JP5041417B2 - Optical device device - Google Patents

Description

  The present invention relates to an optical device control apparatus that controls an optical device using a digital pulse signal.

  Conventionally, a technique using a digital pulse signal when controlling a variable optical attenuator (VOA) which is an optical device has been disclosed (see Patent Document 1). In this technique, a part of the optical signal output from the VOA is branched, the intensity of the branched optical signal is converted into an electric signal, and the converted electric signal is detected by an analog-digital converter (ADC). It is converted into a digital pulse signal representing the value and output to the digital processing unit. The digital processing unit calculates a control value for controlling the intensity of the optical signal output from the VOA to a desired value based on the input digital pulse signal and the control target value, and the digital pulse representing the control value The signal is output to a digital-to-analog converter (DAC). Then, the DAC converts the input digital pulse signal into an analog signal and outputs it to the VOA driving circuit. The drive circuit applies a drive voltage generated by amplifying the input analog signal to the VOA. As a result, the intensity of the optical signal output from the VOA is controlled to a desired value.

JP 2007-94395 A

  However, in the above technique, since a plurality of devices that handle digital pulse signals are used, there is a problem that cost reduction, power saving, and size reduction are difficult. In particular, as the number of optical devices to be controlled increases with the increase in the speed and capacity of the optical transmission system, the number of necessary devices also increases. Therefore, the cost of the control device increases, the power consumption increases, and the size increases. There was a problem of becoming.

  The present invention has been made in view of the above, and an object of the present invention is to provide an optical device control apparatus that realizes cost reduction, power saving, and miniaturization.

  In order to solve the above-described problems and achieve the object, an optical device control apparatus according to the present invention generates a digital pulse control signal representing a control value for an optical device to be controlled based on a control target value. A digital processing means for outputting; and a low-pass filter having a band equal to or higher than that of the optical device, accepting the input of the digital pulse control signal, smoothing and amplifying the digital pulse control signal, and Drive means for generating and outputting an analog drive signal for driving the device.

  The optical device control apparatus according to the present invention includes, in the above-described invention, a detection unit that detects a characteristic of the optical device, and an AD conversion unit that performs AD conversion on the detected value of the detected characteristic. The means receives the input of the converted detection value, and generates and outputs a digital pulse control signal representing the control value based on the detection value and the control target value.

  In the optical device control apparatus according to the present invention as set forth in the invention described above, the repetition period of the digital pulse control signal is 1/100 or less of the time constant of the optical device.

  In the optical device control apparatus according to the present invention as set forth in the invention described above, the band of the driving means is 100 times or less the band of the optical device.

  In the optical device control apparatus according to the present invention as set forth in the invention described above, the low-pass filter provided in the driving means is an active filter provided with an operational amplifier.

  According to the present invention, the driving means for driving the optical device includes a low-pass filter having a band that is equal to or higher than the band of the optical device to be controlled, and smoothes and amplifies the digital pulse control signal. Since the analog drive signal to be driven is generated and output, the DAC that has been necessary in the past can be omitted, so that it is possible to realize a control device for an optical device that is reduced in cost, power consumption, and size. Play.

  Embodiments of an optical device control apparatus according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a block diagram of an optical device control apparatus according to Embodiment 1 of the present invention. As shown in FIG. 1, this optical device control device 10 (hereinafter referred to as control device 10) controls a VOA 101 inserted in an optical fiber F that transmits an optical signal. The VOA 101 is, for example, a Maha-Zehnder type similar to that described in Patent Document 1, and the amount of attenuation is changed by changing the temperature of the heater provided therein. The VOA 101 responds to a change in the heater drive voltage with a time constant of several μs to several tens of ms. In the following description, the time constant of the VOA 101 is 3 ms.

  The control device 10 includes optical couplers 11a and 11b, PD monitors 12a and 12b, ADCs 13a and 13b, a digital processing unit 14, and a drive circuit 15. The optical coupler 11a is inserted into the optical fiber F on the optical input side of the VOA 101, and branches a part of the optical signal input to the VOA 101 with a branching ratio of about 1:10 to 100. The PD monitor 12a includes a photodetector (PD) and a logarithmic amplifier, receives a part of the optical signal branched by the optical coupler 11a, converts it into an electrical signal, amplifies it, and responds to the detected value of the optical signal input to the VOA 101. Output electrical signals. The ADC 13 a converts the electrical signal output from the PD monitor 12 a into a digital signal and outputs the digital signal to the digital processing unit 14.

