JP6775024B2 - Optical wavelength measuring device - Google Patents

Description

The present invention relates to an optical wavelength measuring device.

An optical wavelength change type sensor having a fiber Bragg grating (FBG) element that outputs a wavelength corresponding to a physical quantity, and an optical wavelength measuring device using another sensor are known.
As a conventional example of an optical wavelength measuring device, there is an optical sensor measuring device that acquires reflection spectra of a plurality of FBG sensors using a variable wavelength light source and measures a value of a peak wavelength in the spectrum (Patent Document 1). In the conventional example of Patent Document 1, the tunable light source sweeps the wavelength of the output light in synchronization with the control clock. When the variable wavelength light source sweeps light of wavelengths λs to λe and reaches the reflected wavelength of each FBG sensor, the reflected light passes through a circulator and is converted into a voltage by a photoelectric conversion circuit. By measuring which wavelength the tunable light source outputs when the peak of the voltage waveform is obtained, the wavelength of the peak can be obtained.

As another conventional example, a light source having an FBG, an acoustic-optical wavelength variable filter input by a reference light output from the light source and a light to be measured output from a sensor, and an output light output from the acoustic-optical wavelength filter are used. There is an optical spectrum analyzer equipped with a light receiving receiver that corrects the wavelength of the selected light obtained from the light to be measured by a computing device based on the wavelength of the selected light and the excitation frequency when the reference light is incident (patented). Document 2).

As another conventional example, from a waveguide type acoustic optical wavelength variable filter into which the light to be measured is input, a heating adjustment heater for heating and retaining the waveguide type acoustic optical wavelength variable filter, and a waveguide type acoustic optical wavelength variable filter. There is an optical spectrum analyzer that includes a receiver that receives the output light and calculates the optical spectrum of the light to be measured based on the output signal from the receiver (Patent Document 3).

Japanese Unexamined Patent Publication No. 2010-151601 International Publication No. 2007/083609 International Publication No. 2008/152879

In the conventional example of Patent Document 1, since a plurality of threshold values are set, the structure of the apparatus becomes complicated and expensive. Further, the setting itself becomes complicated and it becomes inconvenient to use.
In the conventional example of Patent Document 2, it is premised that the reference light itself does not have temperature characteristics. Since the reference light is an FBG, it is necessary to make the temperature control function for keeping the FBG at a constant temperature and the FBG itself athermal, but there is no disclosure of means for achieving this.
In the conventional example of Patent Document 3, since a Peltier element or a resistance heater is used as a heater for heating and retaining the waveguide type acoustic-optical wavelength tunable filter, it is complicated and complicated due to poor followability to ambient temperature changes. Expensive means are required.

An object of the present invention is to provide an optical wavelength measuring device having a simple structure, having high stability against temperature changes, and capable of performing a wide range of measurements with high accuracy.

The optical wavelength measuring device of the present invention includes an acoustic-optical wavelength variable filter that selectively extracts a predetermined wavelength from input light, a high-frequency voltage generation circuit that excites the acoustic-optical wavelength variable filter by applying a high-frequency signal, and an arbitrary reference. A reference wavelength generator that outputs wavelength light, an optical wavelength change type sensor that is installed on the object to be measured and outputs light having a wavelength corresponding to a physical quantity, and output light output from the acoustic-optical wavelength variable filter are used as the reference wavelength. An input unit to be input to each of the generator and the optical wavelength change type sensor, and an output light that receives the output light output from the reference wavelength generator and is output by the optical wavelength change type sensor. A light receiver for measurement light that receives light through the input unit, a reference light receiver that receives output light output from the acoustic-optical wavelength variable filter as reference light via a separation unit, and a light receiver for measurement light. An arithmetic circuit that calculates the wavelength of the optical wavelength change type sensor based on signals output from the device and the reference light receiver, a filter temperature detection unit that detects the temperature of the acoustic-optical wavelength variable filter, and the above. It is characterized by including a control unit that controls a frequency signal output by the high-frequency voltage generation circuit to the acoustic-optical wavelength variable filter based on a temperature signal output from the filter temperature detection unit.

In the present invention, when the high-frequency voltage generation circuit is driven, a predetermined wavelength is selectively extracted from the input light by an acoustic-optical wavelength tunable filter called AOTF. The output light selectively extracted is input to the reference wavelength generator and the optical wavelength change type sensor by the input unit. In the optical wavelength change type sensor, light having a wavelength corresponding to a physical quantity is output, and this output light is sent to a receiver for measurement light by an input unit. The output light output from the reference wavelength generator is sent to the light receiver for measurement light. The signal output from the light receiver for measurement is sent to an arithmetic circuit, and this arithmetic circuit calculates the wavelength according to the physical quantity of the optical wavelength type sensor.
Moreover, since it is equipped with a filter temperature detection unit and a control unit, the temperature of the acoustic-optical wavelength variable filter is detected by the filter temperature detection unit, and the control unit has a high frequency based on the temperature signal from the filter temperature detection unit. The voltage generation circuit controls the frequency signal output to the acoustic-optical wavelength variable filter. As a result, the wavelength range of the output light sent from the acoustic-optical wavelength variable filter to the reference wavelength generator and the optical wavelength change type sensor becomes the wavelength range of the output light whose temperature has been corrected. Therefore, it is possible to output output light having a specific wavelength from the acoustic-optical wavelength tunable filter without being affected by the temperature change, and it is possible to provide an optical wavelength measuring device having high stability against the temperature change.

In the present invention, the temperature detection unit for the generator that detects the temperature of the reference wavelength generator is provided, and the arithmetic circuit is output from the reference wavelength generator based on the temperature signal output from the temperature detection unit for the generator. A configuration having a wavelength calculation unit that calculates the wavelength of the output light is preferable.
In this configuration, since the temperature detector for the generator is provided in the reference wavelength generator, even if the reference wavelength generator affected by the temperature change is used, the temperature signal of the detected reference wavelength generator is used to generate the reference wavelength generator. The wavelength of the output light output from is calculated by the wavelength calculation unit to improve the measurement accuracy.

