two-step linear switching path passing through a center point location of the multi-stage MEMS switch array. The broken line switching path adopted by the multistage MEMS switch array passes through the central point position, and the optical signal switching can be completed through two-step linear switching.

Drawings

Fig. 1 is a schematic top view of a multi-stage MEMS optical switch unit according to an embodiment of the present disclosure;

FIG. 2 is a schematic diagram of a side view of a multi-stage MEMS optical switch unit provided in an embodiment of the present application;

fig. 3 is a schematic diagram of an electrode blocked by a stopper according to an embodiment of the present disclosure;

fig. 4 is a schematic structural diagram of an optical cross apparatus provided in the embodiment of the present application;

fig. 5 is a schematic structural diagram of another optical cross apparatus provided in the embodiment of the present application;

fig. 6 is a schematic diagram illustrating a layout of a multi-stage MEMS optical switch unit in an optical crossbar device according to an embodiment of the present application;

fig. 7 is a schematic diagram illustrating another layout of a multi-stage MEMS optical switch unit in an optical crossbar device according to an embodiment of the present application;

FIG. 8 is a schematic diagram of a beam switching path in an optical cross apparatus according to an embodiment of the present disclosure;

FIG. 9 is a schematic diagram of another optical beam switching path in the optical cross apparatus according to the embodiment of the present application;

fig. 10 is a schematic diagram of another optical beam switching path in the optical cross apparatus according to the embodiment of the present application.

Detailed Description

Embodiments of the present application are described below with reference to the accompanying drawings.

The terms "first," "second," and the like in the description and in the claims of the present application and in the above-described drawings are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and are merely descriptive of the various embodiments of the application and how objects of the same nature can be distinguished. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of elements is not necessarily limited to those elements, but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

First, a multi-stage MEMS optical switch unit provided in the embodiments of the present application is illustrated, and the multi-stage MEMS optical switch unit can be applied to an optical cross apparatus. Referring to fig. 1 and fig. 2, a multi-stage MEMS optical switch unit according to an embodiment of the present disclosure may include: the micromirror 101, the substrate 102, the cantilever beam 103, the N electrodes 104 (e.g., 1041-,

the micro-mirror 101 is movably connected with the substrate 102 through a cantilever beam 103;

a cantilever beam 103, which is used for keeping the micro mirror 101 in an initial state when no force is generated by the N electrodes 104; causing the micro-mirror 101 to be in a target deflection state upon a force generated by at least one of the N electrodes 104; when the acting force is zero, the micro mirror 101 is restored to the initial state;

a cavity space is formed between the micro-mirror 101 and the substrate 102, the N electrodes 104 and the M stoppers 105 are arranged in the cavity space, and the N electrodes 104 and the M stoppers 105 are fixed on the substrate;

at least one of the N electrodes 104 for generating a force to control the micro mirror 101 to enter a deflection state;

a micromirror 101 for entering a deflected state under the force of at least one of the N electrodes 104;

at least one of the M blockers 105 for blocking the micro mirror 101 so that the micro mirror stops to a target deflection state.

The movable connection established between the micro mirror 101 and the substrate 102 can also be referred to as a movable connection, that is, the micro mirror 101 is connected with the cantilever beam 103, the cantilever beam 103 has ductility, and the cantilever beam 103 is connected with the substrate 102.

It should be noted that in the embodiment of the present application, one electrode of the N electrodes 104 may generate the force, or two or more adjacent electrodes may generate the force simultaneously, and the micro mirror 101 may enter the deflection state under the force of one electrode or multiple electrodes. Similarly, there may be one stopper out of the M stoppers 105 to block the micro mirror, or there may be two or more stoppers to block the micro mirror at the same time, which is not limited herein.

In some embodiments of the present application, a cantilever beam 103 for maintaining the micromirror 101 in an initial state when no voltage is applied to any of the N electrodes 104; causing the micro-mirror 101 to be in a target deflection state when at least one of the N electrodes 104 generates an electrostatic force; when the electrostatic force is zero, the micromirror 101 is restored to the initial state;

at least one of the N electrodes 104 is used to generate an electrostatic force on the micro-mirror 101 upon application of a voltage.