  The VOA 101 attenuates the intensity of the input optical signal and outputs it. The optical coupler 11b is inserted into the optical fiber F on the optical output side of the VOA 101, and branches a part of the attenuated optical signal output from the VOA 101 at a branching ratio of about 1:10 to 100. The PD monitor 12b receives a part of the optical signal branched by the optical coupler 11b, converts it into an electrical signal, amplifies it, and outputs an electrical signal corresponding to the detected value of the optical signal output from the VOA 101. The ADC 13 b converts the electrical signal output from the PD monitor 12 b into a digital signal and outputs the digital signal to the digital processing unit 14.

  The digital processing unit 14 is configured by an FPGA (Field Programmable Gate Array) as an example, and operates at a reference clock frequency of 10 MHz, for example, and calculates an attenuation amount of the VOA 101 based on digital signals input from the ADCs 13a and 13b. Then, a difference between the calculated attenuation amount and the input target value of the attenuation amount is calculated, and a control value of the VOA 101 is calculated so that the difference becomes zero, and this control value is calculated based on the pulse width modulation method and the pulse position. Output as a digital pulse control signal using a modulation method or the like.

  The drive circuit 15 includes a low-pass filter having a band equal to or higher than that of the VOA 101, receives the digital pulse control signal output from the digital processing unit 14, smooths and amplifies it, and drives the VOA 101. An analog drive voltage signal is generated and output. As a result, the VOA 101 is driven so that the attenuation amount becomes a desired target value. By performing such feedback control, the attenuation amount of the VOA 101 is controlled to a desired value.

  FIG. 2 is a circuit diagram showing an example of the configuration of the drive circuit 15 shown in FIG. As shown in FIG. 2, the drive circuit 15 is composed of resistors R1 to R3, capacitors C1 and C2, and an operational amplifier OA, and has a secondary multiple feedback low-pass filter having an amplification function as a whole. It has become. Reference sign Vref represents a reference voltage.

  The drive circuit 15 receives the digital pulse control signal S1 from the input terminal T1, smoothes and amplifies it, generates an analog drive voltage signal for driving the VOA 101, and outputs it from the output terminal T2. Since the digital pulse control signal output from the digital processing unit 14 is as small as 3.3 V or less, for example, and the current value is small, the drive circuit 15 amplifies the digital pulse control signal to a voltage necessary for controlling the VOA 101.

  Here, an example of a digital pulse control signal input to the drive circuit 15 and an analog drive voltage signal output from the drive circuit 15 is shown. The band of the drive circuit 15 is 6 kHz. The digital pulse control signal uses a pulse width modulation method. FIG. 3 shows a digital pulse control signal input to the drive circuit 15 and an analog drive voltage signal output from the drive circuit 15 when the digital code that is an instruction value for generating the digital pulse control signal is “0000”. FIG. The drive circuit 15 is set so that the amplitude of the analog drive voltage signal is 15 V when the digital code is “0000”. Further, the upper part of FIG. 3 shows a digital pulse control signal, and the lower part shows an analog drive voltage signal. In addition, the horizontal axis of FIG. 3 indicates time, and the vertical axis indicates voltage. The horizontal axis scale is 0.5 μs / div, and the vertical axis scale is 20 mV / div. As shown in FIG. 3, when the digital code is “0000”, the period of the digital pulse control signal is about 1.7 μs, but the analog drive voltage signal is smoothed with a ripple. The amplitude of the ripple is 47.2 mV, which is about 0.3% of the maximum amplitude and is extremely small. Furthermore, the analog drive voltage signal is smoothed by the low-pass filter characteristic of the VOA 101 itself, and the ripple amplitude is further reduced.

  4 and 5 show the digital pulse control signal input to the drive circuit 15 and the analog output from the drive circuit 15 when the digital codes for generating the digital pulse control signal are “0800” and “0FFF”, respectively. It is a figure which shows a drive voltage signal. The drive circuit 15 is set so that the amplitude of the analog drive voltage signal is 7.5V and 0V, respectively, when the digital code is “0800” and “0FFF”. As shown in FIGS. 3 and 4, when the digital code is “0800” and “0FFF”, the period of the digital control signal is about 850 ns and about 573 ns, respectively, but the digital code becomes large and the digital pulse control signal The shorter the period is, the smoother the analog drive voltage signal is.