In the present invention, the optical amplifier arranged on the optical input side or the optical output side of the acoustic-optical wavelength variable filter, and the output light output from one of the acoustic-optical wavelength variable filter and the optical amplifier are variable in the acoustic-optical wavelength. A configuration including a filter and a feedback unit that feeds back to the other side of the optical amplifier is preferable.
With this configuration, it is possible to easily increase the intensity of light input to the reference wavelength generator or the optical wavelength change type sensor and the wavelength range of sweeping.

In the present invention, it is preferable that the acoustic-optical wavelength tunable filter and the filter temperature detection unit are arranged in the same casing.
In this configuration, since the acoustic-optical tunable filter and the filter temperature detector arranged in the same casing are in an approximate temperature environment, the temperature of the acoustic-optical tunable filter is correctly detected by the filter temperature detector. Therefore, the measurement accuracy can be improved.

In the present invention, it is preferable that the acoustic-optical wavelength tunable filter and the reference wavelength generator are arranged in the same casing.
In this configuration, since the acoustic-optical tunable filter in the same casing and the reference wavelength generator are in an approximate temperature environment, the temperature detector for the filter can also serve as the temperature detector for the generator, and the number of parts can be increased. It can be reduced.

In the present invention, it is preferable that the light receiver for measurement light is arranged in the same casing as the acoustic-optical wavelength tunable filter and the reference wavelength generator.
In this configuration, since the receiver for measurement light is arranged in the same casing together with the acoustic-optical wavelength tunable filter and the reference wavelength generator, an optical cable for connecting these members becomes unnecessary, and cost can be reduced.

The optical wavelength measuring device of the present invention includes an acoustic-optical wavelength variable filter that selectively extracts a predetermined wavelength from input light , a high-frequency voltage generation circuit that excites the acoustic-optical wavelength variable filter by applying a high-frequency signal, and an arbitrary reference. A reference wavelength generator that outputs wavelength light, an optical wavelength change type sensor that is installed on an object to be measured and outputs light having a wavelength corresponding to a physical quantity, and an output light output from the acoustic-optical wavelength variable filter are used as the reference wavelength. An input unit to be input to the generator and the optical wavelength change type sensor, and an output light that receives the output light output from the reference wavelength generator and is output by the optical wavelength change type sensor. A light receiver for measurement light that receives light via the input unit, an arithmetic circuit that calculates the wavelength of the optical wavelength change type sensor based on a signal output from the light receiver for measurement light, and an acoustic-optical wavelength variable filter. A filter temperature detection unit that detects the temperature of the filter, and a control unit that controls a frequency signal output by the high-frequency voltage generation circuit to the acoustic-optical wavelength variable filter based on the temperature signal output from the filter temperature detection unit. The input unit includes a first input unit that inputs the output light output from the acoustic-optical wavelength variable filter to the reference wavelength generator, and the input unit that outputs the output light output from the acoustic-optical wavelength variable filter. The measurement light receiver has a second input unit for inputting to an optical wavelength change type sensor, and the measurement light receiver includes a first receiver that receives output light output from the reference wavelength generator and the optical wavelength change type. A reference light receiver that has a second receiver that receives the output light output by the sensor via the second input unit, and further receives the output light output from the acoustic-optical wavelength variable filter. The output value of the signal output from the reference light receiver and the separation unit that separates the output light output from the acoustic-optical wavelength variable filter into the second input unit and the reference light receiver. characterized in that and a divider for dividing an output value of the signal output from at least one of said first photodetector and said second photodetector.
In this configuration, the output light output from the acoustic-optical tunable filter is sent to the reference wavelength generator by the first input unit, and the reference wavelength light is sent from the reference wavelength generator to the first receiver. The output light output from the acoustic-optical tunable filter is separated into a second input unit and a reference light receiver by a separation unit. The output light sent to the second input unit is sent to the optical wavelength change type sensor, and the reflected light reflected by the optical wavelength change type sensor is sent to the second receiver as measurement light via the second input unit. The output light sent from the separation unit is sent to the reference light receiver as reference light. Output signals are sent from the first receiver, the second receiver, and the reference light receiver to the divider, and the divider determines the output value of the reference light, which is the output value of the reference wavelength light and the output value of the measurement light. Division is carried out.
The reference wavelength generator and the optical wavelength change type depending on the type and individual difference of the light source that inputs the input light to the acoustic-optical wavelength variable filter, the type and individual difference of the acoustic-optical wavelength variable filter itself, the temperature change, the time change, etc. Although the optical spectrum profile input to the sensor fluctuates, the influence of the fluctuation of the optical spectrum profile can be easily reduced by the above configuration at low cost. Moreover, it is not necessary to adopt a configuration in which a plurality of threshold values are set, and the structure of the optical wavelength measuring device can be simplified.
Further, since the light receiver for measurement light is divided into a first light receiver and a second light receiver, the reference light and the output light output from the light wavelength change type sensor should be in the same light wavelength band. With a simple structure, a wide range of measurements can be performed with high accuracy.

