JP5243317B2 - Optical switch and optical switch control method - Google Patents

Description

  The present invention relates to an optical switch used in a communication optical transmission device, a wavelength routing device, and the like, and an optical switch control method.

  In recent years, in the field of optical communication, high-speed communication utilizing the characteristics of light has been realized by transmitting an optical signal to a partner without converting it into an electrical signal. Also, it has been realized to perform large-capacity optical transmission using one optical fiber by WDM (Wavelength Division Multiplexing) technology that multiplexes one optical signal corresponding to one wavelength. With the development of such optical communication technology, an optical switch that switches a path without converting an optical signal into an electric signal or the like has attracted attention.

  The optical switch has been promoted to have higher functionality as the optical communication network becomes larger. Conventionally, a simple 1 × 2 switch having one input port and two output ports has been used. However, in recent years, it has hundreds of input ports and output ports and can perform optical path control in units of ten thousand units. A matrix switch that can be used, a wavelength selection switch that selects an arbitrary wavelength from several tens of wavelengths, and outputs the selected wavelength from any of a plurality of output fibers have been proposed. A spatial optical system optical switch can realize these switches with high functionality and small size.

  The spatial optical system optical switch realizes high functionality and miniaturization by three-dimensionally arranging spatial optical components such as lenses and mirrors together with optical fibers. For such a spatial optical switch, a micromirror device (see, for example, Patent Document 1) created by MEMS (Micro Electro Mechanical Systems) technology is often used. The MEMS micromirror device is a device that applies a voltage to an electrode disposed opposite to a mirror and rotates the mirror around a rotation axis by an electrostatic force generated between the electrode and the mirror. Since the MEMS micromirror device can rotate the mirror by a plurality of rotating shafts, for example, in addition to the first rotating shaft that realizes switching of the optical path, the MEMS micromirror device has a first orthogonal to the first rotating shaft. The optical loss can be controlled by tilting the mirror about the rotation axis 2 and the power of the optical signal passing through the mirror can be controlled to an arbitrary value. The optical power control is used, for example, in a WDM optical network to suppress power variation between optical signals caused by a wavelength gain / loss difference in an optical transmission line. Since this function is related to the number of nodes that can be connected, it is an indispensable function for future wavelength selective switches for wavelength division multiplexing optical networks.

  Such a wavelength selective switch is required to have high optical performance as the optical network becomes larger. For example, when an optical signal passes through multiple nodes, an optical amplifier is provided to compensate for the optical loss. However, the wavelength selective switch has a transmission spectrum that can amplify only the necessary signal component. The spectrum is required to pass only the necessary band. In addition, since the number of ports also increases, the optical signal level that leaks to the adjacent ports, generally called port crosstalk (PXT), must be sufficiently suppressed below the required value.

  An example of such a wavelength selective switch is shown in FIGS. Here, the wavelength selective switch 100 shown in FIG. 13 adds a plurality (maximum m-waves) of channel (wavelength) signals input from a plurality of input ports and outputs the combined signal from one output port. Switch. On the other hand, the wavelength selective switch 200 shown in FIG. 14 is a drop-type wavelength selective switch that outputs a plurality of channel signals (maximum m waves) input from one input port from one of the plurality of output ports. is there. In FIG. 13 and FIG. 14, equivalent components are denoted by the same names and reference numerals, and description thereof is omitted as appropriate.

  The wavelength selective switch 100 shown in FIG. 13 includes n input-side optical fibers 101-1 to 101-n that function as input ports, one output-side optical fiber 102 that functions as an output port, and an input-side optical fiber. A diffraction grating 103 that diffracts input light from 101-1 to 101-n and demultiplexes it into a maximum of m optical signals having different wavelengths, and reflects an optical signal diffracted by the diffraction grating 103 for each wavelength. MEMS mirror devices 104-1 to 104-m that output from the output-side optical fiber 102; a demultiplexer 105 that demultiplexes the optical signal branched from the output-side optical fiber 102 for each of m specific wavelengths; Photodiodes 106-1 to 106-m that monitor each light demultiplexed by the demultiplexer 105 and convert it into electrical signals, and detection of the photodiodes 106-1 to 106-m An A / D converter 107 that A / D converts the result and outputs an optical power value, and controls the driving of the MEMS mirror devices 104-1 to 104-m based on the output from the A / D converter 107 The mirror control circuit 108 is provided. Here, each mirror of the MEMS mirror devices 104-1 to 104-m is rotatable about the x axis in the direction in which the mirrors are arranged and the y axis orthogonal to the x axis. The optical fibers 101-1 to 101-n are arranged in the direction along the y-axis.

  The wavelength selective switch 200 shown in FIG. 14 diffracts input light from one input-side optical fiber 101, n output-side optical fibers 102-1 to 102-n, and the input-side optical fiber 101, and wavelength. Diffracting grating 103 which demultiplexes into a maximum of m optical signals having different wavelengths, and the optical signal diffracted by this diffraction grating 103 is reflected for each wavelength and output from the corresponding output side optical fibers 102-1 to 102-n. MEMS mirror devices 104-1 to 104-m to be combined, a combiner 109 for combining the outputs from the output-side optical fibers 102-1 to 102-n, and m specific light beams combined by the combiner 109 A demultiplexer 105 that demultiplexes each wavelength, a photodiode 106-1 to 106-m that monitors each light demultiplexed by the demultiplexer 105 and converts it into an electrical signal, and the photodiode 1 The A / D converter 107 that A / D converts the detection results of 6-1 to 106-m and outputs the value of the optical power, and the MEMS mirror device 104-based on the output from the A / D converter 107 And a mirror control circuit 108 that controls driving of 1 to 104-m. Here, each mirror of the MEMS mirror devices 104-1 to 104-m is rotatable about the x axis in the direction in which the mirrors are arranged and the y axis perpendicular to the x axis, and the output side The optical fibers 102-1 to 102-n are arranged on the locus of the light beam when the mirror is rotated around the x axis.

  Here, the difference between the wavelength selective switch 100 shown in FIG. 13 and the wavelength selective switch 200 shown in FIG. 14 is that the N-input 1-output Add type or the 1-input N-output Drop type is in the input / output direction. The difference and the configuration for monitoring the signal light power on the output side accompanying this, that is, in the wavelength selective switch 100 shown in FIG. 13, a part of the optical power from the output side optical fiber 102 is simply branched to form a channel (wavelength 14), the wavelength selective switch 200 shown in FIG. 14 branches the optical signal from each of the plurality of output side optical fibers 102-1 to 102-n. Then, after the signals are combined into one by the combiner 109, the signal is input to the demultiplexer 105 for separating the signals for each channel. Other configurations and operating principles are the same for both.

  For convenience, FIG. 15 shows a simplified version of the wavelength selective switch 100 shown in FIG. 13 with a focus on one channel.

  A wavelength selective switch 100 shown in FIG. 15 includes inputs from n input side optical fibers 101-1 to 101-n, one output side optical fiber 102, and input side optical fibers 101-1 to 101-n. A diffraction grating 103 that diffracts light, a MEMS mirror device 104 that reflects an optical signal diffracted by the diffraction grating 103 and outputs it from the output side optical fiber 102, and a part of the output from the output side optical fiber 102 is branched. A coupler 110 for converting the optical signal branched by the coupler 110 into an electrical signal, an A / D converter 107 for A / D converting the electrical signal from the photodiode 106, and the A / D And a mirror control circuit 108 for controlling the driving of the MEMS mirror device 104 based on the output from the D converter 107. Here, the input side optical fibers 101-1 to 101-n, the output side optical fiber 102, the diffraction grating 103, and the MEMS mirror device 104 constitute a spatial optical system switch unit 300. Further, the photodiode 106, the A / D converter 107, and the mirror control circuit 108 constitute a drive control unit 400.

  Here, as shown in FIG. 16A, a specific structural example of the MEMS mirror device that rotates around two axes, the x axis and the y axis orthogonal to the x axis, will be described. The mirror 1041 of the MEMS mirror device 104 is connected to any one of n input ports and one output port with respect to the x-axis, that is, in any rotation direction around the x-axis. It rotates so that there is a minimum loss between the input port and one output port. This rotates to move the direction of the optical signal in the direction in which the input ports are arranged. On the other hand, since the mirror 1041 rotates about the y axis orthogonal to the x axis with respect to the y axis, the mirror 1041 rotates to move the direction of the optical signal in a direction orthogonal to the direction in which the input ports are arranged. Therefore, in order to control the coupling rate from the input port to the output port, that is, the loss, it is possible to rotate either the x-axis or the y-axis, but the rotation around the x-axis governing the movement of the ports in the alignment direction is possible. The rotation is mainly used for the loss control, and the rotation around the y-axis, which controls the movement in the direction orthogonal to the port arrangement direction, is mainly used for the loss control.

  In such a wavelength selective switch 100, when performing negative feedback control, the control device 108 sets the deviation between the output power of the optical signal obtained by the photodiode 106 and the A / D converter 107 and the target value to zero. Thus, the mirror 1041 of the MEMS mirror device 104 is rotated.

  For example, as shown in FIGS. 16A to 16D, the MEMS mirror device 104 includes a mirror 1041 having a gimbal structure, and electrodes 1042 a to 1042 d disposed to face the mirror 1041. . The electrodes 1042a to 1042d are provided on the same plane substantially parallel to the main surface of the mirror 1041, the electrodes 1042a and 1042b are symmetric with respect to the x axis, and the electrodes 1042c and 1042d are symmetric with respect to the y axis. Often arranged. Since the potential of the mirror 1041 is the same as the ground potential, when a voltage is applied to the electrodes 1042a to 1042d, an electrostatic attractive force is generated between the electrodes 1042a to 1042d and the mirror 1041, and this electrostatic attractive force. And the mirror 1041 tilts to an angle at which the restoring force of the torsion spring that supports the mirror 1041 is balanced. Since there are two rotation directions of the mirror 1041 around the x axis and the y axis, if there are two voltages (that is, control variables) for controlling the rotation, the angle of the two axes can be arbitrarily controlled. In addition, it is easier to construct a control method by minimizing the number of variables than handling many variables. Therefore, four voltages (Va, Vb, Vc, Vd: respective voltages (hereinafter referred to as electrode voltages) to be applied to the four electrodes 1042a to 1042d are expressed by the following two equations (1) and (2). The voltages are expressed as Vx and Vy.

2 Vx = Va−Vb (1)
2 Vy = Vc−Vd (2)

  By using the above equations (1) and (2), it is possible to treat the voltage that controls the rotation about the x-axis as Vx and the voltage that controls the rotation about the y-axis as Vy. Hereinafter, the voltages Vx and Vy are referred to as axial voltages. Normally, in the case of a biaxially driven mirror, in addition to the gimbal structure mirror as shown in FIGS. 16 (a) to 16 (d), an axial voltage with reduced variables is used instead of the electrode voltage. In many cases, mirror drive control is performed. Further, the relationship between the electrode voltage and Vx, Vy is not necessarily limited to the relationship shown in the above formulas (1) and (2), and other relational expressions are adopted in consideration of the mirror characteristics and the like. There is also.

