JPH06120895A - Optical frequency discriminator - Google Patents

Abstract

(57) [Abstract] [Purpose] An optical frequency discriminating apparatus using an optical interferometer, which can be used by coupling the optical interferometer in both directions to reduce the number of uses. , It is intended to enable the efficiency of the optical axis adjustment work. [Structure] An optical interferometer 1 which outputs interference light according to an optical frequency discrimination characteristic with respect to input light, and light which is arranged on the same optical axis on both sides of the optical interferometer 1 is branched or combined or direction is changed. An optical frequency discriminating device is formed by the first and second optical input / output sections 2 and 3, and the optical frequency of the optical interferometer 1 with respect to the input light from one of the optical input / output sections 2 and 3, respectively. The output light is generated on the other side according to the frequency discrimination characteristic.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical frequency discriminating apparatus using an optical interferometer, and a laser optical frequency controlling apparatus using the optical frequency discriminating apparatus.

An optical interferometer has a characteristic that a pass band and a cutoff region are alternately repeated periodically with respect to input light.
As an optical frequency discriminator, which is used for various applications in the fields of measurement and communication using light,
The Fabry-Perot type optical interferometer and the Mach-Zehnder type optical interferometer are known. Optical interferometers are used for optical filters and switches in the field of communication, for example.

Optical interferometers are also used in optical frequency control of lasers. As one of such methods, there is a method of stabilizing the optical frequency by controlling other lasers with respect to a reference laser through an optical frequency discrimination characteristic of an optical interferometer. Such optical frequency control is applied to, for example, a distributed optical frequency division multiplexing (FDM) device that controls the optical frequencies of lasers in a plurality of optical transceivers with reference to a certain laser.

In these cases, the optical interferometer can be used by being bidirectionally coupled to it, so that the number of optical interferometers used can be halved and the efficiency of the optical axis adjustment work can be improved. Is required.

[0005]

2. Description of the Related Art FIG. 6 shows a conventional method of using an optical interferometer, where 11 is an optical interferometer, 12 is a laser diode (LD), and 13 is a light receiving element (PD) consisting of a photodiode. Is.

The optical interferometer 11 allows the light generated by the laser diode 12 to pass when the frequency of the light generated by the laser diode 12 corresponds to the pass band in the frequency discrimination characteristic. The light receiving element 13 receives the light and converts the light into an electric signal to generate an output signal.

FIG. 7 shows an optical frequency using a conventional optical interferometer.
It shows an example of a control device, which is parallel to an optical interferometer.
11 shows a case where light is input to the optical fiber, 11 is an optical interferometer, and 12_1,
12 ₂ Is a laser diode (LD), 13_1,Thirteen₂ Is
Photodiode (PD) consisting of photodiode, 14_1,14
₂ Is a control circuit.

The laser diode 12 ₁ generates reference light, and the laser diode 12 ₂ generates controlled light.
The light generated by the laser diodes 12 _{1 and} 12 ₂ is generated by the optical interferometer 1
1 is input in parallel. The output light of the optical interferometer 11 is added to the light receiving elements 13 _{1 and} 13 ₂ , respectively.

The light receiving element 13 ₁ is a laser diode 12
_By converting the output light of the optical interferometer 11 based on ₁ into an electrical signal, a detection signal that changes according to the frequency of the reference light from the laser diode 12 ₁ and the frequency discrimination characteristic of the optical interferometer 11 is generated. . The control circuit 14 ₁ changes the frequency discrimination characteristic of the optical interferometer 11 by controlling the distance between the parallel mirrors in the optical interferometer 11 in accordance with this detection signal by changing the temperature, the pressure, etc. The peak frequency is made to match the frequency of the reference light of the laser diode 12 ₁ .

On the other hand, the light receiving element 13 ₂ optically / electrically converts the output light of the optical interferometer 11 based on the laser diode 12 ₂ to obtain the frequency of the controlled light from the laser diode 12 ₂ and the optical interferometer 11 2. And a detection signal that changes in accordance with the frequency discrimination characteristic of. The control circuit 14 ₂ controls the oscillation frequency of the laser diode 12 ₂ in accordance with this detection signal so that the frequency of the controlled light coincides with the peak frequency of the optical interferometer 11.

Therefore, according to the optical frequency control device shown in FIG. 7, the frequency of the controlled light of the laser diode 12 ₂ is changed to the reference light of the laser diode 12 ₁ through the frequency discrimination characteristic of the optical interferometer 11. It is possible to follow this by controlling with the frequency of.