The schematic diagram which shows the light wavelength measuring apparatus which concerns on 1st Embodiment of this invention. The graph which shows the relationship between the time and the light receiving intensity output from a light receiving part. A graph showing the relationship between the wavelength and voltage of the signal output from the reference light receiver. The graph which shows the relationship between the wavelength and the voltage of the signal output from the receiver for measurement light. A graph showing the relationship between the wavelength and voltage of the signal output from the divider. A graph showing the relationship between the sweep frequency and temperature input from the high-frequency voltage generation circuit to the acoustic-optical tunable filter. A graph showing the relationship between the wavelength of the output light output from the reference wavelength generator and the transmittance. A graph showing the relationship between the temperature and wavelength of the output light output from the reference wavelength generator. The schematic diagram which shows the light wavelength measuring apparatus which concerns on 2nd Embodiment of this invention. The schematic which shows the light wavelength measuring apparatus which concerns on 3rd Embodiment of this invention. The schematic diagram which shows the light wavelength measuring apparatus which concerns on 4th Embodiment of this invention. The schematic diagram which shows the light wavelength measuring apparatus which concerns on 5th Embodiment of this invention. The schematic which shows the light wavelength measuring apparatus which concerns on 6th Embodiment of this invention. The schematic which shows the light wavelength measuring apparatus which concerns on 7th Embodiment of this invention. The schematic diagram which shows the light wavelength measuring apparatus which concerns on 8th Embodiment of this invention. The schematic diagram which shows the light wavelength measuring apparatus which concerns on 9th Embodiment of this invention. The schematic which shows the light wavelength measuring apparatus which concerns on the tenth embodiment of this invention. The schematic diagram which shows the light wavelength measuring apparatus which concerns on 11th Embodiment of this invention.

Embodiments of the present invention will be described with reference to the drawings. Here, in the description of each embodiment, the same components are designated by the same reference numerals and the description thereof will be omitted.
[First Embodiment]
The light wavelength measuring device 1 according to the first embodiment will be described with reference to FIG.
FIG. 1 shows a schematic configuration of the light wavelength measuring device 1.
In FIG. 1, the optical wavelength measuring device 1 includes an optical module 10, an optical wavelength change type sensor 20 connected to the optical module 10, a light receiving unit 3A, a control unit 40, a high frequency voltage generating circuit 50, and a light receiving unit 3A. It includes an arithmetic circuit 60 to be connected, an output unit 70 connected to the arithmetic circuit 60, and a light source 80.
The light receiving unit 3A includes a light receiving device 30 for measurement light and a light receiving device 33 for reference light.
The light source 80 is composed of a broadband light source.

The optical module 10 includes an acoustic-optical wavelength tunable filter 12, a reference wavelength generator 13, an input unit 140, and a separation unit 151, which are provided in the casing 11, respectively. The input unit 140 is composed of a beam splitter and a circulator.
Adjacent members of the acoustic-optical wavelength tunable filter 12, the reference wavelength generator 13, the input unit 140, and the separation unit 151 are connected by an optical fiber. Further, the separation unit 151 and the reference light receiver 33, and the input unit 140 and the measurement light receiver 30 are each connected by an optical fiber or are connected via a space.
The acoustic optical tunable filter 12 is an element that selectively extracts a predetermined wavelength from input light, and is called an AOTF (Acoustro Optical Tunable Filter).
The acoustic-optical wavelength variable filter 12 is a waveguide type filter having an IDT 120 that receives input light from a light source 80 and a high-frequency signal from a high-frequency voltage generation circuit 50. The IDT120 is an Inter Digital Transducer (comb electrode). The reference wavelength generator 13 is composed of elements such as an etalon, a gas cell (hydrogen cyanide (HCN)), a fiber Bragg grating (FBG), and a dielectric multilayer filter.
The reference wavelength generator 13 outputs the output light output by the acoustic-optical wavelength variable filter 12 to the optical wavelength change type sensor 20, and the output light from the optical wavelength change type sensor 20 is used as an arbitrary reference wavelength light in the input unit 140. Send to.

The input unit 140 measures the output light (measurement light) corresponding to the physical quantity of the light wavelength change type sensor 20 from the light wavelength change type sensor 20 and the reference wavelength light output from the reference wavelength generator 13 for the measurement light receiver 30. Is to be input to.
The separation unit 151 is arranged between the acoustic-optical wavelength variable filter 12 and the input unit 140, and the output light output from the acoustic-optical wavelength variable filter 12 is directed to the input unit 140 and the reference light. It is separated from the reference light directed to the receiver 33.

The optical wavelength change type sensor 20 is composed of a single sensor or a plurality of sensors on an optical fiber, and is installed on an object to be measured (not shown). Here, the sensor includes a derivative multilayer film filter type, an FBG type, and a Fabry-Perot interference type.
The optical wavelength change type sensor 20 inputs the output light of the acoustic-optical wavelength variable filter 12 via the input unit 140, and emits the reflected light toward the input unit 140. Here, the reflected light output by the light wavelength change type sensor 20 corresponds to a change in the physical quantity of the object to be measured in which the light wavelength change type sensor 20 is installed.
The arithmetic circuit 60 receives the signals output from the measurement light receiver 30 and the reference light receiver 33, respectively, and the wavelength of the optical wavelength change type sensor 20 by receiving the output signals from the divider 600. It is configured to include a wavelength calculation unit 63 for calculating.

A method of calculating the physical quantity detected by the optical wavelength change type sensor 20 by using the wavelength calculation unit 63 will be described with reference to FIG. FIG. 2 shows the relationship between the time and the light receiving intensity output from the light receiving unit 3A.
In FIG. 2, the light receiving intensity of the reference wavelength light output from the measurement light receiver 30 peaks at wavelengths λ _r1 , λ _r2 , λ _r3 , λ _r4 , and λ _r5 . is a time _{t r1} at the time of λ _r1, is a time _{t r2} at the time of λ _r2, the time is _{t r3} at the time of λ _r3, time of time of λ _r4 is _{t r4, λ r5} The time at is _tr5 .
If two light wavelength change type sensors 20 are used, the light receiving intensity of the measurement light output from the measurement light receiver 30 peaks at the wavelengths λ _f1 and λ _f2 . The time at λ _f1 is t _f1 , and the time at λ _f2 is t _f2 .
For example, the wavelength calculation unit 63 obtains the wavelength λ _f1 and the wavelength λ _f2 of the optical wavelength change type sensor 20 by the following calculation formula.
λ _f1 = {(λ _r3 −λ _r2 ) / ( _{tr r3-} t _r2 )} · t _f1 + λ _r2
λ _f2 = {(λ _r5- λ _r4 ) / (t _r5- t _r4 )} · t _f2 + λ _r4
The wavelength calculated by the wavelength calculation unit 63 is output to the output unit 70. The wavelength calculation method is obtained from the relative time difference between λ _rn and λ _fn, and is not limited to the method based on the above-mentioned calculation formula.
The output unit 70 may be a display unit that displays the value of the wavelength calculated by the wavelength calculation unit 63, or may be a memory such as a LAN, a hard disk (HD), or an SD card.