  In the MEMS mirror device 104, when the axial voltage Vx is changed, the mirror 1041 rotates about the x axis. As shown in FIG. 15, since the input ports are arranged in a direction orthogonal to the x-axis, there are as many rotation angles around the x-axis as connecting the input ports and output ports by the number n of the input ports. . Therefore, the number V of the input ports also exists as the voltage Vx that optimally couples each input port and output port.

  On the other hand, in the MEMS mirror device 104, when the axial voltage Vy is changed, the mirror 1041 rotates about the y axis. As shown in FIG. 15, since the input ports are arranged in a direction parallel to the y-axis, if an input port and an output port are optimally coupled (in a state where the loss is minimized), the y-axis is rotated. If the rotation is given, the coupling state deteriorates and the loss between the input port and the output port increases. At this time, since the mirror is rotated in the direction orthogonal to the direction in which the input ports are arranged, the coupling state of the other ports is not affected. That is, the rotation around the y-axis only reduces the coupling efficiency with a certain port and has little influence on other ports. For this reason, the rotation around the y-axis is mainly used for loss control. The loss characteristic around the y-axis shows a mountain shape where the peak is at the point where the loss is the smallest, and the loss increases as it deviates from this peak. Therefore, there is only one voltage Vy that optimally couples a certain input port and output port.

  That is, as shown in FIG. 17, there are peaks for N ports according to the number of input ports in the direction of the Vx axis. On the other hand, there is only one peak for each port in the Vy axis direction. Therefore, the loss contour map on the Vx-Vy plane shows a characteristic shape in which N ellipses elongated in the Vy axis direction are arranged in the Vx direction. Depending on the employed mirror, the mirror may operate only in the positive direction of Vx or Vy. In such a case, the loss contour map is obtained by extracting only the operating range of the mirror from FIG.

  18A to 18C show the difference between the case where the variable for controlling the loss is taken as Vx and the case where it is taken as Vy.

  Basically, the loss control is performed using the axial voltage Vy, but it is also possible to perform the loss control by rotating the mirror 1041 only in the x-axis direction using the axial voltage Vx as shown in FIG. 18C. However, in this case, if the loss of a certain port is to be reduced, a phenomenon called so-called crosstalk occurs in which light leaks to a port adjacent to that port. Since this crosstalk becomes noise with respect to the optical signal, it must be suppressed to a specified value or less. This specified value depends on the network design, but a low value such as less than −30 dB is required. In order to change the loss and keep the crosstalk small, it is optimal to control the loss by rotating the mirror 1041 around the y-axis orthogonal to the x-axis as shown in FIG. 18B.

  However, when loss control is performed using only the y-axis, other optical characteristics may be degraded. Specifically, when the value of Vy is increased and the mirror 1041 is rotated at a large angle around the y axis, the diffracted light from the end face of the mirror 1041 remains in the transmission spectrum, and the end of the transmission band. Loss may remain without decreasing, and a spectrum shape in which the vicinity of both ends of the transmission band protrudes in a mountain shape may occur. This is called Rabbit Ear because it looks like it pops out like a rabbit ear. This phenomenon reduces the transmission band of the network in an optical network that passes through a plurality of wavelength selective switches and optical amplifiers because the “ear” portion is also repeatedly amplified and “grows”. Therefore, it is required to make Rabbit Ear small.

  From the viewpoint of reducing Rabbit Ear, as shown in FIG. 18C, it is desirable to control loss using only rotation around the x axis where the direction of the diffracted light at both ends of the mirror does not fall within the transmission spectrum. However, in this case, the problem of crosstalk occurs as described above.

  As described above, crosstalk and Rabbit Ear are difficult to solve by using either the x-axis or the y-axis as the axis for controlling the loss. Thus, as shown in FIGS. 19A and 19B, the mirror 1041 is rotated around the x axis in the vicinity of the peak, and the mirror 1041 is rotated around the y axis when deviating from the peak. It has been proposed to solve. Since the Rabbit Ear has a large loss, that is, it becomes prominent at a position away from the peak, it makes sense to rotate the mirror 1402 around the x axis in the initial stage.

  However, when the axis to be rotated is switched, the target variable when switching the axis must be changed. For example, on the elliptical loss contour line as shown in FIG. 17, in the Vx direction and the Vy direction, Loss characteristics will change greatly. For this reason, when negative feedback control is performed on the power, the control parameter must be reset every time the axis is switched in order to keep the feedback amount optimal, resulting in complicated control. End up.

  For this reason, instead of switching the rotation operation about the x axis and the y axis alternately as in the prior art, Vx and Vy are simultaneously changed with a predetermined relationship, and the loss increases. By rotating not only around the y axis but also around the x axis, Rabbit Ear can be suppressed along with crosstalk. In this way, since the loss characteristics change continuously, it is possible to realize optical power control without resetting variables and control parameters.

Here, the predetermined relationship described above indicates that one of Vx and Vy is set as the other dependent variable. For example, as shown in the following expression (3), it means that Vy is a linear function of Vx. In the following equation (3), (Vx ₀ , Vy ₀ ) is a coordinate indicating a peak on the Vx-Vy plane. A is a constant that is not zero.

Vy = A (Vx−Vx ₀ ) + Vy ₀ (3)

  Further, Vx and Vy may be represented by the following expressions (4) and (5) using arbitrary parameters. In the following formulas (4) and (5), Vt is used as an arbitrary parameter. B is a constant that is not zero.

Vx = A · Vt + Vx ₀ (4)
Vy = B · Vt + Vy ₀ (5)

  When the optical power is kept constant by negative feedback control, for example, Vx is set as the control voltage in the case of the expression (3), and Vt is set in the cases of the expressions (4) and (5). The control voltage is a variable to which a compensation amount corresponding to the deviation is added, and the control amount such as optical power and attenuation amount is controlled by adjusting the control voltage.

  As described above, if the crosstalk can be made less than the allowable value and the Rabbit Ear can be suppressed by rotating the mirror around the x axis and then rotating around the y axis, the formula for calculating the control voltage is It is more appropriate to express a high-order function as in the following equation (6) than as a linear function as in the above equation (3).

Vy = A (Vx−Vx ₀ ) ^α + Vy ₀ (6)

  In the above formula (6), α is an integer of 2 or more. 20A and 20B show a locus on a loss contour line drawn by a high-order function such as the above equation (6) and loss characteristics with respect to a control variable. As can be seen from FIGS. 20A and 20B, although the differential value of the loss characteristic is continuous, the same Rabbit Ear suppression effect as that of the loss characteristic shown in FIGS. 19A and 19B can be obtained. In this way, by using a higher-order function, it is possible to realize a drive that first rotates in the x-axis direction and increases the rotation in the y-axis direction as Vx increases.

JP 2003-057575 A

  However, if high-order functions are introduced in the calculation of the shaft voltages Vx and Vt, the calculation becomes complicated and the maintenance of overflow and calculation accuracy must be considered, so that a complicated control circuit is required, resulting in an increase in cost. Invited to increase.

  Accordingly, an object of the present invention is to provide an optical switch and an optical switch control method capable of realizing crosstalk and Rabbit Ear suppression at a low cost without using a high-order function.

In order to solve the above-described problems, an optical switch according to the present invention includes a single optical input unit that inputs input light, a plurality of optical output units that output output light, or a plurality of optical input units that input input light. An optical input unit and at least one optical input unit that inputs input light, such as an optical output unit that outputs output light, at least one optical output unit that outputs output light, and an optical input unit or an optical output unit A mirror device having a mirror rotatably supported with respect to an x-axis used for selection and a y-axis orthogonal to the x-axis, and a plurality of electrodes arranged opposite to the mirror; An optical switch including a drive control unit that applies and rotates the mirror about the x-axis and the y-axis, and a detection unit that detects the light intensity of output light output from the light output unit. The control unit corresponds to the target light intensity A control voltage calculation unit for calculating a control voltage, and the shaft voltage calculation unit for calculating the axial voltage Vx and Vy to the mirror from the control voltage respectively rotated in the x-axis and y-axis, rotating the mirror about the x-axis Based on the relationship between the rotation angle of the mirror and the electrode voltage when the bias voltage Vxbias is applied to the electrode for applying the bias voltage and the bias voltage Vybias is applied to the electrode for rotating the mirror about the y-axis , Vx and Vy An electrode voltage to be applied to each of the electrodes, an electrode voltage control unit that applies the electrode voltage to the corresponding electrode, a comparison unit that obtains a deviation between a detection result detected by the detection unit and a target light intensity; And a compensation unit that adds a compensation amount according to the deviation output from the comparison unit to the control voltage and negatively feeds back the deviation to the control voltage.

Another optical switch according to the present invention includes one optical input unit that inputs input light and a plurality of optical output units that output output light, or a plurality of optical input units that input input light and output light. At least one light input section for inputting input light, such as one light output section for output, at least one light output section for outputting output light, and an x-axis used for selecting the light input section or the light output section; A mirror device having a mirror supported so as to be rotatable with respect to a y-axis orthogonal to the x-axis, a plurality of electrodes arranged opposite to the mirror, and applying an electrode voltage to the electrode to make the mirror an x-axis An optical switch including a drive control unit that rotates about the rotation and the y-axis, and a detection unit that detects the light intensity of output light output from the light output unit, and the drive control unit is a target Control to calculate control voltage corresponding to light intensity A pressure calculator, an axial voltage calculator for calculating axial voltages Vx and Vy for rotating the mirror around the x-axis and y-axis from the control voltage, and an electrode voltage to be applied to each electrode from Vx and Vy, An electrode voltage control unit that applies this electrode voltage to the corresponding electrode, a comparison unit that obtains a deviation between the detection result detected by the detection unit and the target light intensity, and a deviation output from the comparison unit A compensation unit that adds a compensation amount to the control voltage and negatively feeds back the deviation to the control voltage. The electrodes include electrodes a and b that control the rotation of the mirror about the x-axis and the mirrors about the y-axis of the mirror. In the electrode voltage control means, when the electrode voltage applied to the electrode a is Va and the electrode voltage applied to the electrode b is Vb, the electrode voltage control means 2 Vx = Va-Vb and the voltage Vy Is expressed as 2 Vy = Vc−Vd where the electrode voltage applied to the electrode c is Vc and the electrode voltage applied to the electrode d is Vd, and the relationship between the shaft voltage Vx and the shaft voltage Vy is a constant A If (≠ 0), Vy = A (Vx−Vx ₀ ) + Vy ₀ , and the electrode voltages Va, Vb, Vc, and Vd have peak coordinates that minimize light loss on the Vx−Vy plane ( Vx ₀ , Vy ₀ ), the bias voltage applied to the shaft voltage Vx is Vxbias, the bias voltage applied to the shaft voltage Vy is Vybias, and the ratio of the voltage realizing the maximum rotation angle around the x axis of the mirror and Vxbias is η _x, when the ratio between the voltage and Vybias realizing the maximum pivot angle of the y-axis of the mirror and eta _y, when Vx ≧ 0, Va = 2 ( 1-η x) Vx + Vxbias, Vb = -2η x Vx + Vxbias , Vx <0 _{When, Va = 2η x Vx + Vxbias} , Vb = -2 (1-η x) Vx + Vxbias, when Vy ≧ 0, Vc = 2 ( 1-η y) Vy + Vybias, Vd = -2η y Vy + Vybias, when Vy <0, Vc = 2η _y Vy + Vybias, Vd = −2 (1−η _y ) Vy + Vybias.