The micromirror 101 is configured to enter a deflection state under an electrostatic force. In this embodiment, the electrodes and the stoppers are both disposed in a cavity space formed by the micro mirror and the substrate, the deflection of the micro mirror can be controlled by an electrostatic force generated by at least one of the N electrodes, at least one of the M stoppers can be used to block the deflection of the mirror, so that the micro mirror stops to a target deflection state, the number M of the stoppers can be equal to the number N of the electrodes, or the number M of the stoppers is greater than the number N of the electrodes, which is not limited herein.

It should be noted that, in the embodiment of the present application, the applied force generated by the electrode may specifically be an electrostatic force, and the deflection of the micro mirror is controlled by the electrostatic force, and the electrode may also control the deflection of the micro mirror in a thermal driving manner, for example, the electrode generates thermal energy by applying current, and drives the cantilever beam to generate torque by the thermal energy, and then controls the deflection of the micro mirror by the torque.

In the prior art, the large-port OXC uses a 3D analog MEMS chip as an optical switching engine, and the port switching speed is limited by the switching speed of a micro-mirror, so that the switching speed of the OXC is difficult to improve. In the embodiment of the invention, electrostatic force can be generated by multiple electrodes to control the micro-mirror to be in a target deflection state, so that the embodiment of the invention can realize a multi-stage digital optical switching engine, a plurality of stoppers (also called blocking columns) are arranged in the structure of a multi-stage MEMS optical switching unit, and the stoppers and the blocking columns are not distinguished in the subsequent embodiment, so that the oscillation time of the micro-mirror during switching is shortened, and the multi-stage MEMS optical switching unit has high switching speed, is used as a digital chip, and has the switching speed far higher than that of an analog MEMS chip, meanwhile, the control circuit of the digital chip is simpler, and the system debugging and assembling are more convenient; the multi-stage MEMS optical switch unit is provided with a plurality of control electrodes and a plurality of blocking columns, so that the micro-mirror has a plurality of deflection states, and the large-port OXC is easy to realize. The OXC based on the multi-stage MEMS optical switch unit has the advantages of high switching speed, low loss, uncorrelated polarization and large port number, wherein the uncorrelated polarization is light in any polarization state, and the multi-stage MEMS optical switch unit can carry out optical transmission processing.

In some embodiments of the present application, as shown in FIG. 2, base 102 is coupled to an end of cantilever beam 103;

the other end face of the micro mirror 101 is connected with the other end face of the cantilever beam 103, and the two end faces of the cantilever beam 103 are symmetrically arranged.

Wherein, the substrate 102 can provide the movable supporting force of the cantilever beam 103, so that the micro mirror 101 can establish a movable connection with the substrate 102 through the cantilever beam 103.

In some embodiments of the present application, N and M are equal, with one-to-one correspondence between the N electrodes and the M blockers;

the N electrodes are uniformly distributed on the substrate, and the M stoppers are uniformly distributed on the substrate;

when the ith electrode generates acting force, the ith stopper provides a block for the micro-mirror, so that the micro-mirror stops at a specific deflection state, and i is a positive integer less than or equal to N.

The number M of the stoppers may be equal to the number N of the electrodes, for example, each stopper may be correspondingly provided with one stopper, for example, the ith stopper may be provided around the ith electrode, and then the ith stopper may be used to block the micromirror when the ith electrode generates the electrostatic force, so that the oscillation time of the micromirror during switching is shortened. The processing difficulty of the multi-stage MEMS optical switch unit can be simplified through the one-to-one corresponding arrangement relationship between the electrodes and the stoppers.

In some embodiments of the present application, when the substrate is a circular structure, the N electrodes are uniformly distributed around a central position of the circular structure, and an included angle between two adjacent electrodes in the N electrodes is equal to 360 °/N.

As shown in fig. 1, the angle between two adjacent electrodes of the N electrodes is equal to 360 °/N, and the electrodes are uniformly distributed around the central position of the circular structure, so as to facilitate the control of the acting direction of the electrode on the electrostatic force of the micromirror.

In some embodiments of the present application, as shown in fig. 2, the multi-stage MEMS optical switch unit further includes: n through-silicon vias 107 and electrode control circuitry, wherein,

the N electrodes are respectively connected with an electrode control circuit through N silicon through holes 107;

and the electrode control circuit is used for controlling at least one electrode in the N electrodes to generate acting force.