  Next, the response characteristic of the drive circuit 15 when the digital code for generating the digital pulse control signal is changed will be described. 6 and 7 are diagrams showing characteristics of the analog drive voltage signal output from the drive circuit 15 when the digital code for generating the digital pulse control signal input to the drive circuit 15 is instantaneously changed. In FIG. 6, the digital code is changed from “0FFF” to “0000”, and in FIG. 7, the digital code is changed from “0000” to “0FFF”. Waveforms WF1 and WF3 indicate the waveform of the digital pulse control signal, and waveforms WF2 and WF4 indicate the waveform of the analog drive voltage signal. The horizontal scale is 50 μs / div in both FIGS. 6 and 7, and the vertical scale is 2 V / div for the waveforms WF1 and WF3 and 5 V / div for the waveforms WF2 and WF4.

  As shown in FIGS. 6 and 7, when the digital code is instantaneously changed from “0000” to “0FFF” or “0FFF” to “0000”, the analog drive voltage signal changes from 0V to 15V. On such a scale of 0-15V, no ripple was seen in the analog drive voltage signal, and it was confirmed that there was no problem. Further, the time constant is about 30 μs, which is sufficiently smaller than 3 ms, which is the time constant of the VOA 101, so that the VOA 101 can be driven without generating distortion. The maximum value of the repetition period of the digital pulse control signal is 1.7 μs when the digital code is “0000”. If the repetition period is 1/100 or less of the time constant of the VOA 101 as described above, The VOA 101 is preferable because it becomes dense in time so that ripples can hardly be observed on the scale of the time constant.

  As described above, since the time constant of the VOA 101 is sufficiently larger than the time constant of the drive circuit 15, the ripple of the analog drive voltage signal output from the drive circuit 15 is also smoothed in the VOA 101. For example, the band of the VOA 101 is about 53 Hz, but the ripple in the digital code “0000” shown in FIG. 3 is smoothed to an amplitude of 0.1 mV or less.

  As described above, in the control device 10 according to the first embodiment, the drive circuit 15 includes an active filter using an inexpensive operational amplifier, and smoothes and amplifies the digital pulse control signal to drive the VOA 101. Since the analog drive voltage signal to be generated is generated and output, the DAC can be omitted, so that the optical device control apparatus can be reduced in cost, power consumption, and size.

  Here, the relationship between the band of the drive circuit and the ripple will be described more specifically. FIG. 8 is a diagram illustrating the relationship between the bandwidth of the drive circuit and the ratio of the ripple to the maximum amplitude of the analog drive voltage signal in the optical device to be controlled. That is, the ripple in FIG. 8 is a ripple after being smoothed by the low-pass filter characteristic of an optical device such as a VOA. Further, the case where the driving circuit is a first to third order low-pass filter is shown. The band of the drive circuit is normalized with the band of the optical device. The repetition frequency of the digital pulse control signal is set to 1000 times the bandwidth of the optical device.

  Here, in order to stably drive the optical device, the ripple ratio is preferably 0.01% or less, and particularly preferably 0.001% or less. As shown in FIG. 8, if the band of the drive circuit is 100 times or less than the band of the optical device to be controlled, it is preferable because the ripple can be 0.01% or less regardless of the order of the filter. In addition, it is particularly preferable that the band of the drive circuit is 100 times or less of the band of the optical device and the order of the filter is second or higher, because the ripple can be reduced to 0.001% or less.

(Embodiment 2)
Next, a second embodiment of the present invention will be described. The optical device control apparatus according to the second embodiment controls a plurality of VOAs. For example, in a wavelength division multiplexing (WDM) optical transmission system, after dividing a WDM signal into optical signals of respective wavelengths, This is used for the purpose of attenuating the light intensity at each VOA for each signal.

  FIG. 9 is a block diagram of an optical device control apparatus according to the second embodiment. As shown in FIG. 9, the control device 20 (hereinafter referred to as the control device 20) of this optical device has a plurality of VOAs 201 to 101 inserted into each of a plurality of optical fibers F1 to Fn, where n is an integer of 2 or more. 20n is controlled. These VOAs 201 to 20n are the same as the VOA 101 shown in FIG. It is assumed that optical signals having different wavelengths are transmitted to the optical fibers F1 to Fn.