Another optical switch according to the present invention includes one optical input unit that inputs input light and a plurality of optical output units that output output light, or a plurality of optical input units that input input light and output light. At least one light input section for inputting input light, such as one light output section for output, at least one light output section for outputting output light, and an x-axis used for selecting the light input section or the light output section; A mirror device having a mirror supported so as to be rotatable with respect to a y-axis orthogonal to the x-axis, a plurality of electrodes arranged opposite to the mirror, and applying an electrode voltage to the electrode to make the mirror an x-axis A drive control unit that rotates about the rotation and the y-axis, a detection unit that detects the light intensity of the output light output from the light output unit, and a component that demultiplexes the output light detected by the detection unit for each wavelength. And an optical switch having a wave part A photoelectric conversion unit that converts the output light demultiplexed by the demultiplexing unit into an electrical signal, an A / D conversion unit that digitally converts the electrical signal and outputs an optical power value of the output light, and an output light A comparison unit for obtaining a deviation between the light intensity value and the target value of the light intensity, a compensation amount calculation unit for obtaining a compensation amount proportional to the deviation output from the comparison unit, and negatively feeding back the compensation amount to the control voltage The adding unit, the delay unit holding the control voltage with the compensation amount for an arbitrary control period, and the mirror around the x-axis and the y-axis from the control voltage with the compensation amount. An axial voltage calculation unit that calculates the axial voltages Vx and Vy to be moved, an electrode voltage control unit that calculates an electrode voltage to be applied to each electrode from Vx and Vy, and applies this electrode voltage to the corresponding electrode, Controls the rotation of the mirror around the x axis Electrodes a and b, and electrodes c and d for controlling the rotation of the mirror about the y-axis. In the electrode voltage control means, the axial voltage Vx is the electrode voltage applied to the electrode a Va, the electrode b When the electrode voltage is Vb applied to, is represented by 2 Vx = Va-Vb, voltage Vy is the electrode voltage applied to the electrode c Vc, when the electrode voltage applied to the electrodes d and Vd, 2 Vy = Vc−Vd, and the relationship between the shaft voltage Vx and the shaft voltage Vy is represented by Vy = A (Vx−Vx ₀ ) + Vy ₀ when the constant is A (≠ 0), and the electrode voltages Va, Vb , Vc, Vd are the coordinates of the peak at which the optical loss is minimum on the Vx-Vy plane (Vx ₀ , Vy ₀ ), the bias voltage applied to the axial voltage Vx is Vxbias, and the bias voltage applied to the axial voltage Vy is Vybias, maximum rotation angle around the x-axis of the mirror Vxbias is the ratio of the voltage that achieves η _x , and the ratio of the voltage that realizes the maximum rotation angle around the y-axis of the mirror and Vybias is η _y. η _x ) Vx + Vxbias, Vb = −2η _x Vx + Vxbias, Vx <0, Va = 2η _x Vx + Vxbias, Vb = −2 (1−η _x ) Vx + Vxbias, Vy ≧ 0, Vc = 2 (1−η _y ) Vy + Vybias, Vd = -2η y Vy + Vybias, when Vy <0, is characterized in that represented by _{Vc = 2η y Vy + Vybias,} Vd = -2 (1-η y) Vy + Vybias.

Another optical switch according to the present invention includes one optical input unit that inputs input light and a plurality of optical output units that output output light, or a plurality of optical input units that input input light and output light. At least one light input section for inputting input light, such as one light output section for output, at least one light output section for outputting output light, and an x-axis used for selecting the light input section or the light output section; A mirror device having a mirror supported so as to be rotatable with respect to a y-axis orthogonal to the x-axis, a plurality of electrodes arranged opposite to the mirror, and applying an electrode voltage to the electrode to make the mirror an x-axis An optical switch including a drive control unit that rotates about the rotation and the y-axis, and the drive control unit includes a control voltage calculation unit that calculates a control voltage corresponding to a target light intensity, and a control voltage Rotate the mirror about the x and y axes Bias and the axis voltage calculating unit that calculates the axial voltage Vx and Vy is respectively rotated, the mirror bias voltage Vxbias the electrode for rotating the x-axis, the mirror electrode for rotating about the y-axis Based on the relationship between the rotation angle of the mirror when the voltage Vybias is applied and the electrode voltage, an electrode voltage to be applied to each electrode is calculated from Vx and Vy, and this electrode voltage is applied to the corresponding electrode. And a control unit.

Another optical switch according to the present invention includes one optical input unit that inputs input light and a plurality of optical output units that output output light, or a plurality of optical input units that input input light and output light. At least one light input section for inputting input light, such as one light output section for output, at least one light output section for outputting output light, and an x-axis used for selecting the light input section or the light output section; A mirror device having a mirror supported so as to be rotatable with respect to a y-axis orthogonal to the x-axis, a plurality of electrodes arranged opposite to the mirror, and applying an electrode voltage to the electrode to make the mirror an x-axis An optical switch including a drive control unit that rotates about the rotation and the y-axis, and the drive control unit includes a control voltage calculation unit that calculates a control voltage corresponding to a target light intensity, and a control voltage Rotate the mirror about the x and y axes An axial voltage calculation unit that calculates axial voltages Vx and Vy to rotate, an electrode voltage control unit that calculates an electrode voltage to be applied to each electrode from Vx and Vy, and applies this electrode voltage to the corresponding electrode, The electrodes include electrodes a and b for controlling the rotation of the mirror about the x-axis and electrodes c and d for controlling the rotation of the mirror about the y-axis. Is represented by 2 Vx = Va−Vb, where Va is the electrode voltage applied to the electrode a, and Vb is the electrode voltage applied to the electrode b, and the voltage Vy is the electrode voltage applied to the electrode c. When the electrode voltage applied to the electrode d is Vd, 2 Vy = Vc−Vd, and the relationship between the shaft voltage Vx and the shaft voltage Vy is Vy = A (Vx -Vx ₀₎ is represented by + Vy _0, electrode voltage Va, Vb Vc, Vd is, Vybias a bias voltage applied to the peak of the coordinate light loss is minimized in the Vx-Vy plane (Vx _0, Vy _0), the bias voltage applied to the shaft voltage Vx Vxbias, the axial voltage Vy If the ratio of the voltage that realizes the maximum rotation angle around the x axis of the mirror and Vxbias is η _x , and the ratio of the voltage that realizes the maximum rotation angle around the y axis of the mirror and Vybias is η _y , then Vx When ≧ 0, Va = 2 (1−η _x ) Vx + Vxbias, Vb = −2η _x Vx + Vxbias, when Vx <0, Va = 2η _x Vx + Vxbias, Vb = −2 (1−η _x ) Vx + Vxbias, Vy ≧ 0 when, Vc = 2 (1-η y) Vy + Vybias, Vd = -2η y Vy + Vybias, when _{Vy <0, Vc = 2η y} Vy + Vybias, Vd = -2 (1- is characterized in that represented by _y) Vy + Vybias.

In the optical switch, the relationship between the axial voltage Vx and the voltage Vy may be expressed as Vy = A (Vx−Vx ₀ ) ^α + Vy ₀ where ^α is an integer equal to or greater than 1.

  The optical switch further includes a storage unit that stores in advance the correspondence between the optical loss and the control voltage, and the control voltage calculation unit acquires the control voltage corresponding to the target optical loss from the storage unit. Also good.

  The optical switch further includes a storage unit that stores in advance an approximate expression of the control voltage that approximates the correspondence between the optical loss and the control voltage, and the control voltage calculation unit is based on the approximate expression stored in the storage unit. Thus, a control voltage corresponding to the target optical loss may be acquired.

The optical switch control method according to the present invention includes a single optical input unit that inputs input light and a plurality of optical output units that output output light, or a plurality of optical input units that input input light and output light. At least one light input unit for inputting input light, at least one light output unit for outputting output light, and an x-axis used for selecting the light input unit or the light output unit And a mirror device having a mirror supported so as to be rotatable with respect to a y-axis orthogonal to the x-axis, and a plurality of electrodes arranged to face the mirror, and applying an electrode voltage to the electrodes to make the mirror x A method for controlling an optical switch, comprising: a drive control unit that rotates about an axis and a y-axis; and a detection unit that detects a light intensity of output light output from the light output unit. Control that calculates the control voltage corresponding to the strength A voltage calculation step, the axial voltage calculating a shaft voltage Vx and Vy is respectively pivoted from the control voltage the mirror in the x-axis and y-axis, the bias voltage mirror electrode for rotating the x-axis Vxbias, an electrode voltage applied to each of the electrodes from Vx and Vy based on the relationship between the rotation angle of the mirror and the electrode voltage when the bias voltage Vybias is applied to the electrode for rotating the mirror about the y-axis. And a comparison step for obtaining a deviation between an electrode voltage control step for applying the electrode voltage to the corresponding electrode, a target light intensity of the detection result detected by the detection unit, and a comparison step A compensation step of adding a compensation amount corresponding to the deviation to the control voltage and negatively feeding back the deviation to the control voltage. Than is.

In addition, another optical switch control method according to the present invention includes: one optical input unit that inputs input light; a plurality of optical output units that output output light; or a plurality of optical input units that input input light; Used to select at least one light input unit that inputs input light, at least one light output unit that outputs output light, and the light input unit or light output unit, such as one light output unit that outputs output light A mirror device having a mirror rotatably supported with respect to the x-axis and a y-axis orthogonal to the x-axis, and a plurality of electrodes arranged to face the mirror, and applying an electrode voltage to the electrodes Is a control method for an optical switch, comprising: a drive control unit that rotates the X axis about the x axis and the y axis; and a detection unit that detects the light intensity of the output light output from the light output unit. Calculate the control voltage corresponding to the light intensity A control voltage calculation step, an axis voltage calculation step for calculating an axis voltage Vx and Vy for rotating the mirror around the x axis and the y axis, respectively, from the control voltage, and an electrode voltage applied to each electrode from Vx and Vy. The electrode voltage control step for applying the electrode voltage to the corresponding electrode, the comparison step for obtaining a deviation between the detection result detected by the detection unit and the target light intensity, and the deviation obtained by the comparison step A compensation step of adding the compensation amount to the control voltage and negatively feeding back the deviation to the control voltage. The electrodes include electrodes a and b for controlling the rotation of the mirror about the x axis, and the y axis of the mirror. The axial voltage Vx is composed of electrodes c and d for controlling the rotation of the rotation. The voltage Vx is 2 Vx = Va is the electrode voltage applied to the electrode a and Va is the electrode voltage applied to the electrode b. Represented by va-Vb, voltage Vy, when the electrode voltage applied to the electrode c Vc, and the electrode voltage applied to the electrodes d Vd, expressed in 2 Vy = Vc-Vd, axial voltage Vx and the axial The relationship of the voltage Vy is expressed as Vy = A (Vx−Vx ₀ ) + Vy ₀ when the constant is A (≠ 0), and the electrode voltages Va, Vb, Vc, and Vd are optical losses on the Vx−Vy plane. There peaks coordinate for the minimum _{(Vx 0, Vy 0),} Vxbias a bias voltage applied to the shaft voltage Vx, Vybias a bias voltage applied to the shaft voltage Vy, the maximum rotation angle of the x-axis of the mirror realized When the ratio of the voltage to Vxbias is η _x and the ratio of the voltage to achieve the maximum rotation angle around the y-axis of the mirror and Vybias is η _y , Va = 2 (1−η _x ) Vx + Vxbias, Vb = -2η x x + Vxbias, when _{Vx <0, Va = 2η x} Vx + Vxbias, Vb = -2 (1-η x) Vx + Vxbias, when Vy ≧ 0, Vc = 2 ( 1-η y) Vy + Vybias, Vd = -2η y Vy + Vybias, When Vy <0, Vc = 2η _y Vy + Vybias, Vd = −2 (1−η _y ) Vy + Vybias.

