Control method of MEMS optical switch

Abstract

To provide a control method of an MEMS optical switch suppressing the number of voltage parameters by simplifying voltage control even when controlling multi-channelization of a light emission port and across a four-quadrant area.SOLUTION: A control method of an MEMS optical switch includes an MEMS mirror and a light emission port comprised of a plurality of optical fibers, where a switching region of the MEMS mirror is defined as an angular space depending on an X axis, a Y axis, a + direction and a - direction, the angular space is projected on an end surface of the optical fibers of the light emission port to divide an arrangement region of the optical fibers into a first quadrant to a fourth quadrant, and a voltage that controls an angle of the MEMS mirror to a desired set angle is a control voltage. Further, an intersection of the X axis and the Y axis is set to 0 (V) in the control voltage of the MEMS mirror, and the end face of one optical fiber is made to correspond to the intersection. When the optical connection of the light reflected by the MEMS mirror is switched between the optical fibers, the switching between the + region and the - region of either or both of the X-axis and the Y-axis shall be performed via a setting of 0 (V).SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a method for controlling a MEMS optical switch. [Background technology]

[0002] Conventionally, MEMS (Micro Electro Mechanical Systems) having an oscillating part such as a mirror have been known.

[0003] One application of MEMS with mirrors is the MEMS optical switch. A MEMS optical switch has one or more light input ports and one or more light output ports. Furthermore, a movable mirror (MEMS mirror) equipped with a MEMS control mechanism is placed in the optical path between these light input and output ports, optically coupling the light input port and light output port.

[0004] In such MEMS optical switches, the tilt of the mirror is changed by supplying a control voltage to the MEMS through a control mechanism, changing the optical coupling between the light input port and the light output port and switching the light propagation path (see, for example, Figure 2 in Patent Document 1).

[0005] Furthermore, as a MEMS mirror to be mounted on the MEMS optical switch, for example, an electrostatic comb-type MEMS mirror that has comb-type electrodes and is driven by electrostatic attraction is disclosed in Patent Document 2. Patent Document 2 discloses a MEMS mirror that can be controlled around two axes, the X-X' axis and the Y-Y' axis.

[0006] By configuring the MEMS mirror to be controllable around two axes, the X-X' axis and the Y-Y' axis, as in the MEMS mirror described in Patent Document 2, the movable range of the MEMS mirror is expanded, and the number of multiple light input ports and light output ports can be increased.

[0007] For example, in the control method of an optical switch using a MEMS mirror shown in Figure 7 of Patent Document 1, two axes, the X axis and the Y axis, are set at the arrangement positions of multiple optical paths. Furthermore, by using the MEMS mirror of Patent Document 1 or the MEMS mirror of Patent Document 2, which can set a required angle across these two axes, it becomes possible to set a required angle on each of the X axis and the Y axis in the optical path (light output port) shown in Figure 7 of Patent Document 1 and to input light. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-219469 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-029849 Summary of the Invention [Problem to be solved by the invention]

[0009] According to the verification by the applicant and the inventor, even if the oscillation axis of the MEMS mirror is limited to only two directions, the +X axis and the +Y axis, where both the X axis and the Y axis are in the + (plus) direction, it has been confirmed that, for example, as shown in FIG. 16, if the number of light output ports of the MEMS optical switch is 100 or less, as shown in FIG. 16, oscillation with simple step voltage control is possible as shown in FIG. 17. In FIG. 16, one port is the light input port and the remaining 15 ports are the light output ports. In FIG. 17, the solid line represents the X-axis control voltage (X voltage) V(+X)(V) of the MEMS mirror, and the dashed line represents the Y-axis control voltage (Y voltage) V(+Y)(V) of the MEMS mirror. Furthermore, it has been confirmed that the number of control voltage parameters does not become enormous.

[0010] Note that Figure 16 shows an example of switching the optical connection state from the optical fiber arranged on the leftmost side of the optical fiber array on the bottom layer to the optical fiber arranged on the rightmost side of the optical fiber array on the top layer.

[0011] However, as the number of ports increases and the number of channels of the light output port increases, for example, as in the light output port 100 shown in Fig. 18, the layout area of ​​the end face of the optical fiber bundle that constitutes the light output port 100 expands fourfold. In this case, if the oscillation axes of the MEMS mirror are two axes, the +X axis and the +Y axis, as shown in Fig. 16, and the oscillation is only in the + direction, it is not possible to ensure a sufficient switching range of the MEMS mirror relative to the area of ​​the end face of the optical fiber bundle, and it becomes impossible to perform the switching operation of the MEMS mirror over the entire range of the optical fiber bundle.

[0012] Therefore, the applicant and the inventor of the present invention have defined the switching region of the MEMS mirror as an angular space spanned by two mutually orthogonal rotation axes (oscillation axes), the X-axis and the Y-axis, and rotation directions (oscillation directions), the + (plus) direction and the - (minus) direction. Projecting this angular space perpendicular to the optical axis of the light incident / exit port onto the end face of each fiber of the light incident / exit port results in, for example, the four quadrants of the light exit port 100 shown in Figure 18.

[0013] When rotating and oscillating the MEMS mirror in the + and - directions of the X or Y axis, switching to the + or - direction is possible by supplying each control voltage only to different electrodes (a + electrode that supplies a control voltage for rotation in the + direction, and a - electrode that supplies a control voltage for rotation in the - direction).

[0014] However, when the rotation axis (oscillation axis) direction of the MEMS mirror is set to any of the four directions of the +X axis, the +Y axis, the -X axis, and the -Y axis, it was found that the voltage control of the MEMS mirror frequently crosses multiple quadrants as the arrangement area expands, as shown in Figure 18, during the transition from the control voltage before switching the optical fiber to the control voltage after switching, as shown in Figure 19. In Figure 19, the two-dot chain line and solid line represent the X-axis control voltage (X voltage) V(-X)(V) and V(+X)(V), respectively, of the MEMS mirror, and the one-dot chain line and dashed line represent the Y-axis control voltage (Y voltage) V(-Y)(V) and V(+Y)(V), respectively, of the MEMS mirror.

[0015] The X voltage transitions to 0 (V) before the Y voltage, i.e., it rises after passing the Y axis. Next, the Y voltage transitions to 0 (V) with a time lag, i.e., it rises after passing the X axis.

[0016] Figure 18 shows an example of switching from the optical fiber arranged third from the left in the optical fiber array on the bottom layer in the third quadrant to the optical fiber arranged on the rightmost side in the optical fiber array on the top layer in the first quadrant, across the fourth quadrant.

[0017] Therefore, every time the quadrant changes during switching of the optical fiber, the sign of the MEMS mirror's oscillation axis also changes between + and -. The applicant and the present inventor have confirmed that this leads to a complication of voltage control supplied to the MEMS mirror and an increase in the number of voltage parameters. Furthermore, it has been confirmed that voltage control is required to switch the oscillation axis between + and - directions, and that since the four quadrant regions are each independent regions, voltage control for smooth optical response becomes difficult.