FIG. 8 shows an optical frequency using a conventional optical interferometer.
Fig. 7 shows another example of the control device, which is used for an optical interferometer.
The input and output optical paths are combined into one using an optical switch.
The case is shown. Same number as in Figure 7
, 13 is a light receiving element (P
D), 15 is an optical switch (or optical selector), 16 _1,
16₂ Is a sample and hold circuit.

The light receiving element 13 receives the output light of the optical interferometer 11.
The optical / electrical conversion is performed and the detection signal is supplied to the control circuit 14_1,14₂ To
input. The optical switch 15 is a laser diode 12_1,
12 ₂ The output light of the
Input and laser diode 12_1,12₂ Off
Sample and hold circuit 16 for replacement_1,16
₂ To maintain the output of the control circuit on the switched side.
Have it.

In the optical frequency controller of FIG. 8, control of the frequency discrimination characteristic of the optical interferometer 11 based on the reference light from the laser diode 12 ₁ and oscillation of the laser diode 12 ₂ based on the frequency discrimination characteristic of the optical interferometer 11 are performed. By performing the frequency control in a time-division manner, the optical paths of the input and output light with respect to the optical interferometer 11 can be unified.

FIG. 9 shows still another example of a conventional optical frequency control device using an optical interferometer, in which optical paths for input and output to and from the optical interferometer are combined into one using an optical coupler. It shows the case. The same components as those in FIG. 7 are designated by the same reference numerals, and 17 is an optical coupler.

The optical coupler 17 includes a laser diode 12₁ 
Output light and laser diode 12 ₂ Combine with the output light of
Then, it is input to the optical interferometer 11. The light receiving element 13 is
Generates a detection signal by converting the output light of the detector 11 from light to electricity
It

The control circuit 14 ₁ generates a synchronization signal composed of a frequency f _1, as well as modulating the reference light of the laser diode 12 _1, by synchronous detection output of the light receiving element 13 at a frequency f _1, the light A control signal for the interferometer 11 is generated. The control circuit 14 ₂ generates a synchronization signal having a frequency f ₂ to modulate the controlled light of the laser diode 12 ₂ and at the same time synchronously detects the output of the light receiving element 13 at the frequency f _2.
Generate a control signal for 2 ₂ .

In the optical frequency control device of FIG. 9, control of the frequency discrimination characteristic of the optical interferometer 11 based on the reference light from the laser diode 12 ₁ and oscillation of the laser diode 12 ₂ based on the frequency discrimination characteristic of the optical interferometer 11 are performed. The control of the frequency is separated by the coherent detection of different frequencies and separately performed, so that the optical paths of the input and output lights to the optical interferometer 11 can be made one.

[0019]

In the conventional method of using the optical interferometer and the optical frequency control device using the optical interferometer, only one light is input to one input / output optical path of the optical interferometer. The principle is to apply, and in the case of applying two or more lights, they had to be input in parallel at different positions of the optical interferometer. However, even if the same optical interferometer is used, if different positions are used, it is not guaranteed that the frequency discrimination characteristics are the same, and there is a possibility that correct control may not be performed. .

Further, if one input / output optical path is used in a time-divisional manner, or if a method of modulating by using different frequencies and separating by synchronous detection is used, a plurality of input / output optical paths can be obtained. It is possible to apply the light of
In such a case, there is a problem in that the device becomes inevitably large and complicated, and becomes expensive.

The present invention is intended to solve the above-mentioned problems of the prior art, in which light is transmitted in both directions to the optical interferometer, so that the optical interferometer is provided with one input. An optical frequency discriminating device and an optical frequency control device, which can apply two lights to the output optical path and therefore can reduce the number of optical interferometers to be used by half and enable efficient optical axis adjustment work. The purpose is to provide a device.

[0022]

(1) An optical frequency discriminating apparatus according to the present invention comprises an optical interferometer 1 for outputting interference light according to an optical frequency discriminating characteristic with respect to input light, and both sides of the optical interferometer 1. Has first and second light input / output units 2 and 3 for branching, synthesizing, or changing the direction of lights arranged on the same optical axis. With respect to the input light, the output light is generated to the other according to the optical frequency discrimination characteristic of the optical interferometer 1.