It should be noted that the electrode control circuit is not shown in fig. 2, the electrode may be connected to the pads 106 on the other side of the substrate through the through-silicon vias, the electrode control circuit is connected to the electrode 104 through the pads 106, and the electrode control circuit may control the voltages on the N electrodes through the through-silicon vias.

In some embodiments of the present application, a micro mirror includes: a circular mirror plate. For example, the micro-mirror may comprise a circular mirror plate, and the mirror plate included in the micro-mirror in the embodiment of the present application may also be flexibly configured according to the actual scene, which is not limited herein. In other embodiments of the present application, as shown in FIG. 2, the micromirrors can reflect the light beams incident on their surfaces by selecting appropriate reflective films 108 on the mirrors.

In some embodiments of the present application, the number of the cantilever beams is K, K is a positive integer, and K is less than N; m is greater than N. The number of the cantilever beams needs to comprehensively consider the deflection direction number, the switching speed and the precision requirement of the micro-reflector. It is understood that if M is larger than N, the deflection of the micro mirror may be blocked simultaneously by at least two blockers.

In the multi-stage MEMS optical switch unit provided in the embodiment of the present application, the multi-stage MEMS optical switch unit includes a micro mirror, K cantilever beams, N electrodes, M stoppers, and the like, and can implement at least one state deflection switching in each of N directions of a light beam. The micro-mirror is used for reflecting light beams incident to the mirror surface and is connected to the substrate by K cantilever beams. The number of K is a positive integer larger than 4 and smaller than N, the cantilever beam can connect the micro-reflector on the substrate in a suspension manner, and the elastic cantilever beam can enable the micro-reflector to deflect in N directions when power is applied. N electrodes are distributed under the micro-mirror, and the micro-mirror generates N direction inclination by applying power. The M blockers are distributed under the micro-mirror, and determine the final tilt angle and the switching speed of the micro-mirror after power-on.

Next, a schematic description is given of an application scenario of the multi-stage MEMS optical switch unit, and shown in fig. 1 is a single multi-stage MEMS optical switch unit, also referred to as a single multi-stage digital MEMS lens, where the structure of the whole multi-stage digital MEMS lens may include: a mirror (mirror)101, a substrate (substrate)102, k cantilevers 103, N electrodes (electrodes) 104, and M stopper posts (stoppers) 105. As shown in fig. 2, the entire multi-stage digital MEMS lens may further include: solder 106, through silicon via 107, reflective film 108.

In the multi-stage MEMS optical switch unit provided in the embodiment of the present application, the reflective mirror has N working states, and the state switching time is less than 1ms, so the state switching time of the multi-stage MEMS optical switch unit provided in the embodiment of the present application is much less than the switching time (about 100ms) of the continuously adjustable MEMS mirror structure in the prior art. As shown in fig. 1, the micromirror structure comprises a circular mirror plate, and the micromirror can reflect the light beam incident on its surface by selecting a suitable reflective film on the mirror plate. As shown in fig. 1 and 2, k cantilevers connect the mirror to a substrate, and the mirror is spaced from the substrate directly below to form a cavity space, which may also be referred to as a "dead space", and the k cantilevers make the mirror still parallel to the X-Y plane in the absence of any applied voltage to the electrodes. The k cantilever beams have certain ductility, and the mirror surface can move under the condition of stress. The number k of the cantilever beams is more than 4 and less than the number N of the electrodes, wherein N is the number of the rotating directions of the micro-reflector, and the specific number of the electrodes comprehensively considers the number of the deflection directions, the switching speed and the precision requirement of the lens. N electrodes are uniformly distributed on the surface of the substrate below the lens, and the included angle between every two electrodes is 360 degrees/N, wherein 360 degrees represents 360 degrees of the circumference. The electrodes can generate electrostatic force to the mirror surface above the mirror surface after voltage is applied, the lens is provided with the electrostatic force which is downward along the Z direction, the lens is inclined towards the Z axis direction after being stressed, the N electrodes are connected with welding points on the other side of the substrate through a silicon through hole technology, the electrode control circuit is connected with the electrodes in the micro-reflector structure through the welding points, and the electrostatic force is controlled to be applied to the mirror surface in any direction by controlling the power-on condition of different electrodes, so that the inclined direction of the lens is controlled. When the inclination angle of the lens is changed, the direction of the reflected light beam is correspondingly changed. The lower end of the lens is uniformly distributed with M blocking columns, as shown in figure 2, when a certain electrode is electrified, the lens is inclined under the action of electrostatic force in the direction of the electrode, the lens stops inclining after touching the blocking columns, and the mirror surface state at the moment is the corresponding lens state when the electrode is electrified.