[0018] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a control method for a MEMS optical switch that simplifies voltage control even when multi-channeling the light output port and controlling across a four-quadrant region, and reduces the number of voltage parameters. [Means for solving the problem]

[0019] The above-mentioned problems are solved by the present invention as follows: That is, a control method of a MEMS optical switch of the present invention has a MEMS mirror and a light output port composed of a plurality of optical fibers, the switching region of the MEMS mirror is an angular space depending on two oscillation axes of X-axis and Y-axis which are orthogonal to each other and oscillation directions of + direction and - direction, the angular space is projected onto an end surface of the optical fiber constituting the light output port, and the arrangement region of the plurality of optical fibers is divided into four quadrants, first to fourth quadrants, in which the X-axis and Y-axis are divided into + region and - region, and a signal supplied to the MEMS mirror is supplied to the MEMS mirror to change the angle of the MEMS mirror to a desired setting angle. The voltage controlled at each point is the control voltage, and the intersection of the X and Y axes is set to 0 (V) in terms of the control voltage of the MEMS mirror. Furthermore, the end face of one of the optical fibers at the light output port is made to correspond to the intersection. When the optical connection of the light reflected by the MEMS mirror is switched between optical fibers by swinging the MEMS mirror, in the direction of the axis where the sign of the region changes when switching between the + region and the - region on either or both of the X and Y axes, the light is made to enter the optical fiber at the light output port located in each region of the four quadrants via a setting of 0 (V). [Effects of the Invention]

[0020] The control method for the MEMS optical switch of the present invention simplifies the control of the voltage supplied to the MEMS mirror and reduces the number of voltage parameters, making it possible to easily control the voltage even when the light output port has multiple channels and the control spans four quadrants.

[0021] Furthermore, even if the number of channels is increased, the number of voltage parameters can be stored in a memory mounted on the drive substrate of the MEMS optical switch, due to the reduction or suppression of the number of voltage parameters. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a plan view schematically showing an example of a structure of a MEMS used in a control method of a MEMS optical switch according to an embodiment of the present invention. [Figure 2]2 is an explanatory diagram showing an optical connection state between a light input / output port constituting the MEMS optical switch of the present invention and the MEMS of FIG. 1. FIG. [Figure 3] 3 is an explanatory diagram showing the state of the optical path of light incident on and reflected from the electrostatic comb-type MEMS of FIG. 2. FIG. [Figure 4] 1A to 1C are explanatory diagrams showing the arrangement of end faces of a plurality of optical fibers that constitute an optical input / output port according to an embodiment of the present invention, and the switching of optical connection states. [Figure 5] FIG. 5 is an explanatory diagram showing a modified embodiment of FIG. 4. [Figure 6] FIG. 5 is an explanatory diagram showing a further modification of FIG. 4. [Figure 7] 5 is a graph of voltage value versus supply time showing the supply state of the control voltage supplied to the MEMS of FIG. 1 in order to perform the switching of FIG. 4. [Figure 8] In FIG. 7, this is a graph of the voltage value vs. supply time when the control voltages V2(-X)(V), V2(+X)(V), V2(-Y)(V), and V2(+Y)(V) are set. [Figure 9] 6 is a graph showing an example of a supply state of a control voltage supplied to the MEMS of FIG. 1 in order to perform the switching of FIG. 5; [Figure 10] In Figure 9, this is a graph of voltage value vs. supply time when control voltages V2(+X)(V) and V2(-X)(V) are set to the X-axis control voltages V1(+X)(V) and V1(-X)(V). [Figure 11] In FIG. 9, this is a graph of voltage value vs. supply time when the Y-axis control voltage V1(+Y)(V) is set to 0(V). [Figure 12] In Figure 11, this is a graph of voltage value vs. supply time when control voltages V2(+X)(V), V2(-X)(V), and V2(+Y)(V) are set for the X-axis control voltages V1(+X)(V) and V1(-X)(V), and the Y-axis control voltage V1(+Y)(V). [Figure 13] This is a graph of voltage value vs. supply time when the time interval T0 in FIG. 8 is set to a minimum. [Figure 14]10 is a graph showing the voltage value versus supply time, illustrating the supply state of the control voltage supplied to the MEMS in the embodiment of the present invention. [Figure 15] 10 is a graph showing the relationship between the optical output from the light output port and the elapsed time in the MEMS optical switch according to the embodiment of the present invention. [Figure 16] 1A and 1B are explanatory diagrams showing 15 light output ports and switching of optical connection states in a conventional MEMS optical switch. [Figure 17] 17 is a graph of voltage value versus supply time showing the supply state of a control voltage supplied to a conventional MEMS mirror in order to perform the switching of FIG. 16. [Figure 18] 1A and 1B are explanatory diagrams showing multi-channel light output ports and switching of optical connection states in a conventional MEMS optical switch. [Figure 19] 19 is a graph showing the voltage value vs. supply time indicating the supply state of the control voltage supplied to the conventional MEMS mirror in order to perform the switching of FIG. 18. DETAILED DESCRIPTION OF THE INVENTION

[0023] The first feature of this embodiment is that it has a MEMS mirror and a light output port made up of a plurality of optical fibers, and the switching region of the MEMS mirror is an angular space depending on two oscillation axes of the X-axis and Y-axis which are orthogonal to each other and the oscillation directions of the + direction and the - direction, and the angular space is projected onto the end face of the optical fiber which makes up the light output port, and is divided into four quadrants, first to fourth quadrants, in which the X-axis and the Y-axis are respectively divided into + regions and - regions, and the voltage supplied to the MEMS mirror to control the angle of the MEMS mirror to a desired set angle is used as the control voltage, and the X-axis The intersection of the X and Y axes is set to 0 (V) in terms of the control voltage of the MEMS mirror, and the end face of one of the optical fibers at the light output port is made to correspond to the intersection. When the optical connection of the light reflected by the MEMS mirror is switched between optical fibers by swinging the MEMS mirror, in switching between the + and - regions on either or both the X and Y axes, the direction of the axis where the sign of the region changes is set to 0 (V), and light is input to the optical fiber at the light output port located in each of the four quadrants.

[0024] This method simplifies the control of the voltage supplied to the MEMS mirror and reduces the number of voltage parameters, making it possible to easily control the voltage even when the light output port has multiple channels and the control spans four quadrants.

[0025] Furthermore, even if the number of channels is increased, the number of voltage parameters can be stored in a memory mounted on the drive substrate of the MEMS optical switch, due to the reduction or suppression of the number of voltage parameters.

[0026] The second feature of this embodiment is that it is a control method for a MEMS optical switch that, when switching between the + region and the - region, passes through the 0 (V) setting in both the X-axis and Y-axis directions.

[0027] In addition to the above-mentioned effects, this method makes it possible to more easily control the voltage of the MEMS mirror.

[0028] Furthermore, since 0 (V) passes through in both the X-axis and Y-axis directions of the oscillation axes of the MEMS mirror, the angle of the MEMS mirror can be set at the intersection point 0 more accurately and reliably.