  The control device 20 includes optical couplers 211a to 21na, 211b to 21nb, PD monitors 221a to 22na, 221b to 22nb, ADCs 231a to 23na, 231b to 23nb, a digital processing unit 24, and drive circuits 251 to 25n. . Each component is the same as the corresponding component of the control device 10 shown in FIG.

  The operation of the control device 20 to control each of the VOAs 201 to 20n is the same as that of the control device 10 described above. For example, to describe the VOA 201, the optical coupler 211a branches a part of the optical signal input to the VOA 201 at a predetermined branching ratio. The PD monitor 221a receives a part of the optical signal branched by the optical coupler 211a, converts it into an electrical signal, amplifies it, and outputs an electrical signal corresponding to the detected value of the optical signal input to the VOA 201. The ADC 231 a converts the electrical signal output from the PD monitor 221 a into a digital signal and outputs the digital signal to the digital processing unit 24.

  On the other hand, the optical coupler 211b branches a part of the attenuated optical signal output from the VOA 201 at a predetermined branching ratio. The PD monitor 211b receives a part of the optical signal branched by the optical coupler 211b, converts it into an electrical signal, amplifies it, and outputs an electrical signal corresponding to the detected value of the optical signal output from the VOA 201. The ADC 231 b converts the electrical signal output from the PD monitor 211 b into a digital signal and outputs the digital signal to the digital processing unit 24.

  The digital processing unit 24 is configured by an FPGA as an example, operates with a reference clock frequency of 10 MHz, for example, calculates the attenuation amount of the VOA 201 based on the digital signal input from the ADCs 231a and 231b, The difference between the input attenuation value and the target value is calculated, the control value of the VOA 201 is calculated so that the difference becomes zero, and this control value is converted into a digital pulse using a pulse width modulation method or a pulse position modulation method. Output as a control signal.

  The drive circuit 251 receives the digital pulse control signal output from the digital processing unit 24, smooths and amplifies it, and generates and outputs an analog drive voltage signal for driving the VOA 201. As a result, the VOA 201 is driven so that the attenuation amount becomes a desired target value. By performing such feedback control, the attenuation amount of the VOA 201 is controlled to a desired value.

  Here, the digital processing unit 24 includes a large number of input / output terminals, calculates the attenuation amount of each VOA 201 to 20n based on each digital signal input from the ADCs 231a to 23na and 231b to 23nb, and Compared with the target value of attenuation, a digital pulse control signal indicating a control value is output to each drive circuit 251. As a result, the control device 20 can individually control each of the plurality of VOAs 201 to 20n.

  Thus, when controlling a plurality of VOAs, the same number of DACs as the VOAs are conventionally required. However, the control device 20 can omit the DACs similarly to the control device 10 according to the first embodiment. Therefore, the optical device control apparatus can be significantly reduced in cost, power saving, and downsizing as compared with the prior art.

(Embodiment 3)
FIG. 10 is a block diagram of a main part of the control device for an optical device according to the third embodiment of the present invention. In the control device 30 according to the third embodiment, a sub-digital processing unit 34 is further connected between the digital processing unit 24 and the drive circuits 251 to 25n, but the other points are the same as those of the control device 20. It has a configuration.

  The sub-digital processing unit 34 is composed of, for example, an FPGA, has a number of output terminals, and accepts input of digital pulse control signals to the drive circuits 251 to 25n output from the digital processing unit 24 as parallel or serial signals. The drive circuits 251 to 25n are distributed.

  By including the sub-digital processing unit 34, the control device 30 can individually control more VOAs even when there are few output terminals of the digital processing unit 24, for example. Further, for example, when the digital processing unit 24 performs not only control of the VOA but also other signal processing such as an alarm signal emitted from the VOA, the digital processing unit 24 includes a large number of output terminals, and more sufficiently. Therefore, an expensive one having a sufficient processing capacity is required. However, since the control device 30 includes the sub-digital processing unit 34, the signal processing load of the digital processing unit 24 can be distributed to the sub-digital processing unit 34 and the number of output terminals can be reduced. Can be realized. The sub-digital processing unit 34 only needs to distribute the digital pulse control signal, and may be simpler and less expensive than the digital processing unit 24.