As shown in FIG. 3, the stop columns determine the tilt of the mirror, the M stop columns determine the total number of N deflection directions of the mirror, and the height and distance from the center position of the stop columns determine the angle of tilt of the mirror during deflection. The existence of the blocking columns greatly reduces the damping motion time when the lens moves to the final state, and improves the switching speed between the micro-reflector states. The digital micro-mirror shown in fig. 1 controls the deflection state of the micro-mirror by controlling the power-on state of the electrode below the micro-mirror structure, so as to control the reflection direction of the light beam incident on the micro-mirror, the reflected light beam can deflect in N directions, each direction can deflect a preset angle, and a total of N reflection states can be provided for the same incident light beam.

In the foregoing application, the structure of the multi-stage MEMS optical switch unit is exemplified, and a brand new optical path design is performed for the relevant characteristics of the multi-stage MEMS optical switch unit, so that the multi-stage MEMS optical switch unit can be applied to the OXC module. Meanwhile, special design is carried out on parts such as a multistage MEMS optical switch unit which can generate a plurality of deflection states and strict incident delivery requirements. The resulting OXC device forms an optical switching engine based on multi-stage digital MEMS chips, distinct from conventional MEMS-based OXC modules.

The following schematically illustrates an optical cross apparatus provided in an embodiment of the present application, where the optical cross apparatus includes: a MEMS switch array, the multi-stage MEMS switch array may include: such as the aforementioned multi-stage MEMS optical switch cell of fig. 1-2.

In some embodiments of the present application, the multi-stage MEMS switch array is embodied as a first multi-stage MEMS switch array, or a second multi-stage MEMS switch array;

as shown in fig. 4 and 5, the optical cross apparatus provided in the embodiment of the present application further includes: an input end fiber array, an input end collimator array, a lens, an output end collimator array and an output end fiber array, wherein,

the input end optical fiber array is used for coupling and inputting light beams;

the input end collimator array is used for collimating the light beams output from the input end optical fiber array;

a first multi-stage MEMS switch array including S first multi-stage MEMS optical switch units, the first multi-stage MEMS optical switch units being the multi-stage MEMS optical switch units shown in the foregoing fig. 1 and 2, S being a positive integer; the first multi-stage MEMS switch array is used for mapping the light beams output by the input end collimator array to the second multi-stage MEMS switch array through a lens;

a second multi-stage MEMS switch array including T second multi-stage MEMS optical switch units, the second multi-stage MEMS optical switch units being the multi-stage MEMS optical switch units shown in the foregoing fig. 1 and fig. 2, T being a positive integer; a second multi-stage MEMS switch array for outputting the light beams from the first multi-stage MEMS optical switch array to an output collimator array;

an output collimator array for collimating the light beams output from the second multi-stage MEMS switch array;

and the output end optical fiber array is used for coupling and outputting the light beams.

As shown in fig. 4 and 5, the first multi-stage MEMS optical switch array includes a plurality of first multi-stage MEMS optical switch units, which are abbreviated as MEMS1 in fig. 4, the first multi-stage MEMS optical switch unit in fig. 5 may also be referred to as a "first multi-stage digital MEMS optical switch", and similarly, the second multi-stage MEMS switch array includes a plurality of second multi-stage MEMS optical switch units, which are abbreviated as MEMS2 in fig. 4, and the second multi-stage MEMS optical switch unit in fig. 5 may also be referred to as a "second multi-stage digital MEMS optical switch".

In some embodiments of the present application, an input optical fiber array, comprises: the position layout of each input port corresponds to the mapping position of the first multistage MEMS optical switch unit one by one;

the output end optical fiber array comprises: the position layout of each output port corresponds to the mapping position of the second multistage MEMS optical switch unit one by one;

each first multistage MEMS optical switch unit can switch beams to T directions, and the arrangement mode of the first multistage MEMS optical switch units is determined by the switching direction and the switching angle of the second multistage MEMS optical switch unit and the focal length of the lens;

each second multistage MEMS optical switch unit can switch the wave beam to S directions, and the arrangement mode of the second multistage MEMS optical switch units is determined by the switching direction and the switching angle of the first multistage MEMS optical switch unit and the focal length of the lens.