[0029] Furthermore, since the setting of 0 (V) is passed through in both the X-axis and Y-axis directions, if the total number of optical fibers at the optical input / output ports is a × a, the number of voltage parameters is (a × a) 2 The reason for this is that even if the light output port is the farthest from the intersection point 0, it goes through the setting of 0 (V), so there is a transition from a to 0 and from 0 to a, and as a result the number of voltage parameters is at most 2 × (a × a).

[0030] A third feature of this embodiment is that the control voltage supplied to the MEMS mirror before switching the optical connection of the optical fiber is V1a(V), and the control voltage supplied to the MEMS mirror to switch the optical connection to the desired optical fiber is V1b(V), and a voltage V2(V) that is less than V1a(V) or less than V1b(V) and greater than 0(V) is supplied to the MEMS mirror during at least one of the transitions from V1a(V) to 0(V) or from 0(V) to V1b(V).

[0031] In addition to the above effects, this method makes it possible to suppress or prevent resonance of the oscillating part of the MEMS mirror by supplying V2(V) as a control voltage, thereby suppressing or preventing ringing in the light emission to the optical fiber that constitutes the light emission port, and shortening the optical response time.

[0032] Furthermore, since the ringing is suppressed or prevented, the switching time between a plurality of optical fibers at the light output port is shortened, enabling faster switching operations.

[0033] The fourth feature of this embodiment is that it is a control method for a MEMS optical switch that supplies V2(V) to the MEMS mirror during either the transition from V1a(V) to 0(V) or the transition from 0(V) to V1b(V).

[0034] In addition to the above-mentioned effects, this method can suppress or eliminate the occurrence of resonance in both the X-axis and Y-axis of the oscillation portion of the MEMS mirror.

[0035] A fifth feature of this embodiment is that it is a control method for a MEMS optical switch in which V2(V) is one voltage value.

[0036] In addition to the above-mentioned effects, this method makes it possible to simplify the control of the voltage supplied to the MEMS mirror, reduce the number of voltage parameters, and easily control the voltage.

[0037] A sixth feature of this embodiment is that the oscillation axes of the MEMS mirror are two X- and Y-axes that are orthogonal to each other at 90°, and the method for controlling a MEMS optical switch is such that the X- and Y-axes that are the oscillation axes of the MEMS mirror coincide with the directions of the X- and Y-axes that define the arrangement area of ​​the light output port.

[0038] In addition to the above-mentioned effects, this method allows the most accurate alignment of the direction of the swing angle of the MEMS mirror with the arrangement direction of the optical fibers at the light output port.

[0039] Hereinafter, a method for controlling a MEMS optical switch according to an embodiment of the present invention will be described with reference to FIGS.

[0040] The MEMS optical switch according to this embodiment, which is an object to be controlled, has a MEMS mirror and a plurality of light output ports, and further has a light input port in this embodiment.

[0041] The MEMS mirror has at least two support parts and two oscillating parts supported by the support parts. As a specific structure, as shown in Figure 1, one example is a configuration in which the central axes of two support parts 3a and 3b are perpendicular to each other and the mirror is made up of an electrostatic comb-type MEMS1 (hereinafter referred to as MEMS1) equipped with comb-type electrodes and driven by electrostatic attractive force.

[0042] A control voltage is supplied from a MEMS control device (not shown) to a MEMS 1 such as that shown in FIG. 1. The supply of the control voltage causes the oscillating portion 2a of the MEMS 1 to oscillate around the X-axis, with the support portion 3a as its central axis. Furthermore, the oscillating portion 2b oscillates around the Y-axis, with the support portion 3b as its central axis. That is, the control voltages supplied from the MEMS control device to the MEMS 1 include an X-axis control voltage (X voltage) and a Y-axis control voltage (Y voltage). The oscillation angles around the X-axis and Y-axis generated in the oscillating portions 2a and 2b, as well as the desired set angles, are controlled by these control voltages.

[0043] The MEMS control device can be configured using a voltage output device, etc., and when rotating and oscillating the MEMS mirror in the + (plus) or - (minus) direction of the X or Y axis according to a switching schedule, switching operation in the + or - direction is possible by supplying each control voltage only to different electrodes (a + electrode that supplies a control voltage for rotation in the + direction of the X or Y axis, and a - electrode that similarly supplies a control voltage for rotation in the - direction of the X or Y axis).

[0044] The support portion 3a extends in the X-axis direction, connects the oscillating portions 2a and 2b, and supports the support portion 3a so that it can oscillate around the X-axis. The oscillating portion 2b is provided on the outer periphery of the oscillating portion 2a and is formed so as to surround the oscillating portion 2a. Furthermore, the support portion 3b extends in the Y-axis direction, connects the oscillating portion 2b to the outer fixed frame portion 4, and supports the support portion 3b so that it can oscillate around the Y-axis. Therefore, the oscillating portion 2a is supported by the support portion 3b so that it can oscillate together with the oscillating portion 2b around the Y-axis. Therefore, the oscillating portion 2a can oscillate around two axes: the X-axis and the orthogonal Y-axis. This oscillating portion 2a is configured as a mirror, and the MEMS 1 is configured as a MEMS mirror.

[0045] When the oscillating portion 2a is a mirror, the surface of the oscillating portion 2a may be mirror-finished or coated with a metal film such as gold or aluminum by vapor deposition or the like.

[0046] When a control voltage is supplied between the outer comb teeth 2a1 and the inner comb teeth 2b1 around the X axis from the MEMS control device, a torque around the X axis is generated in the outer comb teeth 2a1 around the X axis, that is, in the oscillation portion 2a.

[0047] When a control voltage is supplied between the outer comb teeth 2b2 and the inner comb teeth 4a around the Y axis, torque around the Y axis is generated in the outer comb teeth 2b2 around the Y axis, i.e., in the inner movable frame body (i.e., the oscillating part 2b) integrally connected to the oscillating part 2a. Therefore, the oscillating part 2a can oscillate around two axes, the X axis and the orthogonal Y axis.

[0048] The MEMS1 is formed from at least two silicon wafer layers, each made of n-type or p-type doped conductive silicon. Furthermore, a silicon oxide layer is formed between the two silicon wafer layers as an electrical insulating layer, and the two silicon wafer layers are bonded together via this silicon oxide. The aforementioned components of the MEMS1 are integrally formed on each silicon wafer layer, and each layer is electrically equipotential. Alternatively, a silicon-on-insulator (SOI) wafer, in which the two silicon wafer layers and the insulating layer are already integrated, may be used.

[0049] The MEMS 1 of this embodiment can be modified in various ways, and may be a flat electrode type MEMS in which the central axes of two support parts are perpendicular to each other and are controlled by electrostatic attraction.

[0050] Next, the light input port and the light output port will be described. The light input port and the light output port are each composed of an optical fiber. Furthermore, as shown in FIG. 2, the light output port 6 is composed of a plurality of optical fibers. The MEMS optical switch according to the present invention is composed of an n×m optical switch, in which the number n of optical fibers in the light input port is 1 or more (n≧1), and the number m of optical fibers in the light output port 6 is also 1 or more (m≧1). Note that in this embodiment, as shown in FIG. 2, a 1×15 optical switch is schematically illustrated, in which n is 1 and m is 15, but the number of light input and output ports can each be set to any number equal to or greater than 1.