In FIG. 1, each of the measurement light receiver 30 and the reference light receiver 33 has an amplifier and constitutes a photoelectric conversion circuit.
The output light output from the acoustic-optical wavelength tunable filter 12 is branched into two by the separation unit 151. One of the output lights branched into two by the separation unit 151 is sent to the optical wavelength change type sensor 20 via the input unit 140. The output from the optical wavelength change type sensor 20, that is, the reflected light (λ ₁ , λ ₂ , ... λ _n ) is received by the measurement light receiver 30 as measurement light. The measurement light is converted into a signal having a spectral waveform by the measurement light receiver 30. This spectrum is shown in FIG. 3B. It can be seen that the spectral waveform shown in FIG. 3B has a high voltage at a wavelength of around 1545 nm and has a chevron shape.

The other of the output light branched into two by the separation unit 151 is received by the reference light receiver 33 as reference light. The reference light is converted into a signal having a spectral waveform by the reference light receiver 33. This spectrum is shown in FIG. 3A.
In the reference light receiver 33, the spectral shape of the output light output by the acoustic-optical tunable filter 12 and the change with time are shown. In FIGS. 3B and 3C, Th indicates a threshold value. The threshold Th is 0.6V.
The signal of the spectrum waveform shown in FIG. 3B is obtained by multiplying the reflection spectrum of the optical wavelength change type sensor 20 by the spectrum of the acoustic-optical wavelength variable filter 12.

The signals output from the measurement light receiver 30 and the reference light receiver 33 are sent to the divider 600.
The divider 600 divides the output value of the signal output from the measurement light receiver 30 by the output value of the signal output from the reference light receiver 33. As shown in FIG. 3C, it can be seen that the signal of the spectral waveform after division is less affected by the spectrum of the acoustic-optical wavelength tunable filter 12.

In FIG. 1, the high-frequency voltage generation circuit 50 applies a high-frequency signal to the acoustic-optical wavelength variable filter 12 to excite it, and amplifies the high-frequency signal generation element 51 and the high-frequency signal output from the high-frequency signal generation element 51. It has an amplifier 52 to send to the IDT 120.
The high frequency signal generator 51 is composed of a voltage control oscillator (VCO) and a digital IC (Direct Digital Synthesizer) that generates a waveform using a DA converter.
The casing 11 is provided with a filter temperature detection unit 91 that detects the temperature of the acoustic-optical wavelength tunable filter 12.
The filter temperature detection unit 91 is composed of elements such as a thermocouple, a thermistor, and a platinum resistance temperature detector that detect the temperature.
The temperature signal of the acoustic-optical wavelength tunable filter 12 detected by the filter temperature detection unit 91 is sent to the control unit 40, and the high-frequency signal generation element 51 is controlled by the control unit 40.

FIG. 4 shows the relationship between the sweep frequency and the temperature input from the high-frequency voltage generation circuit 50 to the acoustic-optical tunable filter 12.
In FIG. 4, the sweep frequency region input from the high-frequency voltage generation circuit 50 to the acoustic-optical tunable filter 12 is shown by diagonal lines.
The sweep start position is indicated by fa and the sweep end is indicated by fb. If C is a constant
fa−fb = C.
If C is, for example, 10 MHz and fa is, for example, 180 MHz, fb is 170 MHz.

The sweep start position fa is represented by the following equation expressing the temperature t as a variable.
fa = fr + α (t-tr)
Here, α is a frequency temperature coefficient, which is a unique value of the acoustic-optical wavelength tunable filter 12, and is usually 0.1 MHz / ° C.
tr is the reference temperature (for example, 25 ° C.), and fr is the sweep start frequency at the reference temperature.
This equation determines the sweep start frequency.
That is, the control unit 40 that receives the signal of the temperature tr detected by the temperature detection unit 91 for the filter determines the frequency fr of the sweep start based on the above equation and the graph of FIG. 4, and a constant value from this frequency fr. A signal is sent to the high frequency signal generating element 51 so as to sweep in the range of C (for example, 10 MHz).

In FIG. 1, a generator temperature detection unit 92 that detects the temperature of the reference wavelength generator 13 is arranged inside the casing 11.
The temperature signal of the reference wavelength generator 13 detected by the temperature detection unit 92 for the generator is sent to the wavelength calculation unit 63. As will be described later, the wavelength calculation unit 63 corrects the wavelength of the output light output by the reference wavelength generator 13 based on the temperature signal output from the generator temperature detection unit 92.

FIG. 5 shows the relationship between the wavelength of the output light output from the reference wavelength generator 13 and the transmittance.
As shown in FIG. 5, the transmittances of the wavelength λrm-1, the wavelength λrm, and the wavelength λrm + 1 are small at a temperature of 0 ° C. and are small at a temperature of 60 ° C., respectively, mainly when the temperature is 30 ° C. Is big. In this way, the wavelength of the output light output from the reference wavelength generator 13 changes due to the influence of temperature. For example, when a quartz solid etalon is used as the reference wavelength generator 13, the amount of change is about 30 ° C. and 60 ° C. and 0 ° C. and 30 ° C., respectively. It is 5 pm / ° C.