In an embodiment of the present application, an input end fiber array and an input end collimator array collimate S (positive integer) input beams, mapping beam waist positions to a first multi-stage MEMS switch array.

The first multi-stage MEMS switch array may include S first multi-stage MEMS optical switch units (simply referred to as switch units), each of which may switch a light beam to T (positive integer) directions, each of which is capable of switching at least one set angle; the arrangement mode of the S switch units is determined by the switching direction and the switching angle of the switch units in the second multi-stage MEMS switch array. The arrangement direction of the S switch units corresponds to the switching direction of the second multi-stage MEMS switch array one by one.

The first multi-stage MEMS switch array and the second multi-stage MEMS switch array are respectively located at the front focal plane and the rear focal plane of the lens, the beam waist of a light beam on the first multi-stage MEMS switch array is mapped to the second multi-stage MEMS switch array, light spot change is achieved, any micro-mirror on the first multi-stage MEMS switch array deflects to the same direction and angle, the light beam is mapped to the same position on the second multi-stage MEMS switch array, and the light beam is mapped to a switch unit at the same position on the second multi-stage MEMS switch array.

The second multi-stage MEMS switch array comprises T second multi-stage MEMS optical switch units (switch units for short); each switching unit can switch the light beam to S (positive integer) directions, and each direction can switch at least one set angle; the arrangement mode of the T switch units is determined by the switching direction and the switching angle of the switch units in the first multi-stage MEMS switch array. The arrangement direction of the T switch units corresponds to the switching direction of the first multi-stage MEMS switch array one by one.

The output end optical fiber array and the output end collimator array collimate the T (positive integer) output light beams, and the T light beams from the second multistage MEMS switch array are received and coupled out.

In some embodiments of the present application, S is equal to T. That is, the number of input ports and output ports in the input end optical fiber array is equal, and the number of first multi-stage MEMS optical switch units included in the first multi-stage MEMS switch array is also equal to the number of second multi-stage MEMS optical switch units included in the second multi-stage MEMS switch array. Without limitation, the number of input ports may be different from the number of output ports.

In some embodiments of the present application, the arrangement of the multi-stage MEMS optical switch units on the multi-stage MEMS switch array is a ring. As shown in fig. 6, N multi-stage MEMS optical switch units on the multi-stage MEMS switch array are distributed in a ring shape, and the N multi-stage MEMS optical switch units share N micromirrors. In the figure, there may be N fixed angles for each multi-stage MEMS optical switch cell, and different tilt angles for the multi-stage MEMS optical switch cells, so that the multi-stage MEMS optical switch cells have different tilt directions.

Further, in some embodiments of the present application, when a current multi-stage MEMS optical switch unit in the multi-stage MEMS switch array is switched to a target multi-stage MEMS optical switch unit, the beam switching adopts a straight switching path, or a zigzag switching path, or an arc switching path.

In the embodiment of the present application, the light beam switching of the multi-stage MEMS optical switch unit may take various paths, for example, a straight line switching path, a zigzag line switching path, or an arc switching path may be adopted. As shown in fig. 8-10, respectively.

Further, in some embodiments of the present application, the polyline switching path includes: a two-step linear switching path passing through a center point location of the multi-stage MEMS switch array.

Referring to fig. 7 to fig. 10, a lossless switching manner of the multi-stage MEMS optical switch unit according to the embodiment of the present invention is illustrated, and fig. 7 is taken as an example, in which 1 circle represents one switch unit. Fig. 8 shows a straight switching path, fig. 9 shows a broken switching path, and fig. 10 shows an arc switching path. In the prior art, an OXC switch needs to be switched according to a specific path in order to avoid the influence of switching light beams on a communication port. Switching from an existing port to a target port typically requires 3-5 switching procedures. The switching speed of the OXC switch in the embodiments of the present application is typically 3-5 times the switching speed of the switching unit. For the annular layout of the optical switch unit, since the switching path does not pass through other ports, only one switching process is needed to switch from any port to the target port, i.e. the OXC switching speed is reduced to be equal to the switching speed of the switch unit.