[0051] 4 to 6, as an example, a multi-channel configuration is assumed in which n is 1 and m is 63 optical output ports 6. The optical fiber 5a constituting the optical input port 5 is only one optical fiber at the left end of the top layer 6h, and the other 63 optical fibers are optical output ports 6. Therefore, there are seven optical fibers constituting the optical output ports only in the top layer 6h.

[0052] 2, the light input port 5 is an input port for light to the MEMS 1, and is optically coupled to a light source (not shown) via a lens 7, so that light propagating from the light source through an optical fiber 5a enters the MEMS 1. The light source is a light source that emits visible light of 400 nm or more and 700 nm or less, infrared light, ultraviolet light, etc., and may be a semiconductor laser LD (Laser Diode), a light emitting diode (LED), etc.

[0053] On the other hand, the output port of the light reflected by the MEMS mirror made up of MEMS 1 is the light output port 6. Light incident from the light input port 5 is reflected by the MEMS mirror, and passes through the lens 7 to be input to a desired optical fiber among the multiple optical fibers that make up the light output port 6. The light then propagates through that optical fiber and is output to the outside.

[0054] The set angle of the mirror of the MEMS 1 and the end position of each optical fiber that constitutes the light output port 6 are arranged and set in advance in correspondence with each other. By changing the set angle and controlling the orientation of the mirror, light propagated from the light input port 5 is reflected and propagated to one of the optical fibers that constitute the light output port 6. One of the optical fibers that becomes the propagation destination within the light output port 6 is optically coupled to the light input port 5.

[0055] In this embodiment, the optical fiber constituting the light output port 6 is configured by stacking an optical fiber array made up of a plurality of optical fibers, and the core axes of the optical fibers are arranged in parallel to each other.

[0056] As shown in Figures 4 to 6, a plurality of the optical fiber arrays are stacked and arranged in multiple stages (eight stages in the embodiment of Figures 4 to 6) in the vertical direction in the figures to form the light output port 6. Note that the number of optical fibers constituting the light output port 6 differs between Figure 2 and Figures 4 to 6. This is because Figure 2 omits the number of optical fibers in the light output port 6 in order to prioritize ease of viewing the optical connection state between the light input / output ports (5, 6) and the MEMS 1. However, the configuration of the light output port 6 in an actual embodiment is a multi-channel structure with m=63 optical fibers, as shown in Figures 4 to 6.

[0057] 4 to 6, in this embodiment, each optical fiber array (6a to 6h) is configured by arranging a plurality of optical fibers (8 fibers) in a line parallel to the X axis in each stage. Furthermore, each optical fiber array (6a to 6h) is stacked in the vertical direction parallel to the Y axis, so that the core center points are arranged in a square lattice pattern in which they are linearly aligned in the directions of the X axis and the Y axis.

[0058] Each optical fiber constituting the optical input / output ports (5, 6) is, for example, a single-mode optical fiber made of quartz, with a core (not shown) surrounded by a cladding having a refractive index lower than that of the core. Furthermore, a predetermined amount of the coating is stripped from the end of each optical fiber, exposing the bare optical fiber.

[0059] In order to increase the number of ports (number of optical fibers) of the light output port 6, the cladding diameter of the optical fiber that constitutes the light output port 6 may be thinned by etching.

[0060] Furthermore, all of the optical fibers that make up the light input / output ports (5, 6) may be collected into one bundle fiber.

[0061] The optical fibers constituting the light input / output ports (5, 6) are not limited to single-mode optical fibers made of quartz, but plastic optical fibers, multi-mode optical fibers made of quartz, etc. may also be used.

[0062] Furthermore, the switching region of the MEMS mirror is defined as an angular space spanned by two mutually orthogonal rotation axes (oscillation axes), the X-axis and the Y-axis, and two rotation directions (oscillation directions), the positive and negative directions. By dividing the X-axis and the Y-axis into positive and negative regions in this way, the set region in which the MEMS1 mirror can oscillate is divided into four quadrants, from the first quadrant to the fourth quadrant. Furthermore, the result of projecting this angular space perpendicular to the optical axis of the light incident / exit ports (5, 6) onto the end faces of each fiber of the light incident / exit ports (5, 6) is the four quadrants at the light incident / exit ports (5, 6) shown in, for example, Figures 4 to 6.

[0063] 1, the X-axis and Y-axis, which are the oscillation axes of the MEMS 1, are perpendicular to each other at 90°. Furthermore, it is preferable to set the axial directions of the X-axis and Y-axis, which are the two oscillation axes of the MEMS 1, and the X-axis and Y-axis of the light output port 6 to coincide with each other and with each other, respectively, and to set them as common axes. This is because this allows the most accurate alignment of the direction of the oscillation angle of the MEMS mirror (MEMS 1) with the arrangement direction of each optical fiber of the light output port 6.

[0064] The optical fibers constituting the light incident / output ports (5, 6) and the MEMS 1 are arranged face-to-face as shown in Fig. 2. The surface of the MEMS 1 shown in Fig. 1 and the end faces of the light incident / output ports (5, 6) shown in Figs. 4 to 6 are arranged face-to-face. Therefore, the + and - directions of the X axis of the MEMS 1 shown in Fig. 1 are opposite to the + and - directions of the X axis of the light incident / output ports (5, 6) shown in Figs. 4 to 6.

[0065] The four quadrants of the light input / output ports (5, 6) are defined as follows: As shown in Figures 4 to 6, the quadrant consisting of the +X-axis region and the +Y-axis region is the first quadrant (the upper right region in Figures 4 to 6), the quadrant consisting of the -X-axis region and the +Y-axis region is the second quadrant (the upper left region in Figures 4 to 6), the quadrant consisting of the -X-axis region and the -Y-axis region is the third quadrant (the lower left region in Figures 4 to 6), and the quadrant consisting of the +X-axis region and the -Y-axis region is the fourth quadrant (the lower right region in Figures 4 to 6).

[0066] Therefore, the arrangement area of ​​the multiple optical fibers that make up the light output port 6 is set in two axial directions, ±X-axis and ±Y-axis, which are orthogonal to each other at 90°, as shown in Figures 4 to 6. Furthermore, the X-axis and Y-axis are set in common across the arrangement positions of all of the optical fibers that make up the light output port 6.

[0067] In the MEMS 1 of FIG. 1, when a control voltage is applied to the + electrode on the X axis and the voltage value is increased, the mirror moves away from intersection 0 on the +X axis of the optical fiber end face of the light incident / emitting port (5, 6). That is, the oscillation (rotation) direction of the mirror oscillates in the direction in which the + value on the X axis of the light incident / emitting port (5, 6) increases. Similarly, when a control voltage is applied to the - electrode on the X axis or the + electrode or - electrode on the Y axis and the voltage value is increased, the mirror moves away from intersection 0 on the -X axis, +Y axis, or -Y axis of the optical fiber end face of the light incident / emitting port (5, 6). That is, the oscillation (rotation) direction of the mirror oscillates in the direction in which the - value on the X axis of the light incident / emitting port (5, 6) increases, or in the direction in which the + or - value on the Y axis increases.