The optical switch control method according to the present invention includes a single optical input unit that inputs input light and a plurality of optical output units that output output light, or a plurality of optical input units that input input light and output light. At least one light input unit for inputting input light, at least one light output unit for outputting output light, and an x-axis used for selecting the light input unit or the light output unit And a mirror device having a mirror supported so as to be rotatable with respect to a y-axis orthogonal to the x-axis, and a plurality of electrodes arranged to face the mirror, and applying an electrode voltage to the electrodes to make the mirror x A drive control unit that rotates about the axis and the y-axis, a detection unit that detects the light intensity of the output light output from the light output unit, and the output light detected by the detection unit is demultiplexed for each wavelength. Control method of optical switch having demultiplexer A photoelectric conversion step for converting the output light demultiplexed by the demultiplexing unit into an electric signal, an A / D conversion step for digitally converting the electric signal and outputting a value of optical power of the output light, and output light Comparison step for obtaining a deviation between the light intensity value and the target value of the light intensity, a compensation amount calculating step for obtaining a compensation amount proportional to the deviation output from the comparison unit, and negatively feeding back the compensation amount to the control voltage An addition step, a delay step for maintaining the control voltage with the compensation amount added for an arbitrary control period, and a mirror around the x axis and the y axis from the control voltage with the compensation amount added. An axial voltage calculating step for calculating the axial voltages Vx and Vy to be moved, an electrode voltage to be applied to each electrode from Vx and Vy, and an electrode voltage control step for applying this electrode voltage to the corresponding electrode. The electrode is composed of electrodes a and b for controlling the rotation of the mirror about the x-axis and electrodes c and d for controlling the rotation of the mirror about the y-axis, and the axial voltage Vx is When the electrode voltage applied to the electrode a is Va and the electrode voltage applied to the electrode b is Vb, 2 Vx = Va−Vb, and the voltage Vy is the electrode voltage applied to the electrode c Vc, Assuming that the electrode voltage applied to the electrode d is Vd, 2 Vy = Vc−Vd, and the relationship between the shaft voltage Vx and the shaft voltage Vy is Vy = A (Vx− Vx ₀ ) + Vy ₀ , and the electrode voltages Va, Vb, Vc, and Vd are applied to the axial voltage Vx with the coordinates of the peak at which the optical loss is minimized on the Vx−Vy plane (Vx ₀ , Vy ₀ ). The bias voltage is Vxbias, and the bias voltage applied to the shaft voltage Vy is Vybia. s, where η _x is the ratio of the voltage that achieves the maximum rotation angle around the x axis of the mirror and Vxbias, and η _y is the ratio of the voltage that realizes the maximum rotation angle around the y axis of the mirror and Vybias. When Vx ≧ 0, Va = 2 (1−η _x ) Vx + Vxbias, Vb = −2η _x Vx + Vxbias, when Vy <0, Va = 2η _x Vx + Vxbias, Vb = −2 (1−η _x ) Vx + Vxbias, Vy ≧ When 0, Vc = 2 (1-η _y ) Vy + Vybias, Vd = -2η _y Vy + Vybias, when Vy <0, Vc = 2η _y Vy + Vybias, Vd = −2 (1-η _y ) Vy + Vybias It is characterized by.

In addition, another optical switch control method according to the present invention includes: one optical input unit that inputs input light; a plurality of optical output units that output output light; or a plurality of optical input units that input input light; Used to select at least one light input unit that inputs input light, at least one light output unit that outputs output light, and the light input unit or light output unit, such as one light output unit that outputs output light A mirror device having a mirror rotatably supported with respect to the x-axis and a y-axis orthogonal to the x-axis, and a plurality of electrodes arranged to face the mirror, and applying an electrode voltage to the electrodes A control voltage calculating step of calculating a control voltage corresponding to a target light intensity, and a control voltage calculating method, comprising: a drive control unit that rotates the X axis and the Y axis. The mirror from the x-axis and Electrodes for rotating the shaft voltage calculating a shaft voltage Vx and Vy is respectively rotated about the axis, the electrode for turning the mirror about the x-axis bias voltage Vxbias, the mirror about the y-axis Based on the relationship between the rotation angle of the mirror when the bias voltage Vybias is applied to the electrode and the electrode voltage, the electrode voltage applied to each electrode is calculated from Vx and Vy, and this electrode voltage is applied to the corresponding electrode. And an electrode voltage control step.

In addition, another optical switch control method according to the present invention includes: one optical input unit that inputs input light; a plurality of optical output units that output output light; or a plurality of optical input units that input input light; Used to select at least one light input unit that inputs input light, at least one light output unit that outputs output light, and the light input unit or light output unit, such as one light output unit that outputs output light A mirror device having a mirror rotatably supported with respect to the x-axis and a y-axis orthogonal to the x-axis, and a plurality of electrodes arranged to face the mirror, and applying an electrode voltage to the electrodes A control voltage calculating step of calculating a control voltage corresponding to a target light intensity, and a control voltage calculating method, comprising: a drive control unit that rotates the X axis and the Y axis. The mirror from the x-axis and An axial voltage calculating step for calculating axial voltages Vx and Vy that rotate about the axis, and an electrode voltage control step for calculating an electrode voltage to be applied to each electrode from Vx and Vy and applying this electrode voltage to the corresponding electrode The electrodes are composed of electrodes a and b for controlling the rotation of the mirror about the x-axis and electrodes c and d for controlling the rotation of the mirror about the y-axis. Assuming that the electrode voltage applied to the electrode a is Va and the electrode voltage applied to the electrode b is Vb, 2 Vx = Va−Vb, and the voltage Vy is the electrode voltage applied to the electrode c Vc, Assuming that the electrode voltage applied to d is Vd, 2 Vy = Vc−Vd, and the relationship between the shaft voltage Vx and the shaft voltage Vy is Vy = A (Vx−Vx) where the constant is A (≠ 0). ₀₎ is represented by + Vy _0, electrode voltage V , Vb, Vc, is Vd, the bias applied to peak coordinate optical loss is minimized in the Vx-Vy plane (Vx _0, Vy _0), the bias voltage applied to the shaft voltage Vx Vxbias, the axial voltage Vy The voltage is Vybias, the ratio of the voltage that realizes the maximum rotation angle around the x-axis of the mirror and Vxbias is η _x , and the ratio of the voltage that realizes the maximum rotation angle around the y-axis of the mirror and Vybias is η _y Then, when Vx ≧ 0, Va = 2 (1-η _x ) Vx + Vxbias, Vb = −2η _x Vx + Vxbias, and when Vy <0, Va = 2η _x Vx + Vxbias, Vb = −2 (1−η _x ) Vx + Vxbias, when Vy ≧ 0, Vc = 2 ( 1-η y) Vy + Vybias, Vd = -2η y Vy + Vybias, when _{Vy <0, Vc = 2η y} Vy + Vybias, Vd = - It is characterized in that represented by _{(1-η y) Vy +} Vybias.

In the optical switch control method, the relationship between the shaft voltage Vx and the shaft voltage Vy may be expressed as Vy = A (Vx−Vx ₀ ) ^α + Vy ₀ where ^α is an integer equal to or greater than 1. Good.

  In the optical switch control method, the control voltage calculation step acquires a control voltage corresponding to the target optical loss based on the correspondence between the optical loss stored in advance and the control voltage. Also good.

  In the optical switch control method, the control voltage calculation step corresponds to the target light intensity based on an approximate expression of the control voltage that approximates the correspondence between the optical loss and the control voltage stored in advance. The control voltage thus obtained may be acquired.

  According to the present invention, the electrode voltage is calculated from the axial voltage Vx and the voltage Vy based on the relationship between the rotation angle of the mirror when the bias voltage is applied to the electrode and the electrode voltage, and the calculated electrode voltage is associated with the calculated voltage. Crosstalk and Rabbit Ear can be suppressed by rotating the mirror by applying it to the electrodes. Therefore, it is not necessary to use a high-order function that requires a high calculation load and variable accuracy, and an arithmetic unit or the like for performing the calculation is not required. Therefore, crosstalk and Rabbit Ear can be suppressed at a low cost. Can do.

It is a figure which shows typically the structure of the optical switch which concerns on the 1st Embodiment of this invention. It is a figure which shows the locus | trajectory of Vt on a Vx-Vy plane. (A) is principal part sectional drawing of the mirror 1042 which shows the rotation state when the voltage Va is applied, (b) is a figure which shows the V-theta characteristic at the time of (a). (A) is principal part sectional drawing of the mirror 1042 which shows the rotation state when the voltage Vb is applied, (b) is a figure which shows the V-theta characteristic at the time of (a). It is a figure which shows V-theta characteristic when Formula (7), (8) is applied. It is a figure which shows the relationship between the rotation angle (theta) m of the largest mirror, and the voltage Vm which gives this (theta) m. It is a figure which shows VxV-theta characteristic when Formula (11), (12) is applied. It is a figure which shows a Vx-Vy characteristic when a bias voltage is added about the V-theta characteristic of Vx, and a bias voltage is not applied about the V-theta characteristic of Vy. It is a figure which shows the (theta) x-thetay characteristic at the time of FIG. It is a figure for demonstrating the V-theta characteristic when a bias voltage is not applied. It is a figure for demonstrating the V-theta characteristic when a bias voltage is added. It is a figure which shows typically the structure of the optical switch which concerns on the 2nd Embodiment of this invention. It is a figure which shows typically the structure of an Add type | mold wavelength selective switch. It is a figure which shows typically the structure of a Drop type | mold wavelength selective switch. It is the figure which simplified the wavelength selective switch of FIG. (A) is a figure which shows the structure of a mirror, (b) is a figure which shows the structure of a MEMS mirror apparatus, (c) is a figure which shows the rotation of the mirror around the x-axis in a MEMS mirror apparatus, (d) is a MEMS mirror. It is a figure which shows rotation around the y-axis of the mirror in an apparatus. It is a loss contour map in case the peak for N port exists. It is a loss contour map on the Vx-Vy plane. It is a figure which shows the transmittance | permeability of the Vx direction in FIG. 12A. It is a figure which shows the transmittance | permeability of the Vy direction in FIG. 12A. It is a loss contour map on the Vx-Vy plane in the case of switching a rotating shaft. It is a figure which shows the transmittance | permeability and loss of Vt in FIG. 13A. It is a figure which shows the locus | trajectory of Vt on the loss contour line at the time of introduce | transducing a high-order function. It is a figure which shows the transmittance | permeability and loss of Vt in FIG. 20A.