The embodiment of the application also provides a fast lossless switching mode which is sensitive to the crosstalk requirement and lossless switching between adjacent ports. The multi-stage MEMS switch array employs the ring layout in the previous embodiment. The switch can be from the switch port to the switch array center point and then to the target port. The switching speed of the OXC switch is 2 times the switching speed of the switching unit. Considering the situation that several ports switch simultaneously, an arc-shaped switching path can also be adopted to avoid crosstalk between several ports that are switched simultaneously. And meanwhile, the switching speed of the OXC switch is improved to be less than 2 times of the switching speed of the switch unit.

The embodiment of the application also provides an arrangement layout mode and a lossless switching mode of the OXC switch units. The layout of the OXC switch units is the installation annular or near annular arrangement, and a two-step or one-step direct switching mode from pre-switching ports to target ports is adopted, so that the efficiency of optical path switching is improved.

The embodiment of the application provides a digital multi-stage MEMS optical switch unit, which has two characteristics of rapidness and multi-state at the same time; the embodiment of the application also provides a fast optical switch device, and the adoption of the multi-state and high-speed switch unit can realize the high-speed OXC switch device with large port number; the application provides a fast lossless optical switch, a switch array layout and a switching mode, and the switching speed of the existing OXC switch device can be further improved; through the high-speed, many state switch unit that aforementioned propose, quick optical switch device and quick lossless switching mode can break through the dilemma that current OXC port number and switching speed restrict each other, realize the high-speed OXC of big port, help very much to promoting current network and cluster optical switching efficiency.

Next, an example of an optical cross-connect device implemented based on multi-stage MEMS optical switch units is illustrated, as shown in fig. 4 and 5, which is SxS optical cross-connect device, and the device includes an input fiber array, an input collimator array, a first multi-stage MEMS switch array (also referred to as a first-stage digital MEMS switch array), a lens, a second multi-stage MEMS switch array (also referred to as a second-stage digital MEMS switch array), an output collimator array, and an output fiber array.

The input end optical fiber array is used for coupling and inputting light beams and comprises S input ports, and the position layout of each port corresponds to the mapping position of the first multistage MEMS switch array one by one;

the input end collimator array comprises a plurality of micro lens units, the input end collimator array is used for collimating input light beams, each micro lens unit corresponds to an output port in a one-to-one mode, and the light beam collimating function is achieved by adjusting the distance between the collimator and the optical fiber array and the focal length of the micro lens. Wherein the collimator working distance is D1.

The first-stage digital MEMS switch array is positioned at the working distance of the collimating mirror. The included angle between the installation angle of the first multistage MEMS switch array and the input light beam is so that the light beams of the input and output switch arrays form an included angle of 2 to avoid light path interference. The first multi-stage MEMS switch array includes S switch units, each of which can select a specific angle to S directions. The switch units are arranged in a ring shape, the radius of the circle center is r, and the positions on the ring correspond to the rotating angle directions of the switch units one by one. Wherein the layout radius r satisfies the following formula one:

where f denotes the lens focal length.

In the optical relay system formed by the lens, the first-stage digital MEMS switch array and the second-stage digital MEMS switch array are respectively positioned at focal planes on two sides. The light spot conversion is realized by setting the focal length of the lens, and the beam waist radius of the light spot of the first-stage digital MEMS switch array is omega ₁ The beam waist radius of the light spot at the second stage of the digital MEMS switch array is omega ₂ ，ω ₁ And ω 2. The focal length satisfies the following formula two:

meanwhile, the lens can also realize the function of light path transformation, even if any micro-reflector on the first-stage digital MEMS switch array deflects in the same direction and angle, the light beam is mapped to the switch unit corresponding to the same position on the second-stage digital MEMS switch array.

The first stage digital MEMS switch array: comprises S switch units; each switching unit can switch the light beam to S (positive integer) directions, each direction being capable of switching a set angle; the S switch arrangement modes are determined by the switching directions and the switching angles of the switch units in the first optical array. The arrangement direction of the switch units corresponds to the switching direction of the first multistage MEMS switch array one by one; the distance between the switch unit and the central point and the switching angle of the first multi-stage MEMS switch array meet the first formula;

output end collimator array and output end fiber array: the S output beams are collimated, and are received from the second-stage digital MEMS switch array and are efficiently coupled out;

next, an SxT optical crossing device provided by the embodiment of the present application is introduced, the device includes an input fiber array, an input collimator array, a first stage digital MEMS switch array, a lens, a second stage digital MEMS switch array, an output collimator array, and an output fiber array.