[0068] Furthermore, the end face of one optical fiber of the light output port 6 is made to correspond to the intersection 0 of the X-axis and Y-axis set at the light output port 6. As shown in FIGS. 4 to 6, an optical fiber array 6d near the middle in the stacking direction is selected as the optical fiber to be made to correspond to intersection 0. Furthermore, if the optical fiber array 6d is composed of an odd number of optical fibers, intersection 0 is made to coincide with the end face of the optical fiber arranged in the middle. If the optical fiber array 6d near the middle is composed of an even number (8) of optical fibers as shown in FIGS. 4 to 6, intersection 0 is made to coincide with the end face of the optical fiber arranged on either the left or the fifth optical fiber from the right near the center.

[0069] Furthermore, the intersection point 0 is set to 0 (V) in terms of the control voltage of the MEMS mirror (MEMS1). That is, when the control voltage is set to 0 (V), the intersection point 0 is aligned with the optical fiber end face of the light output port 6 where the light is reflected and incident, at the set angle of the MEMS mirror.

[0070] Next, we will explain the method of supplying a control voltage to the MEMS 1 and the switching operation of the optical fiber at the light output port 6 in the control method for the MEMS optical switch of the present invention. Light propagates through the optical fiber 5a at the light input port 5 and is output from the end face of the optical fiber 5a, and is reflected by the MEMS mirror swung to a desired angle by control voltages on the X and / or Y axes, and the reflected light is made incident on a desired optical fiber at the light output port 6. In other words, light is made incident on a desired optical fiber among the optical fibers at the light output port 6 arranged in each of the four quadrants.

[0071] As shown in Figure 3, the unit of switching operation of the mirror of MEMS 1 is 2 x θ (rad), where θ is the angle of incidence of incident light 8a from light input port 5 and the angle of reflection of reflected light 8b by the mirror. Note that the reference number 9 is the normal to the mirror's reflecting surface. The unit of the arrangement area of ​​the optical fiber at the light input / output ports (5, 6) is (μm).

[0072] The angle of the MEMS mirror oscillates and switches in response to the control voltage, and so does the optical fiber that is optically connected to the light output port 6. The control voltage supplied to the MEMS 1 before switching the optical connection of the optical fiber is defined as V1a(V), and the control voltage supplied to the MEMS 1 to switch the optical connection to the desired optical fiber is defined as V1b(V).

[0073] That is, V1a(V) is a control voltage for setting the angle of the MEMS mirror so that it is optically connected to the optical fiber before switching. The control voltage transitions from the supply state of V1a(V) to V1b(V).

[0074] In a more preferred embodiment of the present invention, the control voltage does not transition directly from V1a (V) to V1b (V), but passes through a voltage supply state where the control voltage is set to 0 (V) midway through the transition. That is, a feature of the present invention is a control method for a MEMS optical switch that switches to the desired optical fiber to which the optical connection is originally intended to be switched, via a switching state to the optical fiber at or near the center that coincides with the intersection 0.

[0075] Furthermore, there are cases where the layout area of ​​the optical fiber before switching and the layout area of ​​the optical fiber after switching switch between + and - areas (changes the sign of the area) in either or both of the X and Y axes. For example, in Figure 4, when comparing the layout area of ​​the optical fiber before switching and the layout area of ​​the optical fiber after switching, the signs of the areas change from - areas to + areas on both the X and Y axes. Also, in Figure 5, when comparing the layout area of ​​the optical fiber before switching and the layout area of ​​the optical fiber after switching, the Y axis remains in the + area, but the sign of the area changes from + area to - area on the X axis. Furthermore, in Figure 6, when comparing the layout area of ​​the optical fiber before switching and the layout area of ​​the optical fiber after switching, the Y axis remains in the - area, but the sign of the area changes from + area to - area on the X axis.

[0076] In this way, when the sign of the optical fiber placement area of ​​the light output port 6 changes before and after switching, the control voltage must pass through a voltage supply state where it is 0 (V) in the axial direction where the sign changes, and the switching operation to the optical fiber end face placed at intersection 0 must be performed. Note that in the axial direction where the sign of the optical fiber placement area does not change, it is not necessary to pass through 0 (V). In the case of Figure 4, the setting of 0 (V) is used before and after switching the optical fiber on both the X and Y axes. In the cases of Figures 5 and 6, the setting of 0 (V) is used before and after switching the optical fiber on the X axis, but it is not necessary to use the setting of 0 (V) on the Y axis.

[0077] Setting via 0(V) means that, as shown in any of Figures 7 to 12, the control voltage supplied to MEMS1 is first set from V1a(V) to 0(V), and then the control voltage value is increased from 0(V) to the control voltage V1b(V) that results in the desired MEMS mirror switching angle.

[0078] Figures 7 and 8 are graphs of voltage value versus supply time showing one of the supply states of the control voltage supplied to the MEMS 1 to perform the switching operation between the optical fibers of the light output port 6 shown in Figure 4. Figures 9 to 12 are graphs of voltage value versus supply time showing one of the supply states of the control voltage supplied to the MEMS 1 to perform the switching operation between the optical fibers of the light output port 6 shown in Figure 5.

[0079] 7 to 12, the set time of 0 (V) is a time interval T0 (seconds). An example of T0 is a set time of 20 μsec to 3 ms.

[0080] In Figures 7 and 8, V1a(V) corresponds to V1(-X)(V) and V1(-Y)(V), respectively. Furthermore, V1b(V) corresponds to V1(+X)(V) and V1(+Y)(V), respectively. In Figures 9 to 12, V1a(V) corresponds to V1(+X)(V) and V1(+Y)(V), respectively. Furthermore, V1b(V) corresponds to V1(-X)(V) and V1(+Y)(V), respectively. Hereinafter, as needed for explanation, in Figures 7 and 8, V1(-X)(V) and V1(-Y)(V) will be collectively referred to as V1a(V), and V1(+X)(V) and V1(+Y)(V) will be collectively referred to as V1b(V). 9 to 12, V1(+X)(V) and V1(+Y)(V) are collectively represented as V1a(V), and V1(-X)(V) and V1(+Y)(V) are collectively represented as V1b(V).

[0081] 4, the light output destination is switched from the optical fiber arranged second from the left in the optical fiber array 6c in the third layer from the bottom in the third quadrant, via the optical fiber arranged at intersection 0, to the optical fiber arranged at the rightmost position in the optical fiber array 6g in the second layer from the top in the first quadrant. In order to perform such a switching operation between the optical fibers of the light output port 6, a control voltage is supplied to the MEMS 1 in the state shown in either FIG. 7 or FIG. 8.

[0082] 7 or 8, the angle of the MEMS mirror is swung and set so that, by supplying the X-axis control voltage V1(-X)(V) and the Y-axis control voltage V1(-Y)(V), the MEMS mirror is optically connected to the optical fiber arranged second from the left in the optical fiber array 6c in the third quadrant shown in Fig. 4. This is the state before the optical connection of the optical fiber at the light output port 6 is switched.