[First Embodiment]
First, a first embodiment of the present invention will be described. The optical switch according to the present embodiment controls the rotation of the mirror of the optical switch by using the characteristics when a bias voltage described later is applied to the mirror, and will be described with reference to FIG. The drive control unit 400 of the optical switch 100 is replaced with a drive control unit 10 described later. Therefore, in the following, the same components and components as those of the optical switch 100 are denoted by the same names and reference numerals, and description thereof will be omitted as appropriate.

<Configuration of optical switch>
As shown in FIG. 1, the optical switch 1 according to the present embodiment includes a spatial optical system switch unit 300 and a drive control unit 10 that controls the operation of the MEMS mirror device 104 included in the spatial optical system switch unit 300. Consists of The drive control unit 10 includes an O / E converter 11 including a photodiode that converts optical power branched from an output port using a coupler 110 into an electrical signal, and the electrical converted by the O / E converter 11. An A / D converter 12 that digitally converts the signal and obtains the value of the light intensity of the optical signal based on the branched optical power, and the light intensity and light intensity of the output light obtained by the A / D converter 12 A comparator 13 for obtaining a difference from the target value (hereinafter referred to as a deviation), a compensation amount calculating unit 14 for obtaining a compensation amount proportional to the deviation, and a compensation amount calculated by the compensation amount calculating unit 14 as a control voltage. An adder 15 for adding negative feedback, a delay device 16 comprising a memory for holding the control voltage with the compensation amount added for the next P control for an arbitrary control period ΔT, and the compensation amount Control voltage from the axis The calculation unit 17 that calculates the pressures Vx and Vy, and the electrode voltages Va, Vb, Vc, and Vd are obtained from the axial voltages Vx and Vy calculated by the calculation unit 17, and the MEMS mirror device 104 of the spatial optical system switch unit 300 determines An electrode voltage control unit 18 to be applied and a timer 19 for executing P control at an arbitrary period ΔT are configured.

  The drive control unit 10 includes a microprocessor such as a CPU / FPGA / ASIC, a control memory, and its peripheral circuits. The drive control unit 10 reads and executes the operation program stored in the control memory, thereby executing the hardware and the operation program. In cooperation, the above-described A / D conversion unit 12, comparator 13, compensation amount calculation unit 14, adder 15, delay unit 16, calculation unit 17, electrode voltage control unit 18, and timer 19 are realized.

  In the present embodiment, when the electrode voltage control unit 18 obtains the electrode voltages Va, Vb, Vc, Vd from the axial voltages Vx, Vy, the mirror voltage against the change in the electrode voltage (V) is determined by the bias voltage applied to the mirror. A change in characteristics related to the change in the rotation angle (θ) (hereinafter referred to as V-θ characteristics) is utilized. This will be described below. The bias voltage means a steady DC component voltage applied to the electrode voltage.

<Calculation principle of electrode voltage>
FIGS. 3A and 3B show the state of the mirror 1041 and the Va-θ characteristics when the electrode voltage Va is applied to the electrode 1042a that causes the x-axis to rotate in the positive direction. In FIGS. 3A and 3B, the values of the other electrode voltages are zero. Similarly, FIGS. 4A and 4B show the state of the mirror and the Vb-θ characteristic when the electrode voltage Vb is applied to the electrode 1042b that causes the x-axis to rotate in the negative direction.
Since the mirror 1041 uses an electrostatic force proportional to the square of the electrode voltage as a main power source for rotation, the V-θ characteristic shows a shape close to a quadratic curve. At this time, the relationship between Va, Vb and Vx in the above formulas (1) and (2) is expressed by the following formulas (7) and (8), so that the V-θ characteristic with respect to the shaft voltage Vx is shown in FIG. Thus, FIG. 3B and FIG. 4B are added together. As shown in FIG. 5, the locus drawn by the relationship between the axial voltage Vx and the rotation angle θ of the mirror 1041 shows a shape close to a quadratic function. In FIG. 5, it can be said that the bias voltage is 0 because there is no steady DC component.

Va = f _{x +} (Vx) = Vx (Vx ≧ 0), Va = f _{x +} (Vx) = 0 (Vx <0)
... (7)
Vb = f _x− (Vx) = 0 (Vx ≧ 0), Vb = f _x− (Vx) = − Vx (Vx <0)
... (8)

  Here, as shown in FIG. 6, when the largest rotation angle of the mirror 1041 is set to θm during use as in the case where the mirror 1041 is tilted toward the port located at the end, the voltage that gives this θm Assume that a half value of Vm is applied to each electrode as a bias voltage Vxb. At this time, the relationship between Va, Vb and Vx in the equation (1) is expressed by the following equations (9) and (10).

Va = f _{x +} (Vx) = Vx + Vxb (9)
Vb = f _x− (Vx) = − Vx + Vxb (10)

  The V-θ characteristic with respect to Vx based on the above equations (9) and (10) is expressed in FIG. As can be seen from FIG. 7, when the half value of the voltage Vm that realizes θm is applied as the bias voltage Vxb, a locus that describes the relationship between the shaft voltage and the rotation angle is greater than when the bias voltage shown in FIG. 5 is not applied. Approaching linearity. Details of the principle approaching this linearity will be described later.

  Thus, the linearity of the V-θ characteristic can be greatly changed by applying the bias voltage. For example, the V-θ characteristic of Vx is made linear by applying a bias voltage, and the V-θ characteristic of Vy is made a quadratic function shape by not applying a bias voltage. In this way, the linear trajectory showing the relationship between Vx and Vy on the axial voltage plane (Vx−Vy) shown in FIG. 8 is two on the angle plane (θx−θy) shown in FIG. A trajectory of the next function will be drawn. That is, by adjusting the bias voltages Vxb and Vyb applied to the axial voltage, a linear trajectory on the axial voltage plane can be changed to a linear function trajectory on the angle plane. As a result, even if complicated high-order functions are not introduced, the same trajectory as when the mirror is rotated with a high-order function on the angle plane can be obtained by appropriately setting a bias voltage that is a DC voltage. As a result, an expensive arithmetic unit that handles a high-order function is not required, so that crosstalk and Rabbit Ear can be suppressed at a low cost.

<Principle of linear approximation by applying bias voltage>
Next, it will be described that the relationship between the electrode voltage and the rotation angle approximates a straight line by applying a bias voltage.

First, the premise will be described. The mirror 1041 determines the rotation angle θ by the balance between the rotational moment due to the electrostatic force between the parallel plate electrodes and the restoring moment of the torsion spring regardless of the presence or absence of the bias voltage. At this time, the electrostatic force dF generated in the minute interval dx between the electrodes is expressed by the following equation (11). In this equation (11), ε ₀ is the dielectric constant, g is the distance between the mirror 1041 and the electrode, and V is the voltage. For the sake of convenience, a model is a uniaxial rotating mirror whose electrode width (depth) is a unit length.

dF = ε ₀ dxV ² / 2g ² (11)

  The restoring moment Msp of the torsion spring is expressed by the following formula (12) by the spring constant Isp.

Msp = Ispθ (12)

  Based on such a premise, first, a case where a bias voltage is not applied will be described with reference to FIG.

  The restoring moment by the spring is expressed by the above equation (11). On the other hand, the moment Mel due to the electrostatic force is expressed by the following expression (13).

  In the above equation (13), the dependence of θ on the voltage V can be obtained by solving for θ with Msp = Mel, but this calculation is complicated. Therefore, the focus is on the vicinity of V = 0, and since it can be considered that θ≈0 in the vicinity of V = 0, θ is eliminated as g−xθ≈g from the above equation (13). As a result, the following equation (14) is derived by providing the above equations (12) and (13) simultaneously.

  Thus, when no bias voltage is applied, the equation (16) indicating the relationship between the electrode voltage V and the rotation angle θ is expressed by a quadratic expression of the rotation angle θ of the electrode voltage V. The mirror 1041 of the optical switch has a rotation angle of about several degrees at the maximum. In the case of a MEMS mirror, L = several hundred μm and g = several tens of μm. As described above, even if g−xθ≈g, a large error does not occur.

  Next, a case where a bias voltage (Vb) is applied will be described with reference to FIG.

  The restoring moment by the torsion spring is expressed by the above equation (12). On the other hand, the moment Mel due to the electrostatic force is expressed by the following equation (15).

In the above equation (15), dF ₊ and dF ₋ are a positive side region (dF ₊ ) and a negative side region (dF) in the X direction when the rotation axis around the y axis of the mirror 1041 is the center. _-) is electrostatic force generated in the minute section. As in the case where no bias voltage is applied, the dependence of θ on the voltage V can be obtained by solving for θ with Msp = Mel, but this calculation is more complicated than when no bias voltage is applied. Here, the focus is also on the vicinity of V = 0, and in the vicinity of V = 0, it can be considered that θ≈0. Therefore, θ is eliminated as g−xθ≈g from the above equation (15), and A ² −B ² = (A + B) The following formula (16) is derived from the formula (A−B).

  By combining the above equation (12) and the above equation (16), the following equation (17) is derived.

  Thus, when the bias voltage is applied, the equation (17) indicating the relationship between the electrode voltage V and the rotation angle θ is expressed by a linear expression of the rotation angle θ of the electrode voltage V.

  As can be seen from the above equations (14) and (17), by applying a bias voltage, the relationship between the electrode voltage and the rotation angle approaches a straight line in the vicinity of V = 0.

<Operation of optical switch>
Next, the operation of the optical switch 1 according to the present embodiment will be described with reference to FIG.

  When the optical signal is branched from the output port by the coupler 10, the optical signal is converted into an electric signal by the O / E converter 11, converted into a digital signal by the A / D converter 12, and the light intensity of the output light. Is calculated.

  When the light intensity of the output light of the optical signal is calculated, the comparator 13 calculates a deviation between the light intensity and the target value of the light intensity of the output light of the optical signal.

  When the deviation is calculated, the compensation amount calculation unit 14 calculates a compensation amount proportional to the deviation. When the output power is smaller than the target value by the deviation e, the compensation amount calculation unit 14 adds a compensation amount Kp times the deviation e to the control voltage. The sign of the compensation amount at the time of addition is a sign that increases the output by adding the compensation amount to the control voltage. By appropriately setting the value of Kp, when there is a deviation e, the control voltage is corrected so as to cancel this deviation e, so that the light intensity of the output light finally approaches the target value.