The input end fiber array comprises a two-dimensional fiber array, and the input end collimator array comprises a two-dimensional collimator array. The method includes collimating S (positive integer) input beams, mapping beam waist positions to a first multi-stage MEMS optical switch unit, the first multi-stage MEMS switch array including S first multi-stage MEMS optical switch units.

A first multi-stage MEMS switch array: comprises S switch units; each switching unit can switch the light beam to M (positive integer) directions, each direction being capable of switching a set angle; the arrangement mode of the S switch units is determined by the switching direction and the switching angle of the switch units in the second multi-stage MEMS switch array. The arrangement direction of the switch units corresponds to the switching direction of the second multistage MEMS switch array one by one; the distance between the switch unit and the central point and the switching angle of the second multi-stage MEMS switch array meet the following formula III:

Di＝f*tan(αjπ/360)。

and α j is a deflection angle of the second multi-stage MEMS switch array along with the corresponding switch unit.

Lens: the focal length is f, and the formula II is satisfied; the first multi-stage MEMS switch array and the second multi-stage MEMS switch array are respectively positioned at the front, the back and the focal plane of the lens; the light spot conversion function is realized: mapping a beam waist on the first multi-stage MEMS switch array to a second multi-stage MEMS switch array; and (3) realizing light path conversion: enabling any micro-reflector on the first multi-stage MEMS switch array to deflect in the same direction and angle, and mapping the light beam to a switch unit corresponding to the same position on the second multi-stage MEMS switch array; the focal length satisfies the following formula four:

a second multi-stage MEMS switch array: comprises T switch units; each switching unit can switch the light beam to S (positive integer) directions, and each direction can switch at least one set angle; the arrangement mode of the T switch units is determined by the switching direction and the switching angle of the switch units in the first multi-stage MEMS switch array. The arrangement direction of the switch units corresponds to the switching direction of the first multistage MEMS switch array one by one; the distance between the switch unit and the central point and the switching angle of the first multi-stage MEMS switch array meet the formula five:

Dj＝f*tan(αiπ/360)，

and alpha i is the deflection angle of the first multi-stage MEMS switch array along with the corresponding switch unit.

Output end collimator array and output end optical fiber array: the T (positive integer) output beams are collimated, and the T beams from the second optical switch array are received and coupled out.

It should be noted that, for simplicity of description, the above-mentioned method embodiments are described as a series of acts or combination of acts, but those skilled in the art will recognize that the present application is not limited by the order of acts described, as some steps may occur in other orders or concurrently depending on the application. Further, those skilled in the art should also appreciate that the embodiments described in the specification are preferred embodiments and that the acts and modules referred to are not necessarily required in this application.

To facilitate better implementation of the above-described aspects of the embodiments of the present application, the following also provides relevant means for implementing the above-described aspects.

It should be noted that the above-described embodiments of the apparatus are merely schematic, where the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. In addition, in the drawings of the embodiments of the apparatus provided in the present application, the connection relationship between the modules indicates that there is a communication connection therebetween, which may be specifically implemented as one or more communication buses or signal lines. One of ordinary skill in the art can understand and implement it without inventive effort.

Through the above description of the embodiments, those skilled in the art will clearly understand that the present application can be implemented by software plus necessary general-purpose hardware, and certainly can also be implemented by special-purpose hardware including special-purpose integrated circuits, special-purpose CPUs, special-purpose memories, special-purpose components and the like. Generally, functions performed by computer programs can be easily implemented by corresponding hardware, and specific hardware structures for implementing the same functions may be various, such as analog circuits, digital circuits, or dedicated circuits. However, for the present application, the implementation of a software program is more preferable. In the above embodiments, the implementation may be wholly or partially realized by software, hardware, firmware, or any combination thereof.

Claims

1. A multi-level MEMS optical switch cell, comprising: a micro-mirror, a cantilever beam, N electrodes, and M stops, the N, M all being positive integers greater than or equal to 2, wherein,

the cantilever beam is used for enabling the micro-reflector to keep an initial state when no acting force is generated by the N electrodes; causing the micro-mirror to be in a target deflection state when at least one of the N electrodes generates a force; when the acting force is zero, the micro mirror is restored to the initial state;

at least one electrode in the N electrodes is used for generating acting force and controlling the micro mirror to enter a deflection state;

the micro-mirror is used for entering a deflection state under the action of at least one electrode in the N electrodes;

at least one blocker of the M blockers to block the micro-mirror such that the micro-mirror stops to a target deflection state.