[0083] From this state, in order to switch the optical connection of the desired optical fiber to the optical fiber arranged at the rightmost position of the optical fiber array 6g in the first quadrant, V1(-X)(V) is transitioned to the X-axis control voltage V1(+X)(V), and V1(-Y)(V) is transitioned to the Y-axis control voltage V1(+Y)(V). During this transition, in both Figures 7 and 8, the voltage supply state is set to the arrangement position of the optical fiber at intersection 0, that is, a control voltage of 0(V).

[0084] 5, the light emission destination is switched from the optical fiber arranged second from the right in the optical fiber array 6f in the third layer from the top in the first quadrant to the optical fiber arranged on the leftmost side in the optical fiber array 6f in the second quadrant, via the optical fiber arranged at intersection 0. In order to perform such a switching operation between the optical fibers of the light emission port 6, a control voltage is supplied to the MEMS 1 in any of the states shown in FIGS.

[0085] 9 to 12, by supplying the X-axis control voltage V1(+X)(V) and the Y-axis control voltage V1(+Y)(V), the angle of the MEMS mirror is swung and set so that it is optically connected to the optical fiber arranged second from the right in the optical fiber array 6f in the first quadrant shown in Fig. 5. This is the state before the optical connection of the optical fiber at the light output port 6 is switched.

[0086] From this state, in order to switch the optical connection of the desired optical fiber to the leftmost optical fiber of the optical fiber array 6f in the second quadrant, the V1(+X)(V) is transitioned to the X-axis control voltage V1(-X)(V). Meanwhile, the V1(+Y)(V) remains V1(+Y)(V) even after the transition. During this transition, the X-axis control voltage passes through a voltage supply state set to the arrangement position of the optical fiber at intersection 0, i.e., a control voltage of 0(V), as shown in FIGS. 9 to 12. Meanwhile, the Y-axis control voltage remains unchanged at V1(+Y)(V) before and after the transition, so it does not necessarily have to pass through the 0(V) setting as shown in FIG. 9 or 10, or it may pass through the 0(V) setting as shown in FIG. 11 or 12.

[0087] In FIGS. 4 to 6, a different control voltage value is supplied to each optical fiber constituting the light output port 6. Therefore, the control voltage value supplied differs for each optical fiber to be switched. Therefore, the voltage value must be changed in the program for the supplied control voltage. However, by determining the arrangement positions of the optical fiber end faces in a square lattice pattern without any deviation, V1(+Y)(V) can be replaced with V1(-Y)(V) in FIGS. 9 to 12, and the switching operation between the optical fibers of the light output port 6 shown in FIG. 6 can be performed. That is, the light output destination is switched from the optical fiber arranged second from the right in the optical fiber array 6b in the second layer from the bottom in the fourth quadrant, via the optical fiber arranged at intersection 0, to the optical fiber arranged on the leftmost side in the optical fiber array 6b in the third quadrant.

[0088] According to the control method of the MEMS optical switch described above, when switching between the + and - regions of the arrangement region of the optical fiber that constitutes the light output port 6, the control voltage of MEMS1 (MEMS mirror) is set to 0 (V) in the axial direction where the sign of the region changes. Therefore, even if the sign of the region changes, it is possible to simplify the voltage control to only two patterns of operation: a transition operation of the control voltage from V1a (V) to 0 (V), and a transition operation from 0 (V) to V1b (V). In other words, the switching operation of the optical fiber that accompanies the transition operation is prevented from crossing over into a quadrant other than the quadrant where the optical fiber is located before the optical connection is switched and the quadrant where the optical fiber is located after the optical connection is switched.

[0089] Therefore, the change in the sign of the MEMS mirror's oscillation axis (+ / -) during the transition from V1a (V) to V1b (V) is also suppressed, which simplifies the control of the voltage supplied to the MEMS mirror (MEMS1) and reduces the number of voltage parameters. This makes it possible to easily control the voltage even when the light output port 6 is multi-channel and controlled across four quadrants.

[0090] Furthermore, even if the number of channels is increased, the number of voltage parameters can be stored in a memory mounted on the drive substrate of the MEMS optical switch, due to the reduction or suppression of the number of voltage parameters.

[0091] Furthermore, when switching between the positive and negative regions of the X and Y axes occurs in the optical fiber arrangement region of the light output port 6, it is more preferable to set the control voltage to 0 (V) in both the X and Y directions. That is, as shown in Figures 7 and 8 or 11 and 12, the control voltage supplied to the MEMS 1 is always set to 0 (V) once during the transition from V1a (V) to V1b (V).

[0092] The reason for this is that the overlap of the supply operations of each control voltage (X-axis control voltage and Y-axis control voltage) between the + and - regions of the optical fiber arrangement region of the light output port 6 is resolved by supplying 0 (V). In Figures 7 to 12, except for Figures 9 and 10, both the X-axis control voltage and the Y-axis control voltage are set to 0 (V), and it can be seen that the overlap is resolved over the time interval T0.

[0093] Since the overlap is eliminated, the increase in the number of voltage parameters in the time interval T0 is also eliminated, and therefore the voltage control of the MEMS mirror (MEMS1) can be performed more easily.

[0094] Furthermore, since 0 (V) passes through in both the X-axis and Y-axis directions of the oscillation axes of the MEMS mirror, the angle of the MEMS mirror can be set at the intersection point 0 more accurately and reliably.

[0095] Furthermore, since both the X-axis and Y-axis directions are set to 0 (V), if the total number of optical fibers at the optical input / output ports (5, 6) is a × a, the number of voltage parameters is (a × a) 2The maximum number of voltage parameters is 2 × (a × a). This is because even if the light output port is the farthest from the intersection 0, it passes through the setting of 0 (V), resulting in a transition from a to 0 and from 0 to a, and as a result the maximum number of voltage parameters is 2 × (a × a). In the case of the light input / output ports (5, 6) in Figures 4 to 6, the total number of optical fibers is 8 × 8, or 64. However, the number of voltage parameters is (8 × 8) 2 =64 2 = 4096, but can be reduced to 2 × (8 × 8) = 2 × 64 = 128.

[0096] Furthermore, it is more preferable to supply a control voltage V2(V) to the MEMS1 during at least one of the transitions from V1a(V) to 0(V) or from 0(V) to V1b(V), as shown in Figures 8, 10, and 12. For ease of explanation, V2(+X), V2(-X), V2(+Y), and V2(-Y) in Figures 8, 10, and 12 will be collectively referred to as V2(V).

[0097] The voltage value of V2(V) is set to be less than V1a(V) or less than V1b(V) and greater than 0(V). Furthermore, the voltage value of V2(V) is a voltage value at which the maximum swing amplitude of the oscillating unit 2a becomes equal to a desired set angle, which will be described later, when V2(V) is supplied to the oscillating unit 2a. The desired set angle is the set angle of the oscillating unit 2a when either 0(V) or V1b(V) is supplied to the MEMS 1.