  When the compensation amount is calculated, the adder 15 adds the compensation amount to the control voltage so as to be negatively fed back. At this time, the delay unit 16 holds the control voltage to which the compensation amount is added for the next P control, and holds it for an arbitrary control period ΔT timed by the timer 19.

When the compensation amount is added to the control voltage, the calculation unit 17 calculates the shaft voltages Vx and Vy from the control voltage. An example of the locus of the axial voltage (Vx, Vy) of the mirror 1041 calculated by the calculation unit 17 is shown in FIG. In the present embodiment, Vt, which is an arbitrary parameter of the shaft voltages Vx and Vy, is employed as the control voltage. The locus drawn by Vt is inclined by φ with respect to the Vy axis, as shown in FIG. This Vt represents the distance from the origin on the axis with (Vx ₀ , Vy ₀ ) as the origin, and is represented by the following equations (20) and (21). In the following formulas (20) and (21), A in the above formulas (3) to (6) corresponds to cos φ, and B corresponds to sin φ.

Vx = Vtcosφ + Vx ₀ (20)
Vy = Vtsinφ + Vy ₀ (21)

  In FIG. 2, the sign of Vt can be defined by the direction of the axis. In the case of FIG. 2, the upper right of the paper is the positive direction of Vt, but depending on the setting of φ, various directions can be the positive direction of Vt.

  When the axial voltages Vx and Vy are calculated from the control voltage Vt, the electrode voltage control unit 18 applies the electrode voltages to the electrodes 1042a to 1042d in the MEMS mirror device 104 of the spatial optical system switch unit 300 from the axial voltages Vx and Vy. Va, Vb, Vc, and Vd are calculated. A method for calculating the electrode voltages (Va, Vb, Vc, Vd) from the axial voltages (Vx, Vy) in the electrode voltage calculation unit 18 will be described below.

  As described above, this embodiment is characterized in that the locus on the angle plane is changed by applying a bias voltage, and the bias voltage is set to an arbitrary value between 0 and Vm. It is assumed that. For this reason, the calculation formula of the electrode voltage is defined so that the electrode voltage does not become a negative voltage even if the bias voltage is arbitrarily changed. This is because it is assumed that the mirror 1041 is controlled with a unipolar voltage.

The calculation formulas from the axial voltages (Vx, Vy) to the electrode voltages (Va, Vb, Vc, Vd) shown in the above formulas (1) and (2) are as follows for Vx when Vx ≧ 0 : ), (23), when Vx <0, the following formulas (26), (27) are expressed. When Vy ≧ 0, Vy is expressed by the following formulas (24), (25), and when Vy <0, the following formulas are expressed: (28), (29). Vxbias is a bias voltage applied to the axis voltage Vx, that is, a bias voltage that affects the rotation of the mirror 1041 around the x axis. Similarly, Vybias is a bias voltage applied to the axis voltage Vy, that is, a bias voltage that affects the rotation of the mirror 1041 around the y axis.

Va = f _{x +} (Vx) = 2 (1−η _x ) Vx + Vxbias (22)
Vb = f _x− (Vx) = − 2η _x Vx + Vxbias (23)
Vc = f _{y +} (Vy) = 2 (1−η _y ) Vy + Vybias (24)
Vd = f _y− (Vy) = − 2η _y Vy + Vybias (25)

Va = f _{x +} (Vx) = 2η _x Vx + Vxbias (26)
Vb = f _x− (Vx) = − 2 (1−η _x ) Vx + Vxbias (27)
Vc = f _{y +} (Vy) = 2η _y Vy + Vybias (28)
_{Vd = f y- (Vy) =} - 2 (1-η y) Vy + Vybias ··· (29)

  Here, η is a value indicating the ratio of the bias voltage Vbias to the voltage Vm giving the maximum angle θm, as shown in the following equation (30), and is a value in the range of 0-1. Changing the bias voltage means changing η. This η is calculated for each of the x-axis and the y-axis as shown in the following equations (31) and (32). Here, Vxm represents an axial voltage when the maximum angle θxm around the x axis of the mirror 1041 is realized, and Vym represents an axial voltage when the maximum angle θym around the y axis of the mirror 1041 is realized.

η = Vbias / Vm (30)
η _x = Vxbias / Vxm (31)
η _y = Vybias / Vym (32)

  The bias voltage is an arbitrary value, but is not a value that dynamically changes during the operation of the optical switch. Therefore, by checking the voltage Vm of each axis from the V-θ characteristics in advance and determining η from this, the values of (1-η), Vxbias, and Vybias become constants. The variable of (29) is only the shaft voltages Vx and Vy. The constant term may be calculated from η given in advance each time it is calculated, or a value calculated in advance may be stored in the memory of the control circuit, and the value of the memory may be referred to when necessary. .

  In this way, when the electrode voltage is calculated using the above equations (22) to (29), the electrode voltage control unit 18 applies the electrode voltage to the corresponding electrodes 1042a to 1042d. As a result, the mirror 1041 having the two rotational axes of the MEMS mirror device 104 can be controlled without performing complicated calculations, so that the cost can be reduced and the crosstalk can be reduced and the Rabbit Ear can be suppressed. Can be realized seamlessly and continuously without changing the direction of the mirror suddenly.

  As described above, according to the present embodiment, the calculation unit 17 calculates the shaft voltages Vx and Vy for rotating the mirror 1041 around the x axis and the y axis by a predetermined amount from the control voltage Vt. The electrode voltage controller 18 calculates the electrode voltage applied to each electrode from the axial voltages Vx and Vy based on the relationship between the rotation angle of the mirror when the bias voltage is applied to the electrode and the electrode voltage. Even without using high-order functions that require high computational load and variable accuracy, mirror operation that achieves both crosstalk reduction and Rabbit Ear suppression can be performed seamlessly without changing the mirror direction suddenly. Can be realized continuously. As a result, it is possible to reduce crosstalk and suppress Rabbit Ear at a lower cost.

  In the present embodiment, the Vx characteristic of Vx is made linear by applying a bias voltage, and the Vy characteristic of Vy is made a quadratic function shape by not applying a bias voltage. However, Vx and Vy may be reversed.

  Needless to say, the present embodiment can also be applied to I control and D control of PID control.

[Second Embodiment]
Next, a second embodiment according to the present invention will be described. The present embodiment does not have a mirror rotation control function based on negative feedback control, and other configurations are the same as those of the first embodiment described above. Therefore, in the present embodiment, the same names and symbols are assigned to the same components as those in the first embodiment described above, and the description thereof is omitted as appropriate.

  As shown in FIG. 12, the optical switch 2 according to the present embodiment includes a spatial optical system switch unit 300 and a drive control unit 20 that controls the operation of the MEMS mirror device 104 included in the spatial optical system switch unit 300. Consists of The drive control unit 20 includes a control voltage calculation unit 21, a calculation unit 17, and an electrode voltage control unit 18.

  Here, the control voltage calculation unit 21 includes a data table storing the value of the control voltage with respect to the optical loss, or an approximate expression including a higher-order other-order expression of the control voltage representing the relationship between the optical loss and the control voltage. The control voltage is calculated based on the target value of the optical loss.

  As described above, when the control voltage is calculated by the control voltage calculation unit 21, the calculation unit 17 calculates the control voltage based on the above equations (20) and (21) as in the first embodiment. From these, the shaft voltages Vx and Vy are calculated. When the axial voltages Vx and Vy are calculated, the electrode voltage control unit 18 calculates the MEMS mirror device 104 of the spatial optical system switch unit 300 from the axial voltages Vx and Vy based on the above equations (22) to (29). Electrode voltages Va, Vb, Vc, and Vd applied to the electrodes 1042a to 1042d are calculated and applied to the corresponding electrodes 1042a to 1042d. Thereby, the loss of the optical signal which has a wavelength corresponding to a mirror can be made into a predetermined range.

  Thus, according to the present embodiment, the control voltage calculation unit 21 calculates the control voltage corresponding to the target light loss, and the calculation unit 17 moves the mirror 1041 from the control voltage to the x axis and the y axis. Axial voltages Vx and Vy that are respectively rotated around the axis are calculated, and the electrode voltage control unit 18 calculates the axis voltages Vx and Vx based on the relationship between the rotation angle of the mirror and the electrode voltage when a bias voltage is applied to the electrodes. By calculating the electrode voltage to be applied to each electrode from Vy and applying it to the corresponding electrode, crosstalk can be reduced and Rabbit Ear can be reduced without using a high-order function that requires high calculation load and variable accuracy. The operation of the mirror that achieves both suppression can be realized seamlessly and continuously without abruptly changing the mirror direction on the way. As a result, it is possible to reduce crosstalk and suppress Rabbit Ear at a lower cost.

  In the first and second embodiments described above, the case of an Add type wavelength selective switch has been described as an example, but the present invention can also be applied to a Drop type wavelength selective switch as shown in FIG.

  The present invention can be applied to various devices that control the rotation of a reflecting member that can rotate around two axes, such as a MEMS mirror device.

  DESCRIPTION OF SYMBOLS 1, 2 ... Optical switch 10, 20 ... Drive control part, 11 ... O / E converter, 12 ... A / D converter, 13 ... Comparator, 14 ... Compensation amount calculation part, 15 ... Adder, 16 ... Delay unit, 17 ... calculation unit, 18 ... electrode voltage control unit, 19 ... timer, 21 ... control voltage calculation unit, 101, 101-1 to 101-n ... input side optical fiber, 102, 102-1 to 102-n DESCRIPTION OF SYMBOLS ... Output side optical fiber, 103 ... Diffraction grating, 104 ... MEMS mirror apparatus, 105 ... Demultiplexer, 106-1 to 106-m ... Photodiode, 107 ... A / D converter. DESCRIPTION OF SYMBOLS 108 ... Mirror control circuit, 109 ... Merger, 110 ... Coupler, 300 ... Spatial optical system switch part, 1041 ... Mirror, 1042a-1042d ... Electrode.