(Embodiment 4)
FIG. 11 is a block diagram of an optical device control apparatus according to Embodiment 4 of the present invention. As shown in FIG. 11, the optical device control device 40 (hereinafter referred to as the control device 40) controls a light source module 401 that is an optical device. The light source module 401 includes a laser diode LD that outputs laser light having a predetermined wavelength. A voltage Vcc is applied to the laser diode LD, and the intensity of the laser beam is changed by changing the drive current. Further, the light source module 401 responds to a change in the driving current of the laser diode LD with a time constant in which the intensity of the output laser light is sufficiently larger than the repetition cycle of the digital pulse control signal.

  The control device 40 includes an optical coupler 41, a PD monitor 42, an ADC 43, a digital processing unit 44, a drive circuit 45, and a field effect transistor (FET) 46 that is a current amplifier. The optical coupler 41 is disposed on the light output side of the light source module 401 and branches a part of the laser light output from the light source module 401 at a predetermined branching ratio. The PD monitor 42 receives a part of the optical signal branched by the optical coupler 41, converts it into an electrical signal, amplifies it, and outputs an electrical signal corresponding to the detected value of the intensity of the laser beam output from the light source module 401. The ADC 43 converts the electrical signal output from the PD monitor 42 into a digital signal and outputs the digital signal to the digital processing unit 44.

  The digital processing unit 44 calculates a difference between the detected intensity of the laser light and the target value of the light intensity based on the digital signal input from the ADC 43, and obtains a control value of the light source module 401 such that the difference becomes zero. The calculated value is output as a digital pulse control signal.

  The drive circuit 45 includes a low-pass filter having a band equal to or higher than that of the light source module 401. The drive circuit 45 receives the digital pulse control signal output from the digital processing unit 44, smooths and amplifies the digital pulse control signal, and supplies the light source module. An analog drive voltage signal for driving 401 is generated and output. Further, the FET 46 amplifies the analog drive voltage signal to a predetermined current value, and passes it to the laser diode LD. As a result, the light source module 401 is driven so that the intensity of the laser beam to be output becomes a desired target value. By performing such feedback control, the output laser light intensity of the light source module 401 is controlled to a desired value.

  Similarly to the control devices 10 to 30, the control device 40 can omit the DAC, and thus can be an optical device control device that can be easily reduced in cost, reduced in power consumption, and reduced in size.

(Embodiment 5)
FIG. 12 is a block diagram of an optical device control apparatus according to Embodiment 5 of the present invention. As shown in FIG. 12, this optical device control device 50 (hereinafter referred to as control device 50) controls an optical amplification module 501 that is an optical device. The optical amplification module 501 includes an amplification optical fiber DF to which ions of erbium, which is a rare earth metal element, is added. This amplification optical fiber DF has an action of amplifying and outputting, for example, input light of a wavelength of 1.55 μm band by supplying excitation light and bringing erbium ions into an excited state. Note that the amplification gain of the amplification optical fiber DF varies depending on the ambient temperature. Therefore, the optical amplification module 501 includes a heater H for adjusting the ambient temperature. By controlling the temperature of the heater H to a constant value, the ambient temperature of the amplification optical fiber DF is made constant and the amplification gain is made constant. Can be controlled. The optical amplification module 501 responds to a change in the driving current of the heater H with a time constant whose temperature is sufficiently larger than the repetition cycle of the digital pulse control signal.

  The control device 50 includes a temperature detector 52a, a temperature monitor 52, an ADC 53, a digital processing unit 54, a drive circuit 55, and an FET 56. The temperature detector 52 a is a thermistor, for example, and is disposed in the vicinity of the heater H. The temperature monitor 52 outputs an electrical signal corresponding to the detected temperature value detected by the temperature detector 52a. The ADC 53 converts the electrical signal output from the temperature monitor 52 into a digital signal and outputs the digital signal to the digital processing unit 54.

  The digital processing unit 54 calculates the difference between the detected temperature of the heater H and the target temperature value based on the digital signal input from the ADC 53, and calculates the control value of the heater H such that the difference becomes zero. The control value is output as a digital pulse control signal.

  The drive circuit 55 includes a low-pass transmission filter having a band equal to or higher than that of the optical amplification module 501, receives a digital pulse control signal output from the digital processing unit 54, smooths and amplifies the digital pulse control signal, and heats the heater An analog drive voltage signal for driving H is generated and output. Further, the FET 56 amplifies the analog drive voltage signal to a predetermined current value and passes it to the heater H. As a result, the heater H is driven so that the temperature becomes a desired target value. By performing such feedback control, the amplification gain of the optical amplification module 501 is controlled to a desired value.