[0098] For example, when going from V1a(V) through 0(V), the next voltage value to transition from the V1a supply state is 0(V). When 0(V) is supplied, the swinging part 2a swings, and the set angle at which the optical fiber is optically connected to the end face of the optical fiber located at the intersection 0 becomes the desired set angle.

[0099] Furthermore, when the transition occurs to V1b(V) after passing through 0(V), the oscillating part 2a oscillates when V1b(V) is supplied, and the set angle at which the optical fiber is optically connected to the end face of a desired optical fiber among the multiple optical fibers at the light output port 6 becomes the desired set angle.

[0100] When V2 (V) is supplied, the voltage after transition (0 (V) or V1b (V)) is supplied to the MEMS 1 at the time (timing) when the oscillating part 2a oscillates to the desired set angle.

[0101] By supplying V2(V) as the control voltage in this manner, it is possible to suppress or prevent resonance at the set angle that occurs when the oscillating unit 2a transitions directly from a V1a(V) supply state to a V1b(V) supply state. That is, because the supply of V2(V) causes the oscillating unit 2a to swing to the set angle, when the next transition to the V1b(V) supply state causes the oscillating unit 2a to swing to the set angle, it can directly transition to swing to the set angle. Therefore, resonance of the oscillating unit 2a can be suppressed or prevented, and ringing in the light emission to the optical fiber that constitutes the light emission port 6 is suppressed or prevented, thereby shortening the optical response time.

[0102] Furthermore, since the ringing is suppressed or prevented, the switching time between the plurality of optical fibers at the light output port 6 is shortened, enabling faster switching operations.

[0103] More preferably, V2(V) is supplied to the MEMS mirror (MEMS1) during either the transition from V1a(V) to 0(V) or the transition from 0(V) to V1b(V), thereby making it possible to suppress or eliminate the occurrence of resonance on either the X-axis or Y-axis of the oscillation axis of the oscillation part 2a of the MEMS mirror (MEMS1).

[0104] More preferably, both the X-axis control voltage and the Y-axis control voltage are set to V2 (V), regardless of the change in sign in the X-axis and / or Y-axis directions when switching between optical fibers at the light output port 6. By setting in this way, it is possible to further suppress or eliminate the occurrence of resonance in either the X-axis or Y-axis oscillation axis of the oscillating part 2a of the MEMS 1.

[0105] Considering the need to supply a post-transition control voltage at the time (timing) when the oscillating part 2a has swung to the set angle, it is preferable that V2 (V) be supplied at a single voltage value, whether it is during the transition from V1a (V) to 0 (V) or during the transition from 0 (V) to V1b (V), as shown in Figures 8, 10, and 12. The reason for this is that, compared to supplying V2 (V) multiple times at multiple voltage values, it is possible to simplify control of the voltage supplied to the MEMS mirror (MEMS1), reduce the number of voltage parameters, and easily control the voltage.

[0106] Note that one voltage value for V2(V) is expressed as one voltage value in the sense that the voltage value of V2(V) is set to one step between less than V1a(V) or less than V1b(V) and more than 0(V). Note that the voltage value of V2(V) can be set arbitrarily within the range of less than V1a(V) or less than V1b(V) and more than 0(V), and is therefore not limited to one value.

[0107] The length of time for supplying V2(V) can be set arbitrarily, and it should be set to a length that can suppress or prevent resonance in the oscillation of each axis of the two support parts 3a, 3b, or that can suppress or prevent unnecessary oscillation around one of the axes.

[0108] As shown in FIGS. 7 and 8 or 11 and 12, when the transition time of either the X-axis control voltage or the Y-axis control voltage is long and the transition times to the desired set angles for the X-axis and Y-axis of the oscillating part 2a are different, resonance of the oscillating part 2a is suppressed or eliminated as the supply of the control voltage for the axis with the long transition time begins.

[0109] It is more preferable to synchronize the X-axis control voltage and the Y-axis control voltage and supply them to the MEMS 1. The reason for this is that even if resonance or unnecessary oscillation occurs around one of the support parts (3a, 3b) of the MEMS 1 as the oscillation axis, voltage can be supplied to the other support part at the time the resonance or oscillation occurs. Therefore, even if resonance or unnecessary oscillation occurs around one support part of the MEMS 1 as the oscillation axis, it is possible to generate oscillation around the other support part as the oscillation axis in a direction that suppresses the resonance or oscillation. Therefore, even if resonance or unnecessary oscillation around one oscillation axis occurs, it can be quickly resolved.

[0110] In this embodiment, synchronization means that the timing at which control of the oscillating part 2a of the MEMS 1 is started by the start of supply of V2 (V) is the same between the two support parts 3a and 3b.

[0111] It is more desirable that there is a time (timing) when both the X-axis control voltage and the Y-axis control voltage V2 (V) are simultaneously supplied to the MEMS 1. In other words, there is a time when the voltages V2 (V) are supplied overlapping on the time axis of each voltage supply in Figures 8, 10, and 12.

[0112] By simultaneously supplying both V2(V) to MEMS1, even if resonance or unwanted oscillation occurs around one support part of MEMS1 as the oscillation axis, a control voltage can be supplied to the other support part. Therefore, even if resonance or unwanted oscillation occurs around one support part of MEMS1 as the oscillation axis, it is possible to generate oscillation around the other support part as the oscillation axis in a direction that suppresses the resonance or oscillation. Therefore, even if resonance or unwanted oscillation around one axis occurs, it can be quickly converged.

[0113] 13, by setting the time interval T0 to a minimum and immediately transitioning from 0(V) to V2(V) or V1b(V) after setting V1a(V) to 0(V), the switching time between the multiple optical fibers at the light output port 6 can be further reduced, thereby enabling faster switching operations.

[0114] 7 to 12, the step rises or falls of the X-axis and Y-axis control voltages are shown enlarged and diagonally to make it easier to see the time-dependent change in the supply of control voltage. This is because the step rises or falls of the X-axis and Y-axis control voltages may overlap. However, as will be shown in the examples below, the rises or falls of the steps actually measured are vertical or nearly vertical.

[0115] It is preferable that the MEMS 1 has a structure in which the central axes of the two support parts 3a and 3b are perpendicular to each other, as shown in FIG. 1. This is because the mutually perpendicular central axes of the two support parts 3a and 3b make it easier to control the oscillation angle of the oscillating part 2a. Therefore, it is possible to more easily suppress or prevent resonance of the oscillating part 2a. Furthermore, it is also possible to more easily suppress or prevent unnecessary oscillation around one axis. Therefore, it is possible to more easily converge resonance or unnecessary oscillation around one axis.

[0116] This embodiment can be modified in various ways, and the MEMS may have a structure in which the support portion 3 a is connected to the oscillating portion 2 b, and the support portion 3 b is connected to the oscillating portion 2 a. Furthermore, the number of optical fibers in each optical fiber array of the light output port 6, the number of optical fiber arrays, and the optical connection structure between the MEMS 1 and the light input / output ports (5, 6) in Figure 2 are not limited to this embodiment and can be modified.