FIG. 6 shows the relationship between the temperature and wavelength of the output light output from the reference wavelength generator 13.
In FIG. 6, as the temperature rises, the wavelengths of wavelength λrm-1, wavelength λrm, and wavelength λrm + 1 become larger, respectively. Here, the wavelength λrm of the reference wavelength generator 13 is expressed by the following equation with the temperature t as a variable.
λrm = λtr + β (t-tr)
Here, β is a wavelength temperature coefficient, which is a unique value of the reference wavelength generator 13. t is the temperature obtained by the temperature detection unit 92 for the generator, tr is the reference temperature, and λtr is the wavelength of the output light output by the reference wavelength generator 13 at the reference temperature tr.

Therefore, in the first embodiment, the following effects can be obtained.
(1) The temperature of the acoustic-optical wavelength variable filter 12 is detected by the filter temperature detection unit 91, and the control unit 40 uses the high-frequency voltage generation circuit 50 to detect the temperature of the acoustic-optical wavelength variable filter 12 based on the temperature signal from the filter temperature detection unit 91. The frequency signal output to 12 is controlled. Therefore, the output light sent from the acoustic-optical wavelength variable filter 12 to the reference wavelength generator 13 and the optical wavelength change type sensor 20 can be temperature-corrected output light, and the optical wavelength measurement with high stability against temperature change can be performed. Equipment can be provided.

(2) Since the temperature detection unit 92 for the generator is provided in the reference wavelength generator 13, the wavelength calculation unit calculates the calculation result of the reference wavelength output from the reference wavelength generator 13 using the detected temperature signal of the reference wavelength generator 13. The measurement accuracy can be improved by correcting with 63.

(3) Since the acoustic-optical wavelength tunable filter 12 and the filter temperature detection unit 91 are arranged inside the same casing 11, these members are in an approximate temperature environment. Therefore, the temperature of the acoustic-optical wavelength tunable filter 12 is accurately detected by the filter temperature detecting unit 91, and the measurement accuracy can be improved.
(4) Since the reference wavelength generator 13 and the generator temperature detection unit 92 are arranged inside the same casing 11, these members are in an approximate temperature environment. Therefore, the temperature of the reference wavelength generator 13 is accurately detected by the temperature detection unit 92 for the generator, and the measurement accuracy can be further improved.

(5) Since the acoustic-optical wavelength tunable filter 12 and the reference wavelength generator 13 are arranged inside the same casing 11, these members are in an approximate temperature environment. Therefore, the filter temperature detection unit 91 can also serve as the generator temperature detection unit 92, and the number of parts can be reduced. When the filter temperature detection unit 91 also serves as the generator temperature detection unit 92, the temperature signal S from the filter temperature detection unit 91 of FIG. 1 is sent to the wavelength calculation unit 63.

(6) A reference light receiver 33 that receives the output light output from the acoustic-optical wavelength variable filter 12, and an input unit 140 and a reference light receiver 33 that receive the output light output from the acoustic-optical wavelength variable filter 12. Since it is provided with a separation unit 151 that separates the light receivers 151 and a divider 600 that divides the output value of the signal output from the light receiver 30 for measurement by the output value of the signal output from the light receiver 33 for reference light. The influence of fluctuations in the optical spectrum profile input to the reference wavelength generator 13 and the optical wavelength change type sensor 20 caused by the type and individual difference of the wavelength variable filter 12, temperature change, time change, etc. can be easily reduced at low cost.

[Second Embodiment]
Next, the second embodiment of the present invention will be described with reference to FIG.
The second embodiment is different from the first embodiment in that the light receiving portion 3A is arranged inside the casing 11, and other configurations are the same as those of the first embodiment.
FIG. 7 shows a schematic configuration of the light wavelength measuring device 2 according to the second embodiment.
In FIG. 7, the optical wavelength measuring device 2 includes a casing 11, an acoustic-optical wavelength variable filter 12 arranged inside the casing 11, a filter temperature detection unit 91, an input unit 140, a separation unit 151, and a reference wavelength generator. 13. It is provided with a temperature detection unit 92 for a generator and a light receiving unit 3A.

The acoustic-optical wavelength tunable filter 12, the separation unit 151, the input unit 140, the reference wavelength generator 13, the measurement light receiver 30, and the reference light receiver 33 are arranged in a straight line with predetermined gaps, respectively. Unlike the first embodiment, the optical fiber is not arranged between them, but is a space. Also in the present embodiment, as in the first embodiment, the acoustic-optical tunable filter 12, the separation unit 151, the input unit 140, the reference wavelength generator 13, the measurement light receiver 30, and the reference light receiver 33 are also used. Each of them may be connected by an optical fiber.

In the second embodiment, the same effects as those in (1) to (6) of the first embodiment can be obtained, and the following effects can be obtained.
(7) The light receiver 30 for measurement light and the light receiver 33 for reference light are arranged inside the same casing 11 as the acoustic-optical wavelength tunable filter 12 and the reference wavelength generator 13. Therefore, by providing a space between these members, an optical cable for connecting them becomes unnecessary, and cost reduction can be achieved.

[Third Embodiment]
Next, the third embodiment of the present invention will be described with reference to FIG.
The third embodiment is different from the first embodiment in that the input unit 140, the light receiver 30 for measurement light, and the divider 600 are each composed of two, and the other configurations are different from those of the first embodiment. It is the same.
FIG. 8 shows a schematic configuration of the light wavelength measuring device 3 according to the third embodiment.
In FIG. 8, the optical wavelength measuring device 3 includes a casing 11, an acoustic-optical wavelength tunable filter 12, a filter temperature detection unit 91, an input unit 140, a separation unit 151, and a reference wavelength generation, which are arranged inside the casing 11, respectively. It includes a device 13, a temperature detection unit 92 for a generator, a light receiving unit 3A, and an arithmetic circuit 60 connected to the light receiving unit 3A.