2. The multi-stage MEMS optical switch cell of claim 1, wherein the cantilever beam is configured to maintain the micro-mirror in an initial state when no voltage is applied to the N electrodes; causing the micro-mirror to be in a target deflection state when at least one of the N electrodes generates an electrostatic force; when the electrostatic force is zero, restoring the micro mirror to the initial state;

at least one electrode in the N electrodes is used for generating electrostatic force to the micro-mirror after voltage is applied.

3. The multi-stage MEMS optical switch cell of claim 1, further comprising: n through-silicon-vias and an electrode control circuit, wherein,

the N electrodes are respectively connected with the electrode control circuit through the N silicon through holes;

the electrode control circuit is used for controlling at least one electrode in the N electrodes to generate acting force.

4. The multi-stage MEMS optical switch cell of claim 1 wherein N and M are equal, and there is a one-to-one correspondence between the N electrodes and the M blockers;

when the ith electrode generates acting force, the ith stopper provides a block for the micro-mirror, so that the micro-mirror stops at the target deflection state, and i is a positive integer less than or equal to N.

5. The multi-stage MEMS optical switch unit of claim 4, wherein when the substrate is a circular structure, the N electrodes are uniformly distributed around a central position of the circular structure, and an included angle between two adjacent electrodes of the N electrodes is equal to 360 °/N.

6. The multi-stage MEMS optical switch cell of claim 1, wherein the micro-mirror comprises: a circular mirror plate.

7. The multi-stage MEMS optical switch unit of claim 1, wherein the number of the cantilever beams is K, the K is a positive integer, and the K is less than the N;

the M is greater than the N.

8. An optical interleaving arrangement, comprising: a multi-stage MEMS switch array, the multi-stage MEMS switch array comprising: the multi-stage MEMS optical switch unit of any one of claims 1 to 7.

9. The optical crossbar device of claim 8 wherein the multi-stage MEMS switch array is specifically a first multi-stage MEMS switch array, or a second multi-stage MEMS switch array;

the optical cross-connect apparatus further comprises: an input end fiber array, an input end collimator array, a lens, an output end collimator array and an output end fiber array, wherein,

the first multi-stage MEMS switch array comprising S first multi-stage MEMS optical switch cells, the first multi-stage MEMS optical switch cells as claimed in any one of claims 1 to 7, the S being a positive integer; the first multi-stage MEMS switch array is used for mapping the light beams output by the input end collimator array to the second multi-stage MEMS switch array through the lens;

the second multi-stage MEMS switch array comprising T second multi-stage MEMS optical switch cells, the second multi-stage MEMS optical switch cells as claimed in any one of claims 1 to 7, the T being a positive integer; the second multi-stage MEMS switch array is used for outputting the light beams from the first multi-stage MEMS optical switch array to the output end collimator array;

the output end collimator array is used for collimating the light beams output from the second multistage MEMS switch array;

and the output end optical fiber array is used for coupling and outputting light beams.

10. The optical crossovers device of claim 9, wherein the input end fiber array comprises: the position layout of each input port corresponds to the mapping position of the first multistage MEMS optical switch unit one by one;

each first multistage MEMS optical switch unit can switch beams to T directions, and the arrangement mode of the first multistage MEMS optical switch units is determined by the switching direction and the switching angle of the second multistage MEMS optical switch unit and the focal length of a lens;

11. The optical interleaving device according to claim 10, wherein S is equal to T.

12. The optical crossbar device of claim 10 wherein the multi-stage MEMS optical switch cells are arranged in a ring on the multi-stage MEMS switch array.

13. The optical crossbar device of claim 12 wherein the switching of the optical beams takes a straight switching path, or a zigzag switching path, or an arc switching path when the current multi-stage MEMS optical switch cell in the multi-stage MEMS switch array is switched to the target multi-stage MEMS optical switch cell.

14. The optical interleaving device of claim 13, wherein the meander switched path comprises: a two-step linear switching path passing through a center point location of the multi-stage MEMS switch array.