Claims (16)

At least one light input section for inputting input light;
At least one light output unit for outputting output light;
A mirror supported to be rotatable with respect to an x-axis used for selecting the light input unit or the light output unit and a y-axis orthogonal to the x-axis, and a plurality of electrodes arranged to face the mirror A mirror device having
A drive control unit that applies an electrode voltage to the electrode to rotate the mirror about the x axis and the y axis; and
An optical switch comprising: a detection unit that detects light intensity of output light output from the light output unit;
The drive control unit
A control voltage calculation unit for calculating a control voltage corresponding to the target light intensity;
An axis voltage calculation unit for calculating axis voltages Vx and Vy for rotating the mirror about the x axis and the y axis, respectively, from the control voltage;
The rotation angle and electrode voltage of the mirror when the bias voltage Vxbias is applied to the electrode for rotating the mirror about the x-axis and the bias voltage Vybias is applied to the electrode for rotating the mirror about the y-axis, respectively. An electrode voltage applied to each of the electrodes from the Vx and the Vy, and an electrode voltage controller that applies the electrode voltage to the corresponding electrode;
A comparison unit for obtaining a deviation between the detection result detected by the detection unit and the target light intensity;
An optical switch comprising: a compensation unit that adds a compensation amount according to a deviation output from the comparison unit to the control voltage, and negatively feeds back the deviation to the control voltage. At least one light input section for inputting input light;
At least one light output unit for outputting output light;
A mirror supported to be rotatable with respect to an x-axis used for selecting the light input unit or the light output unit and a y-axis orthogonal to the x-axis, and a plurality of electrodes arranged to face the mirror A mirror device having
A drive control unit that applies an electrode voltage to the electrode to rotate the mirror about the x axis and the y axis; and
An optical switch comprising: a detection unit that detects light intensity of output light output from the light output unit;
The drive control unit
A control voltage calculation unit for calculating a control voltage corresponding to the target light intensity;
An axis voltage calculation unit for calculating axis voltages Vx and Vy for rotating the mirror about the x axis and the y axis, respectively, from the control voltage;
An electrode voltage controller for calculating an electrode voltage to be applied to each of the electrodes from the Vx and the Vy, and applying the electrode voltage to the corresponding electrode;
A comparison unit for obtaining a deviation between the detection result detected by the detection unit and the target light intensity;
A compensation unit that adds a compensation amount according to the deviation output from the comparison unit to the control voltage, and negatively feeds back the deviation to the control voltage.
The electrodes include electrodes a and b for controlling the rotation of the mirror about the x-axis and electrodes c and d for controlling the rotation of the mirror about the y-axis,
In the electrode voltage control means,
The axial voltage Vx is expressed as 2 Vx = Va−Vb, where Va is an electrode voltage applied to the electrode a, and Vb is an electrode voltage applied to the electrode b.
The axial voltage Vy is expressed as 2 Vy = Vc−Vd, where Vc is an electrode voltage applied to the electrode c, and Vd is an electrode voltage applied to the electrode d.
The relationship between the shaft voltage Vx and the shaft voltage Vy is expressed as Vy = A (Vx−Vx ₀ ) + Vy ₀ where A (≠ 0) is a constant.
The electrode voltages Va, Vb, Vc, and Vd are coordinates (Vx ₀ , Vy ₀ ) at which the light loss is minimized on the Vx-Vy plane, Vxbias is the bias voltage applied to the axis voltage Vx, and the axis The bias voltage applied to the voltage Vy is Vybias, the ratio of the voltage that realizes the maximum rotation angle of the mirror about the x axis and the Vxbias is η _x , and the maximum rotation angle of the mirror about the y axis is realized If the ratio of the voltage to be used and Vybias is η _y ,
When Vx ≧ 0,
Va = 2 (1-η _x ) Vx + Vxbias
Vb = -2η _x Vx + Vxbias
When Vx <0,
Va = 2η _x Vx + Vxbias
Vb = -2 (1-η _x ) Vx + Vxbias
When Vy ≧ 0,
Vc = 2 (1-η _y ) Vy + Vybias
Vd = -2η _y Vy + Vybias
When Vy <0,
Vc = 2η _y Vy + Vybias
Vd = -2 (1- [eta] _y ) Vy + Vybias
An optical switch characterized by the following: At least one light input section for inputting input light;
At least one light output unit for outputting output light;
A mirror supported to be rotatable with respect to an x-axis used for selecting the light input unit or the light output unit and a y-axis orthogonal to the x-axis, and a plurality of electrodes arranged to face the mirror A mirror device having
A drive control unit that applies an electrode voltage to the electrode to rotate the mirror about the x axis and the y axis; and
A detection unit for detecting the light intensity of the output light output from the light output unit;
A demultiplexing unit for demultiplexing the output light detected by the detection unit for each wavelength,
The drive control unit
A photoelectric conversion unit that converts the output light demultiplexed by the demultiplexing unit into an electrical signal;
An A / D converter that digitally converts the electrical signal and outputs a value of the optical power of the output light;
A comparison unit for obtaining a deviation between a value of the light intensity of the output light and a target value of the light intensity;
A compensation amount calculation unit for obtaining a compensation amount proportional to the deviation output from the comparison unit;
An adding unit for adding the compensation amount to the control voltage so as to be negatively fed back;
A delay unit for holding the control voltage to which the compensation amount is added for an arbitrary control period;
An axial voltage calculation unit for calculating axial voltages Vx and Vy for rotating the mirror about the x-axis and the y-axis, respectively, from the control voltage to which the compensation amount is added;
An electrode voltage to be applied to each of the electrodes from the Vx and the Vy, and an electrode voltage control unit to apply the electrode voltage to the corresponding electrode, and
The electrodes include electrodes a and b for controlling the rotation of the mirror about the x-axis and electrodes c and d for controlling the rotation of the mirror about the y-axis,
In the electrode voltage control means,
The axial voltage Vx is expressed as 2 Vx = Va−Vb, where Va is an electrode voltage applied to the electrode a, and Vb is an electrode voltage applied to the electrode b.
The axial voltage Vy is expressed as 2 Vy = Vc−Vd, where Vc is an electrode voltage applied to the electrode c, and Vd is an electrode voltage applied to the electrode d.
The relationship between the shaft voltage Vx and the shaft voltage Vy is expressed as Vy = A (Vx−Vx ₀ ) + Vy ₀ where A (≠ 0) is a constant.
The electrode voltages Va, Vb, Vc, and Vd are coordinates (Vx ₀ , Vy ₀ ) at which the light loss is minimized on the Vx-Vy plane, Vxbias as the bias voltage applied to the axis voltage Vx, and the axis voltage. The bias voltage applied to Vy is Vybias, the ratio of the voltage that realizes the maximum rotation angle of the mirror around the x-axis to the Vxbias is η _x , and the voltage that realizes the maximum rotation angle of the mirror around the y-axis. And the ratio of Vybias to η _y ,
When Vx ≧ 0,
Va = 2 (1-η _x ) Vx + Vxbias
Vb = -2η _x Vx + Vxbias
When Vx <0,
Va = 2η _x Vx + Vxbias
Vb = -2 (1-η _x ) Vx + Vxbias
When Vy ≧ 0,
Vc = 2 (1-η _y ) Vy + Vybias
Vd = -2η _y Vy + Vybias
When Vy <0,
Vc = 2η _y Vy + Vybias
Vd = -2 (1- [eta] _y ) Vy + Vybias
An optical switch characterized by the following: At least one light input section for inputting input light;
At least one light output unit for outputting output light;
A mirror supported to be rotatable with respect to an x-axis used for selecting the light input unit or the light output unit and a y-axis orthogonal to the x-axis, and a plurality of electrodes arranged to face the mirror A mirror device having
A drive control unit that applies an electrode voltage to the electrode to rotate the mirror about the x-axis and the y-axis, respectively.
The drive control unit
A control voltage calculation unit for calculating a control voltage corresponding to the target optical loss;
An axis voltage calculation unit for calculating axis voltages Vx and Vy for rotating the mirror about the x axis and the y axis, respectively, from the control voltage;
The rotation angle and electrode voltage of the mirror when the bias voltage Vxbias is applied to the electrode for rotating the mirror about the x-axis and the bias voltage Vybias is applied to the electrode for rotating the mirror about the y-axis, respectively. And an electrode voltage control unit for calculating an electrode voltage to be applied to each of the electrodes from the Vx and the Vy, and applying the electrode voltage to the corresponding electrode. . At least one light input section for inputting input light;
At least one light output unit for outputting output light;
A mirror supported to be rotatable with respect to an x-axis used for selecting the light input unit or the light output unit and a y-axis orthogonal to the x-axis, and a plurality of electrodes arranged to face the mirror A mirror device having
A drive control unit that applies an electrode voltage to the electrode to rotate the mirror about the x-axis and the y-axis, respectively.
The drive control unit
A control voltage calculation unit for calculating a control voltage corresponding to the target optical loss;
An axis voltage calculation unit for calculating axis voltages Vx and Vy for rotating the mirror about the x axis and the y axis, respectively, from the control voltage;
An electrode voltage to be applied to each of the electrodes from the Vx and the Vy, and an electrode voltage control unit to apply the electrode voltage to the corresponding electrode, and
The electrodes include electrodes a and b for controlling the rotation of the mirror about the x-axis and electrodes c and d for controlling the rotation of the mirror about the y-axis,
In the electrode voltage control means,
The axial voltage Vx is expressed as 2 Vx = Va−Vb, where Va is an electrode voltage applied to the electrode a, and Vb is an electrode voltage applied to the electrode b.
The axial voltage Vy is expressed as 2 Vy = Vc−Vd, where Vc is an electrode voltage applied to the electrode c, and Vd is an electrode voltage applied to the electrode d.
The relationship between the shaft voltage Vx and the shaft voltage Vy is expressed as Vy = A (Vx−Vx ₀ ) + Vy ₀ where A (≠ 0) is a constant.
The electrode voltages Va, Vb, Vc, and Vd are coordinates (Vx ₀ , Vy ₀ ) at which the light loss is minimized on the Vx-Vy plane, Vxbias is the bias voltage applied to the axis voltage Vx, and the axis The bias voltage applied to the voltage Vy is Vybias, the ratio of the voltage that realizes the maximum rotation angle of the mirror about the x axis and the Vxbias is η _x , and the maximum rotation angle of the mirror about the y axis is realized If the ratio of the voltage to be used and Vybias is η _y ,
When Vx ≧ 0,
Va = 2 (1-η _x ) Vx + Vxbias
Vb = -2η _x Vx + Vxbias
When Vx <0,
Va = 2η _x Vx + Vxbias
Vb = -2 (1-η _x ) Vx + Vxbias
When Vy ≧ 0,
Vc = 2 (1-η _y ) Vy + Vybias
Vd = -2η _y Vy + Vybias
When Vy <0,
Vc = 2η _y Vy + Vybias
Vd = -2 (1- [eta] _y ) Vy + Vybias
An optical switch characterized by the following: In any one of Claims 2, 3, and 5,
The relationship between the shaft voltage Vx and the shaft voltage Vy is expressed by Vy = A (Vx−Vx ₀ ) ^α + Vy ₀ where ^α is an integer equal to or greater than 1. The optical switch according to claim 4 or 5,
A storage unit that stores in advance the correspondence between the optical loss and the control voltage;
The optical switch, wherein the control voltage calculation unit acquires a control voltage corresponding to the target optical loss from the storage unit. The optical switch according to claim 4 or 5,
A storage unit that stores in advance an approximate expression of the control voltage that approximates the correspondence between the optical loss and the control voltage;
The control voltage calculation unit acquires a control voltage corresponding to the target optical loss based on the approximate expression stored in the storage unit. At least one light input section for inputting input light;