The light receiving unit 3A includes a light receiving device for measurement light and a light receiving device 33 for reference light, and the light receiving device 30 for measurement light has a first light receiving device 31 and a second light receiving device 32.
The input unit 140 is a first input unit 141 arranged between the acoustic and optical tunable filter 12 and the separation unit 151, and a second input unit arranged between the separation unit 151 and the optical wavelength change type sensor 20. It is equipped with 142.
The first input unit 141 causes the reference wavelength generator 13 to input the output light output from the acoustic-optical tunable filter 12.
The second input unit 142 sends the output light from the acoustic-optical wavelength variable filter 12 via the separation unit 151 to the optical wavelength change type sensor 20, and uses the output light corresponding to the physical quantity of the optical wavelength change type sensor 20 as the measurement light. (Ii) The output is to the receiver 32.

The reference wavelength generator 13 inputs the output light output by the acoustic-optical tunable filter 12 via the first input unit 141, and outputs an arbitrary reference wavelength light to the first receiver 31.
The separation unit 151 separates the output light output from the acoustic-optical tunable filter 12 into an output light directed to the second input unit 142 and a reference light directed to the reference light receiver 33. Here, the reference light from the separation unit 151 toward the reference light receiver 33 and the output light from the separation unit 151 toward the second input unit 142 are at a predetermined ratio, for example, at a ratio of 1: 9 to 1:19. It is divided.
The first input unit 141, the second input unit 142, and the separation unit 151 are each composed of a beam splitter. When the first input unit 141, the second input unit 142, and the separation unit 151 are included in an optical system composed of an optical fiber, these elements are composed of an optical coupler. Further, the second input unit 142 may be composed of a circulator.

The optical wavelength tunable sensor 20 inputs the output light of the acoustic-optical wavelength tunable filter 12 via the second input unit 142, and emits the reflected light toward the second input unit 142. Here, the reflected light output by the light wavelength change type sensor 20 corresponds to a change in the physical quantity of the object to be measured in which the light wavelength change type sensor 20 is installed. Displacement, acceleration, inclination, strain, temperature, etc. can be exemplified as physical quantities of the object to be measured.
The divider 600 is output from the first divider 61, which receives signals output from the first receiver 31 and the reference light receiver 33, and the second receiver 32 and the reference light receiver 33, respectively. It is provided with a second divider 62 that receives a signal.

The measurement method in the third embodiment is the same as that in the first embodiment.
That is, the output light output from the acoustic-optical wavelength tunable filter 12 is branched into two by the separation unit 151. One of the two branched output lights is sent to the optical wavelength change type sensor 20 via the second input unit 142. The reflected light (λ ₁ , λ ₂ , ... λ _n ) from the optical wavelength change type sensor 20 passes through the second input unit 142 again and is received by the second light receiver 32 as measurement light. The measurement light is converted into a signal having a spectral waveform by the second receiver 32.
The other of the bifurcated output light is received by the reference light receiver 33 as reference light.
The signal output from the second light receiver 32 and the reference light receiver 33 is sent to the second divisor 62. The second divider 62 divides the output value of the signal output from the reference light receiver 33 by the output value of the signal output from the second receiver 32. That is, the second divider 62 functions as a differential amplifier, and is the spectral waveform of the acoustic-optical wavelength variable filter 12 obtained by the reference light receiver 33, and the light obtained by the second receiver 32. The spectrum of the reflected light from the wavelength change type sensor 20 is divided (measurement light / reference light). The principles of the first receiver 31, the reference light receiver 33, and the first divider 61 are also the same as those in FIGS. 3A to 3C. The first divider 61 is configured to divide the output value of the signal output from the first receiver 31 by the output value of the signal output from the reference light receiver 33.

In the third embodiment, the same effects as those in (1) to (6) of the first embodiment can be obtained, and the following effects can be obtained.
(8) The light receiver 30 for measurement light receives a first light receiver 31 that receives the reference light output from the reference wavelength generator 13 and a second light receiver that receives the output light output from the light wavelength change type sensor 20. Since it is configured separately from the device 32, it is possible to set the reference wavelength light and the output light output from the optical wavelength change type sensor to the same light wavelength band, and it is possible to perform a wide range of measurements with an accurate and simple structure. It can be carried out.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described with reference to FIG.
In the fourth embodiment, the configuration in which the input light is input to the acoustic-optical wavelength tunable filter 12 is different from that in the third embodiment, and the other configurations are the same as those in the third embodiment.
FIG. 9 shows a schematic configuration of the light wavelength measuring device 4.
In FIG. 9, in the optical wavelength measuring device 4, the input unit includes an optical amplifier 81 and a feedback unit 152 that returns the output light output from the acoustic-optical tunable filter 12 to the optical amplifier 81.

The optical amplifier 81 is composed of an erbium-doped fiber amplifier (EDFA) and a semiconductor optical amplifier (SOA).
The feedback unit 152 is composed of the same elements as the first input unit 141 and the second input unit 142, and returns the output light output from the acoustic-optical wavelength tunable filter 12 to the optical amplifier 81 and returns the output light to the first input unit 141. send.
In FIG. 9, the feedback unit 152 is arranged between the acoustic-optical wavelength tunable filter 12 and the first input unit 141, but in the present embodiment, the arrangement position of the feedback unit 152 is not limited. For example, the feedback unit 152 is between the first input unit 141 and the separation unit 151, between the separation unit 151 and the second input unit 142, or between the second input unit 142 and the optical wavelength change type sensor 20. It may be arranged in.

In the fourth embodiment, the same effects as those in (1) to (6) and (8) of the third embodiment can be obtained, and the following effects can be obtained.
(9) An input unit for inputting input light to the acoustic-optical wavelength variable filter 12 is provided with an optical amplifier 81 and a feedback unit 152 for returning the output light output from the acoustic-optical wavelength variable filter 12 to the optical amplifier 81. Because of the configuration, the intensity of light input to the reference wavelength generator 13 and the optical wavelength change type sensor 20 can be easily increased, and the wavelength sweep range can be further expanded.