[0117] Examples of the present invention will be described below, but the present invention is not limited to only the following examples. [Example]

[0118] The structure of the MEMS mirror in this example was an electrostatic comb-type MEMS1 (hereinafter referred to as MEMS) shown in Figure 1. The MEMS optical switch in this example was a 1x63 optical switch, in which the light input port was configured with one optical fiber and the light output port was configured with a total of 63 optical fibers, as shown in Figure 4. The optical connection structure between the MEMS and the light input / output port was a structure in which they were arranged face-to-face via a lens 7, as shown in Figure 2. Furthermore, the X-axis and Y-axis, which are the two oscillation axes of the MEMS, and the X-axis and Y-axis of the light output port were aligned with each other and set as common axes.

[0119] The optical fiber constituting the light input port was a single-mode optical fiber made of quartz. The optical fiber at the light output port was switched from the optical fiber arranged third from the right in the optical fiber array 6e in the fourth layer from the top in the first quadrant shown in Figure 4 to the optical fiber arranged second from the right in the optical fiber array 6e in the first quadrant via the optical fiber arranged at intersection 0. To switch between the optical fibers at the light output port in this way, a control voltage was supplied to the MEMS in the voltage value (Voltage)-supply time (Time) state shown in Figure 14. Both the X-axis control voltage (X voltage) and the Y-axis control voltage (Y voltage) were set to 0 (V).

[0120] As shown in Figure 14, an X voltage of 21.78 (V) and a Y voltage of 21.38 (V) were supplied to the MEMS starting from a supply time of 0.5 ms (milliseconds). By supplying these X and Y voltages, the angle of the MEMS mirror was swung and set so that it would optically connect to the optical fiber arranged third from the right in the optical fiber array 6e in the first quadrant shown in Figure 4. This is the state before switching the optical connection of the optical fiber at the light output port.

[0121] From this state, in order to switch the optical connection of the desired optical fiber to the second optical fiber from the right in the optical fiber array 6e in the first quadrant as the optical fiber connection switching destination, the X voltage is transitioned from 21.78 (V) to 28.21 (V) at the time of supply time 1.78 ms, and the Y voltage is transitioned from 15.75 (V) to 21.78 (V) at the time of supply time 1.91 ms. During this transition, the voltage supply state is set to the arrangement position of the optical fiber at intersection 0, that is, the control voltage is set to 0 (V).

[0122] The time interval T0 (ms or milliseconds) is the time interval from the transition of the Y voltage to 0 (V) to the start of the rise of the X voltage from 0 (V), and was set to 0.02 ms.

[0123] Furthermore, V2 (V) was set to a single voltage value throughout all transitions. All transitions refer to the transitions of the X and Y voltages from 21.78 V or 21.38 V to 0 V, and from 0 V to 28.21 V or 21.78 V, during which V2 (V) was supplied to the MEMS. The X voltage V2 (V) was supplied at a voltage value of 14.94 V for a supply time of 0.74 ms to 1.20 ms, or at a voltage value of 20.97 V for a supply time of 1.34 ms to 1.78 ms. The Y voltage V2 (V) was supplied at a voltage value of 14.94 (V) for a supply time of 0.75 ms to 1.30 ms, or at a voltage value of 15.75 (V) for a supply time of 1.35 ms to 1.91 ms. The voltage values ​​(V) and supply times (ms) of the X and Y voltages are all rounded down to two decimal places.

[0124] The control method for the MEMS optical switch of this embodiment simplifies the control of the voltage supplied to the MEMS mirror (MEMS) and reduces the number of voltage parameters. This makes it possible to easily control the voltage even when the light output port is multi-channel and controlled across four quadrants.

[0125] Furthermore, by reducing or suppressing the number of voltage parameters, even if the multi-channel configuration is implemented, the number of voltage parameters can be stored in the memory mounted on the drive substrate of the MEMS optical switch.

[0126] Furthermore, it was confirmed that the supply of V2 (V) can suppress or prevent the resonance of the oscillating part of the MEMS (2a in Figure 1), and as shown in Figure 15, ringing in the light emission to the optical fiber that constitutes the light emission port can be suppressed or prevented, thereby shortening the optical response time. [Explanation of symbols]

[0127] 1. Electrostatic comb-type MEMS 2a, 2b Swinging part 2a1, 2b2 outer comb teeth 2b1, 4a inner comb teeth 3a, 3b Support part 4 Outer fixing frame 5. Optical input port 5a Optical fiber constituting the optical input port 6 Light output port 6a to 6h: Optical fiber arrays constituting the light output ports 7 Lenses 8a Light incident from the light input port 8b Light reflected by a MEMS mirror 0 Intersection of X and Y axes T0 0(V) setting time (seconds) θ is the angle of incidence of the incident light and the angle of reflection of the reflected light

Claims

1. a MEMS mirror and a light output port configured with a plurality of optical fibers; The switching region of the MEMS mirror is defined as an angular space defined by two mutually orthogonal oscillation axes, the X-axis and the Y-axis, and the oscillation directions, the positive and negative directions, An angular space is projected onto the end face of the optical fiber that constitutes the light output port, and the arrangement area of ​​the multiple optical fibers is divided into four quadrants, i.e., first to fourth quadrants, in which the X axis and the Y axis are divided into + areas and - areas, respectively; a control voltage is a voltage supplied to the MEMS mirror to control the angle of the MEMS mirror to a desired setting angle; The intersection of the X-axis and Y-axis is set to 0 (V) in the control voltage of the MEMS mirror, and the end face of one optical fiber of the light output port is made to correspond to the intersection. When switching the optical connection of light reflected by the MEMS mirror between optical fibers by swinging the MEMS mirror, in switching between the + and - regions of either or both of the X and Y axes, the axis direction where the sign of the region changes is set to 0 (V), A control method for a MEMS optical switch that inputs light into optical fibers of light output ports arranged in each of the four quadrants.

2. 2. The method for controlling a MEMS optical switch according to claim 1, wherein the switching between the + area and the - area is performed via the setting of 0 (V) in both the X-axis and Y-axis directions.

3. As the control voltage, the control voltage supplied to the MEMS mirror before switching the optical connection of the optical fiber is defined as V1a (V), and the control voltage supplied to the MEMS mirror in order to switch the optical connection to a desired optical fiber is defined as V1b (V), 3. A control method for a MEMS optical switch according to claim 1, wherein a voltage V2(V) that is less than V1a(V) or less than V1b(V) and greater than 0(V) is supplied to the MEMS mirror during at least one of a transition from V1a(V) to 0(V) or a transition from 0(V) to V1b(V).

4. 4. The control method for a MEMS optical switch according to claim 3, wherein V2(V) is supplied to the MEMS mirror during either the transition from V1a(V) to 0(V) or the transition from 0(V) to V1b(V).

5. The method for controlling a MEMS optical switch according to claim 3, wherein V2 (V) is one voltage value.

6. The oscillation axes of the MEMS mirror are two axes, an X axis and a Y axis, which are orthogonal to each other at 90°, 2. The control method for a MEMS optical switch according to claim 1, wherein the X-axis and Y-axis, which are the oscillation axes of the MEMS mirror, are aligned with the X-axis and Y-axis, which define the placement area of ​​the light output port.

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