At least one light output unit for outputting output light;
A mirror supported to be rotatable with respect to an x-axis used for selecting the light input unit or the light output unit and a y-axis orthogonal to the x-axis, and a plurality of electrodes arranged to face the mirror A mirror device having
A drive control unit that applies an electrode voltage to the electrode to rotate the mirror about the x axis and the y axis; and
A method of controlling an optical switch comprising: a detection unit that detects the light intensity of output light output from the light output unit;
A control voltage calculating step for calculating a control voltage corresponding to the target light intensity;
An axial voltage calculating step of calculating axial voltages Vx and Vy for rotating the mirror about the x axis and the y axis, respectively, from the control voltage;
The rotation angle and electrode voltage of the mirror when the bias voltage Vxbias is applied to the electrode for rotating the mirror about the x-axis and the bias voltage Vybias is applied to the electrode for rotating the mirror about the y-axis, respectively. An electrode voltage to be applied to each of the electrodes from the Vx and the Vy, and an electrode voltage control step of applying the electrode voltage to the corresponding electrode;
A comparison step for obtaining a deviation of the detection result detected by the detection unit from the target light intensity;
And a compensation step of adding a compensation amount according to the deviation obtained in the comparison step to the control voltage and negatively feeding back the deviation to the control voltage. At least one light input section for inputting input light;
At least one light output unit for outputting output light;
A mirror supported to be rotatable with respect to an x-axis used for selecting the light input unit or the light output unit and a y-axis orthogonal to the x-axis, and a plurality of electrodes arranged to face the mirror A mirror device having
A drive control unit that applies an electrode voltage to the electrode to rotate the mirror about the x axis and the y axis; and
A method of controlling an optical switch comprising: a detection unit that detects the light intensity of output light output from the light output unit;
A control voltage calculating step for calculating a control voltage corresponding to the target light intensity;
An axial voltage calculating step of calculating axial voltages Vx and Vy for rotating the mirror about the x axis and the y axis, respectively, from the control voltage;
An electrode voltage control step of calculating an electrode voltage to be applied to each of the electrodes from the Vx and the Vy, and applying this electrode voltage to the corresponding electrode;
A comparison step for obtaining a deviation between the detection result detected by the detection unit and the target light intensity;
A compensation step of adding a compensation amount according to the deviation obtained by the comparison step to the control voltage, and negatively feeding back the deviation to the control voltage,
The electrodes are composed of electrodes a and b for controlling the rotation of the mirror about the x-axis and electrodes c and d for controlling the rotation of the mirror about the y-axis,
The axial voltage Vx is expressed as 2 Vx = Va−Vb, where Va is an electrode voltage applied to the electrode a, and Vb is an electrode voltage applied to the electrode b.
The axial voltage Vy is expressed as 2 Vy = Vc−Vd, where Vc is an electrode voltage applied to the electrode c, and Vd is an electrode voltage applied to the electrode d.
The relationship between the shaft voltage Vx and the shaft voltage Vy is expressed as Vy = A (Vx−Vx ₀ ) + Vy ₀ where A (≠ 0) is a constant.
The electrode voltages Va, Vb, Vc, and Vd are coordinates (Vx ₀ , Vy ₀ ) at which the light loss is minimized on the Vx-Vy plane, Vxbias is the bias voltage applied to the axis voltage Vx, and the axis The bias voltage applied to the voltage Vy is Vybias, the ratio of the voltage that realizes the maximum rotation angle of the mirror about the x axis and the Vxbias is η _x , and the maximum rotation angle of the mirror about the y axis is realized If the ratio of the voltage to be used and Vybias is η _y ,
When Vx ≧ 0,
Va = 2 (1-η _x ) Vx + Vxbias
Vb = -2η _x Vx + Vxbias
When Vx <0,
Va = 2η _x Vx + Vxbias
Vb = -2 (1-η _x ) Vx + Vxbias
When Vy ≧ 0,
Vc = 2 (1-η _y ) Vy + Vybias
Vd = -2η _y Vy + Vybias
When Vy <0,
Vc = 2η _y Vy + Vybias
Vd = -2 (1- [eta] _y ) Vy + Vybias
An optical switch control method characterized by the following: At least one light input section for inputting input light;
At least one light output unit for outputting output light;
A mirror supported to be rotatable with respect to an x-axis used for selecting the light input unit or the light output unit and a y-axis orthogonal to the x-axis, and a plurality of electrodes arranged to face the mirror A mirror device having
A drive control unit that applies an electrode voltage to the electrode to rotate the mirror about the x axis and the y axis; and
A detection unit for detecting the light intensity of the output light output from the light output unit;
And a demultiplexing unit that demultiplexes the output light detected by the detection unit for each wavelength.
A photoelectric conversion step of converting the output light demultiplexed by the demultiplexing unit into an electrical signal;
An A / D conversion step of digitally converting the electrical signal and outputting a value of optical power of the output light;
A comparison step for obtaining a deviation between a light intensity value of the output light and a target value of the light intensity;
A compensation amount calculating step for obtaining a compensation amount proportional to the deviation output from the comparison unit;
An adding step of adding the compensation amount to the control voltage so as to be negatively fed back;
A delay step of holding the control voltage to which the compensation amount is added for an arbitrary control period;
An axial voltage calculating step of calculating axial voltages Vx and Vy for rotating the mirror about the x-axis and the y-axis, respectively, from the control voltage to which the compensation amount is added;
Calculating an electrode voltage to be applied to each of the electrodes from the Vx and the Vy, and an electrode voltage control step of applying the electrode voltage to the corresponding electrode,
The electrodes are composed of electrodes a and b for controlling the rotation of the mirror about the x-axis and electrodes c and d for controlling the rotation of the mirror about the y-axis,
The axial voltage Vx is expressed as 2 Vx = Va−Vb, where Va is an electrode voltage applied to the electrode a, and Vb is an electrode voltage applied to the electrode b.
The axial voltage Vy is expressed as 2 Vy = Vc−Vd, where Vc is an electrode voltage applied to the electrode c, and Vd is an electrode voltage applied to the electrode d.
The relationship between the shaft voltage Vx and the shaft voltage Vy is expressed as Vy = A (Vx−Vx ₀ ) + Vy ₀ where A (≠ 0) is a constant.
The electrode voltages Va, Vb, Vc, and Vd are coordinates (Vx ₀ , Vy ₀ ) at which the light loss is minimized on the Vx-Vy plane, Vxbias is the bias voltage applied to the axis voltage Vx, and the axis The bias voltage applied to the voltage Vy is Vybias, the ratio of the voltage that realizes the maximum rotation angle of the mirror about the x axis and the Vxbias is η _x , and the maximum rotation angle of the mirror about the y axis is realized If the ratio of the voltage to be used and Vybias is η _y ,
When Vx ≧ 0,
Va = 2 (1-η _x ) Vx + Vxbias
Vb = -2η _x Vx + Vxbias
When Vy <0,
Va = 2η _x Vx + Vxbias
Vb = -2 (1-η _x ) Vx + Vxbias
When Vy ≧ 0,
Vc = 2 (1-η _y ) Vy + Vybias
Vd = -2η _y Vy + Vybias
When Vy <0,
Vc = 2η _y Vy + Vybias
Vd = -2 (1- [eta] _y ) Vy + Vybias
An optical switch control method characterized by the following: At least one light input section for inputting input light;
At least one light output unit for outputting output light;
A mirror supported to be rotatable with respect to an x-axis used for selecting the light input unit or the light output unit and a y-axis orthogonal to the x-axis, and a plurality of electrodes arranged to face the mirror A mirror device having
A drive control unit that applies an electrode voltage to the electrode to rotate the mirror about the x-axis and the y-axis, respectively.
A control voltage calculating step for calculating a control voltage corresponding to the target optical loss;
An axial voltage calculating step of calculating axial voltages Vx and Vy for rotating the mirror about the x axis and the y axis, respectively, from the control voltage;
The rotation angle and electrode voltage of the mirror when the bias voltage Vxbias is applied to the electrode for rotating the mirror about the x-axis and the bias voltage Vybias is applied to the electrode for rotating the mirror about the y-axis, respectively. And an electrode voltage control step of calculating an electrode voltage to be applied to each of the electrodes from the Vx and the Vy, and applying the electrode voltage to the corresponding electrode. Control method. At least one light input section for inputting input light;
At least one light output unit for outputting output light;
A mirror supported to be rotatable with respect to an x-axis used for selecting the light input unit or the light output unit and a y-axis orthogonal to the x-axis, and a plurality of electrodes arranged to face the mirror A mirror device having
A drive control unit that applies an electrode voltage to the electrode to rotate the mirror about the x-axis and the y-axis, respectively.
A control voltage calculating step for calculating a control voltage corresponding to the target optical loss;
An axial voltage calculating step of calculating axial voltages Vx and Vy for rotating the mirror about the x axis and the y axis, respectively, from the control voltage;
Calculating an electrode voltage to be applied to each of the electrodes from the Vx and the Vy, and an electrode voltage control step of applying the electrode voltage to the corresponding electrode,
The electrodes are composed of electrodes a and b for controlling the rotation of the mirror about the x-axis and electrodes c and d for controlling the rotation of the mirror about the y-axis,
The axial voltage Vx is expressed as 2 Vx = Va−Vb, where Va is an electrode voltage applied to the electrode a, and Vb is an electrode voltage applied to the electrode b.
The axial voltage Vy is expressed as 2 Vy = Vc−Vd, where Vc is an electrode voltage applied to the electrode c, and Vd is an electrode voltage applied to the electrode d.
The relationship between the shaft voltage Vx and the shaft voltage Vy is expressed as Vy = A (Vx−Vx ₀ ) + Vy ₀ where A (≠ 0) is a constant.
The electrode voltages Va, Vb, Vc, and Vd are coordinates (Vx ₀ , Vy ₀ ) at which the light loss is minimized on the Vx-Vy plane, Vxbias is the bias voltage applied to the axis voltage Vx, and the axis The bias voltage applied to the voltage Vy is Vybias, the ratio of the voltage that realizes the maximum rotation angle of the mirror about the x axis and the Vxbias is η _x , and the maximum rotation angle of the mirror about the y axis is realized If the ratio of the voltage to be used and Vybias is η _y ,
When Vx ≧ 0,
Va = 2 (1-η _x ) Vx + Vxbias
Vb = -2η _x Vx + Vxbias
When Vy <0,
Va = 2η _x Vx + Vxbias
Vb = -2 (1-η _x ) Vx + Vxbias
When Vy ≧ 0,
Vc = 2 (1-η _y ) Vy + Vybias
Vd = -2η _y Vy + Vybias
When Vy <0,
Vc = 2η _y Vy + Vybias
Vd = -2 (1- [eta] _y ) Vy + Vybias
An optical switch control method characterized by the following: In the control method of the optical switch according to any one of claims 10, 11, and 13,
The relationship between the shaft voltage Vx and the shaft voltage Vy is expressed as Vy = A (Vx−Vx ₀ ) ^α + Vy _0, where ^α is an integer equal to or greater than 1. In the control method of the optical switch according to claim 12 or 13,
The control voltage calculation step includes acquiring a control voltage corresponding to the target optical loss based on the correspondence between the optical loss and the control voltage stored in advance. In the control method of the optical switch according to claim 12 or 13,
The control voltage calculating step obtains a control voltage corresponding to the target light intensity based on an approximate expression of the control voltage approximating the correspondence between the optical loss and the control voltage stored in advance. A method for controlling an optical switch.

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