[Fifth Embodiment]
Next, a fifth embodiment of the present invention will be described with reference to FIG.
In the fifth embodiment, the arrangement position of the optical amplifier 81 is different from that in the fourth embodiment, and other configurations are the same as those in the fourth embodiment.
FIG. 10 shows a schematic configuration of the light wavelength measuring device 5.
In FIG. 10, in the optical wavelength measuring device 5, the optical amplifier 81 constituting the input unit is arranged between the acoustic-optical wavelength tunable filter 12 and the feedback unit 152.
The feedback unit 152 returns the output light output from the acoustic-optical tunable filter 12 to the optical amplifier 81.
In the fifth embodiment, the same effects as in (1) to (6) (8) and (9) of the fourth embodiment can be obtained.

[Sixth Embodiment]
Next, the sixth embodiment of the present invention will be described with reference to FIG.
The sixth embodiment is different from the first embodiment in that the separation unit 151, the light receiver 33 for reference light, and the divider 600 are omitted, and other configurations are the same as those of the first embodiment. ..
FIG. 11 shows a schematic configuration of the light wavelength measuring device 6.
In FIG. 11, in the optical wavelength measuring device 6, the input unit 140 is arranged between the acoustic-optical wavelength variable filter 12 and the reference wavelength generator 13, and the reference wavelength light and the measurement light sent from the input unit 140 are the measurement light. It is sent to the receiver 30. The output signal from the light receiver 30 for measurement is sent to the wavelength calculation unit 63, and the wavelength calculation unit 63 calculates the measurement wavelength.
In the sixth embodiment, the same effects as those in (1) to (5) of the first embodiment can be obtained.

[7th Embodiment]
Next, a seventh embodiment of the present invention will be described with reference to FIG.
The seventh embodiment is different from the sixth embodiment in that the temperature detection unit 92 for the generator is omitted, and other configurations are the same as those of the sixth embodiment.
FIG. 12 shows a schematic configuration of the light wavelength measuring device 7.
In FIG. 12, in the optical wavelength measuring device 7, the temperature information of the reference wavelength generator 13 is not sent to the wavelength calculation unit 63.
In the seventh embodiment, the same effects as in (1), (3), and (5) of the first embodiment can be obtained.

[8th Embodiment]
Next, an eighth embodiment of the present invention will be described with reference to FIG.
In the eighth embodiment, the path through which the measurement light and the reference wavelength light enter the light receiver 30 for measurement light is different from that in the seventh embodiment, and other configurations are the same as those in the seventh embodiment.
FIG. 13 shows a schematic configuration of the light wavelength measuring device 8.
In FIG. 13, in the light wavelength measuring device 8, the reference wavelength generator 13 is arranged between the input unit 140 and the light receiver 30 for measurement light, and the light input from the input unit 140 to the reference wavelength generator 13 is a reference. It is sent to the receiver 30 for measurement light as wavelength light.
A beam splitter 153 is arranged inside the casing 11 between the input unit 140 and the optical wavelength change type sensor 20, and a beam splitter 154 is placed between the reference wavelength generator 13 and the light receiver 30 for measurement. It is placed inside. The light from the input unit 140 is sent to the light wavelength change type sensor 20 through the beam splitter 153, and the light reflected from the light wavelength change type sensor 20 is reflected by the beam splitter 153 and arranged inside the casing 11. It is sent as measurement light to the measurement light receiver 30 via the mirror 155 and the beam splitter 154.
In the eighth embodiment, the same effects as in (1), (3) and (5) of the first embodiment can be obtained.

[9th Embodiment]
Next, a ninth embodiment of the present invention will be described with reference to FIG.
In the ninth embodiment, the temperature detection unit 92 for the generator, the separation unit 151, and the light receiver 33 for reference light are omitted, and the position of the reference wavelength generator 13 is different from that of the first embodiment. The configuration of is the same as that of the first embodiment.
FIG. 14 shows a schematic configuration of the light wavelength measuring device 9.
In FIG. 14, in the optical wavelength measuring device 9, the input unit 140 is arranged inside the casing 11 between the acoustic-optical wavelength variable filter 12 and the optical wavelength change type sensor 20. The input unit 140 includes a first input unit 141 arranged on the acoustic-optical wavelength tunable filter 12 side and a second input unit 142 arranged on the optical wavelength tunable sensor 20 side. A reference wavelength generator 13 is arranged between the first input unit 141 and the light receiver 30 for measurement light. The light receiver 30 for measurement light is a first light receiver 31 arranged between the reference wavelength generator 13 and the divider 600, and a second receiver 30 arranged between the second input unit 142 and the divider 600. It has a vessel 32 and.
In the ninth embodiment, the same effects as those of (1), (3), (5) of the first embodiment and (8) of the third embodiment can be obtained.

[10th Embodiment]
Next, the tenth embodiment of the present invention will be described with reference to FIG.
The tenth embodiment is different from the ninth embodiment in that the temperature detection unit 92 for the generator is provided in the reference wavelength generator 13 of the ninth embodiment, and the other configurations are the same as those of the ninth embodiment. is there.
FIG. 15 shows a schematic configuration of the light wavelength measuring device 1A.
In FIG. 15, in the optical wavelength measuring device 1A, a generator temperature detecting unit 92 for detecting the temperature of the reference wavelength generator 13 is arranged inside the casing 11.
The temperature signal of the reference wavelength generator 13 detected by the temperature detection unit 92 for the generator is sent to the wavelength calculation unit 63.
In the tenth embodiment, the same effects as those of (1) to (6) of the first embodiment and (8) of the third embodiment can be obtained.