  Similarly to the control devices 10 to 40, the control device 50 can omit the DAC, and thus can be an optical device control device that can be easily reduced in cost, saved in power, and downsized.

  The first to third embodiments described above are cases where the Maha-Zehnder type VOA is controlled. However, for example, when controlling the MEMS type VOA in which the internal actuator is voltage-driven to change the amount of attenuation. However, the present invention is applicable.

  In the first to third embodiments, the optical intensities of both optical signals input to and output from the VOA are monitored. However, for example, only the output optical intensity may be monitored and the VOA may be controlled at a constant output intensity. . In addition, a correspondence table of voltage values and VOA attenuation amounts is stored in a memory inside the digital processing unit, and a digital pulse control signal representing a predetermined control value is output based on the control target value. The attenuation amount of the VOA may be controlled without monitoring the intensity.

  In the first to fifth embodiments, an active filter using an operational amplifier is used for the drive circuit. However, the drive circuit may be configured by combining an LC filter as a low-pass filter and an FET.

It is a block diagram of the control apparatus of the optical device which concerns on Embodiment 1 of this invention. FIG. 2 is a circuit diagram illustrating an example of a configuration of a drive circuit illustrated in FIG. 1. It is a figure which shows the digital pulse control signal input into a drive circuit in case the digital code which generates a digital pulse control signal is "0000", and the analog drive voltage signal output from a drive circuit. It is a figure which shows the digital pulse control signal input into a drive circuit in case the digital code which generates a digital pulse control signal is "0800", and the analog drive voltage signal output from a drive circuit. It is a figure which shows the digital pulse control signal input into a drive circuit when the digital code which generates a digital pulse control signal is "0FFF", and the analog drive voltage signal output from a drive circuit. It is a figure which shows the characteristic of the analog drive voltage signal output from a drive circuit at the time of changing the digital code which generates the digital pulse control signal input into a drive circuit instantaneously. It is a figure which shows the characteristic of the analog drive voltage signal output from a drive circuit at the time of changing the digital code which generates the digital pulse control signal input into a drive circuit instantaneously. It is a figure which shows the relationship between the zone | band of a drive circuit, and the ratio of the ripple with respect to the maximum amplitude of the analog drive voltage signal in the optical device which is a control object. It is a block diagram of the control apparatus of the optical device which concerns on Embodiment 2 of this invention. It is a block diagram of the principal part of the control apparatus of the optical device which concerns on Embodiment 3 of this invention. It is a block diagram of the control apparatus of the optical device which concerns on Embodiment 4 of this invention. It is a block diagram of the control apparatus of the optical device which concerns on Embodiment 5 of this invention.

Explanation of symbols

10 to 40 Control devices 11a, 11b, 211a to 21na, 211b to 21nb, 41 Optical couplers 12a, 12b, 221a to 22na, 221b to 22nb, 42 PD monitors 13a, 13b, 231a to 23na, 231b to 23nb, 43, 53 ADC
14, 24, 44, 54 Digital processing unit 15, 251-2n, 45, 55 Drive circuit 34 Sub-digital processing unit 52 Temperature monitor 52a Temperature detector 101, 201-20n VOA
401 Light source module 501 Optical amplification module C1, C2 Capacitor DF Amplification optical fiber F, F1-Fn Optical fiber H Heater LD Laser diode OA Operational amplifier R1-R3 Resistance S1 Digital pulse control signal S2 Analog drive voltage signal T1 Input terminal T2 Output terminal Vcc Voltage Vref Reference voltage WF1-WF4 Waveform

Claims (2)

An optical device;
Detecting means for detecting a characteristic of said optical device,
AD conversion means for AD converting the detected value of the detected characteristic;
Digital processing means for receiving an input of the converted detection value, and generating and outputting a digital pulse control signal representing a control value for the optical device to be controlled based on the detection value and a control target value;
A low-pass filter that is directly connected to the optical device, has a band equal to or higher than the band of the optical device, and is an active filter including an operational amplifier, and the low-pass filter is an input of the digital pulse control signal Driving means for smoothing and amplifying the digital pulse control signal to generate an analog drive signal, and outputting the analog drive signal as a drive signal for driving the optical device;
The provided, repetition period of the digital pulse control signal, the optical device equipment, characterized in that when it is less than 1/100 of constants of the optical device. The band drive means, optical devices equipment according to claim 1, characterized in that not more than 100 times the bandwidth of the optical device.

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