[11th Embodiment]
Next, the eleventh embodiment of the present invention will be described with reference to FIG.
The eleventh embodiment is different from the first embodiment in that the temperature detection unit 92 for the generator is omitted from the reference wavelength generator 13 of the first embodiment, and the other configurations are the same as those of the first embodiment. is there.
FIG. 16 shows a schematic configuration of the light wavelength measuring device 1B.
In FIG. 16, in the optical wavelength measuring device 1B, the generator temperature detecting unit 92 that detects the temperature of the reference wavelength generator 13 is omitted, and the wavelength calculation unit 63 measures the wavelength in a state where the temperature is not corrected. Will be done.
In the eleventh embodiment, the same effects as in (1), (3) to (6) of the first embodiment can be obtained.

The present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the range in which the object of the present invention can be achieved are included in the present invention.
For example, the acoustic-optical wavelength tunable filter 12 of the present invention is not limited to the waveguide type.

1,2,3,4,5,6,7,8,9,1A, 1B ... Optical wavelength measuring device, 12 ... Acoustic and optical wavelength variable filter, 13 ... Reference wavelength generator, 140 ... Input unit, 141 ... One input unit, 142 ... second input unit, 151 ... separation unit, 152 ... feedback unit, 20 ... optical wavelength change type sensor, 3A ... light receiving unit, 30 ... light receiver for measurement light, 31 ... first receiver, 32 ... Second receiver, 33 ... Reference optical receiver, 40 ... Control unit, 50 ... High frequency voltage generation circuit, 51 ... High frequency signal generator, 52 ... Amplifier, 60 ... Arithmetic circuit, 600 ... Divider, 61 ... No. One divider, 62 ... second divider, 63 ... wavelength calculation unit, 80 ... wideband light source, 81 ... optical amplifier, 91 ... filter temperature detector, 92 ... generator temperature detector

Claims (7)

An acoustic optic tunable filter that selectively extracts a predetermined wavelength from the input light,
A high-frequency voltage generation circuit that excites by applying a high-frequency signal to the acoustic-optical tunable filter,
A reference wavelength generator that outputs arbitrary reference wavelength light,
An optical wavelength change type sensor installed on the object to be measured and outputting light with a wavelength according to the physical quantity,
An input unit for inputting output light output from the acoustic-optical wavelength tunable filter to the reference wavelength generator and the optical wavelength tunable sensor, respectively.
A light receiver for measurement light that receives the output light output from the reference wavelength generator and also receives the output light output by the optical wavelength change type sensor via the input unit.
A reference light receiver that receives the output light output from the acoustic-optical tunable filter as reference light via a separation unit.
An arithmetic circuit that calculates the wavelength of the optical wavelength change type sensor based on the signals output from the measurement light receiver and the reference light receiver, and
A filter temperature detection unit that detects the temperature of the acoustic-optical tunable filter,
Optical wavelength measurement including a control unit that controls a frequency signal output by the high-frequency voltage generation circuit to the acoustic-optical wavelength variable filter based on a temperature signal output from the filter temperature detection unit. apparatus. In the light wavelength measuring apparatus according to claim 1,
A generator temperature detector for detecting the temperature of the reference wavelength generator is provided.
The arithmetic circuit includes an optical wavelength measuring unit that calculates the wavelength of output light output from the reference wavelength generator based on a temperature signal output from the generator temperature detecting unit. .. In the light wavelength measuring apparatus according to claim 1 or 2.
The optical amplifier arranged on the optical input side or the optical output side of the acoustic-optical wavelength variable filter, and the output light output from one of the acoustic optical wavelength variable filter and the optical amplifier are combined with the acoustic optical wavelength variable filter and the light. An optical wavelength measuring device characterized by having a feedback unit that feeds back to the other side of the amplifier. In the optical wavelength measuring apparatus according to any one of claims 1 to 3.
An optical wavelength measuring device characterized in that the acoustic-optical wavelength tunable filter and the filter temperature detecting unit are arranged in the same casing. In the light wavelength measuring apparatus according to any one of claims 2 to 4.
An optical wavelength measuring device characterized in that the acoustic-optical wavelength tunable filter and the reference wavelength generator are arranged in the same casing. In light wavelength measuring apparatus according to claim 5,
The optical wavelength measuring device is characterized in that the light receiver for measurement light is arranged in the same casing as the acoustic-optical wavelength tunable filter and the reference wavelength generator. An acoustic optic tunable filter that selectively extracts a predetermined wavelength from the input light,
A high-frequency voltage generation circuit that excites by applying a high-frequency signal to the acoustic-optical tunable filter,
A reference wavelength generator that outputs arbitrary reference wavelength light,
An optical wavelength change type sensor installed on the object to be measured and outputting light with a wavelength according to the physical quantity,
An input unit for inputting output light output from the acoustic-optical wavelength tunable filter to the reference wavelength generator and the optical wavelength tunable sensor, respectively.
A light receiver for measurement light that receives the output light output from the reference wavelength generator and also receives the output light output by the optical wavelength change type sensor via the input unit.
An arithmetic circuit that calculates the wavelength of the optical wavelength change type sensor based on the signal output from the measurement light receiver, and
A filter temperature detection unit that detects the temperature of the acoustic-optical tunable filter,
A control unit that controls a frequency signal output by the high-frequency voltage generation circuit to the acoustic-optical wavelength variable filter based on a temperature signal output from the filter temperature detection unit is provided.
The input unit is a first input unit that inputs the output light output from the acoustic-optical wavelength variable filter to the reference wavelength generator, and the optical wavelength change type that outputs the output light output from the acoustic-optical wavelength variable filter. It has a second input unit that allows the sensor to input.
The measurement light receiver receives the output light output from the reference wavelength generator and the output light output by the optical wavelength change type sensor via the second input unit. It has a second receiver that receives light,
Further, a reference light receiver that receives the output light output from the acoustic-optical wavelength variable filter, and the second input unit and the reference light receiver that receive the output light output from the acoustic-optical wavelength variable filter. Divide by dividing the output value of the signal output from at least one of the first receiver and the second receiver by the output value of the signal output from the separation unit and the reference optical receiver. An optical wavelength measuring device characterized by being equipped with a device.

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