(2) Further, in the optical frequency discriminating device of (1), the present invention modulates the light passing through the optical interferometer 1 at a frequency f, and at the same time, a reference light coupled to one optical input / output unit 2. A laser diode 4 ₁ for generating light, a light receiving element 5 ₁ coupled to the other optical input / output unit 3, and a first synchronous detection circuit 6 for generating a signal obtained by synchronously detecting the output of the light receiving element 5 _{1 at} a frequency f. _1, provided with an optical interference control part consisting of a first operating point setting circuit 7 Tokyo _and changing the frequency discrimination characteristic of the optical interferometer 1 in accordance with the output of the synchronous detection circuit _61, the optical interferometer 1
Together with to follow the reference light frequency discrimination characteristic, the other of the laser diode 4 ₂ for generating the controlled light coupled into the light input and output section 3, a light receiving element coupled to one optical input-output section 2 5 ₂ and the output of the light receiving element 5 ₂ are frequency f
Second synchronous detection circuit 6 ₂ which generates a signal synchronously detected by
When, the changes the oscillation frequency of the laser diode 4 ₂ generates a control signal in accordance with the output of the synchronous detection circuit 6 ₂ 2
The operating point setting circuit 7 ₂ and the laser diode control section are provided, and the frequency of the controlled light is made to follow the optical frequency discrimination characteristic of the optical interferometer 1. Stabilize by.

(3) Further, in the optical frequency control device of (2), the present invention provides a plurality of laser diodes 4 _21, 4 _22, 4 _23, ... Which generate controlled light and a plurality of laser diodes 4
_The optical selector 10 for selecting the optical outputs of _21, 4, _22, 4 _23, ... In a time division manner and coupling them to one optical input / output unit 3 and the control signal of the operating point setting circuit 7 ₂ are selected by the optical selector 10. , And a plurality of sample-hold circuits 9 _1, 9 _2, 9 _3, which hold the distribution output of the selector 8 and supply it to the laser diodes 4 _21, 4 _22, 4 _{23 ,} . , And stabilize the frequencies of a plurality of controlled lights by the same reference light.

[0025]

FIG. 1 shows a principle configuration (1) of the present invention, and shows an optical frequency discriminating apparatus using an optical interferometer. In the figure, 1 is an optical interferometer, and 2 and 3 are optical input / output units including optical couplers, optical circulators, and the like.

The optical input / output units 2 and 3 are for branching, multiplexing, or changing the direction of light, such as an optical coupler and an optical circulator, and have the same optical axis of the optical interferometer 1. It is provided on one side of the upper side and the other side.

In the optical frequency discriminator shown in FIG. 1, since the optical input / output units 2 and 3 are provided at one port of the same optical path of the optical interferometer 1 and at the port on the opposite side, By the same optical path of the optical interferometer 1, it is possible to input / output light to / from the interferometer 1 from any direction and obtain an optical frequency discrimination characteristic.

FIG. 2 shows a principle structure (2) of the present invention, and shows an optical frequency discriminating device using an optical interferometer. In the figure, the same elements as those in FIG. 1 are designated by the same reference numerals, 2 _1, 2 ₂ and 3 _1, 3 ₂ are optical couplers,
An optical input / output unit including an optical circulator and the like.

The optical input / output units 2 _1, 3 ₁ are provided at one port of the optical path where the optical interferometer 1 is located and at the port on the opposite side thereof, and the optical coupling units 2 _2, 3 ₂ are It is provided at one port of the other optical path of the interferometer 1 and at the port on the opposite side.

In the optical frequency discriminator shown in FIG. 2, the optical coupling sections 2 _1, 3 ₁ and 2 _2, 3 ₂ are provided at one port of the same optical path of the optical interferometer 1 and at the opposite side. Since it is provided in the port, the two optical paths of the optical interferometer 1 are independent of each other, with respect to the interferometer 1 from any direction.
By inputting and outputting light, the optical frequency discrimination characteristics can be obtained respectively.

FIG. 3 shows the basic configuration (3) of the present invention.
And an optical frequency controller using an optical interferometer
Shows. The same items as in Fig. 2 are indicated by the same numbers.
Then 4 _1,Four₂ Is a laser diode (LD), 5_1,5₂ Is
Photodetector (PD) consisting of photodiode, 6_1,6₂ 
Is a synchronous detection circuit, 7_1,7_2,Is an operating point setting circuit. Receiving
Optical element 5_1,Synchronous detection circuit 6_1,Operating point setting circuit 7₁ Is light dried
An optical interferometer control unit for controlling the interrogator 1 is configured, and the light receiving element 5
_2,Synchronous detection circuit 6_2,Operating point setting circuit 7₂ Laser dio
Mode 4₂ A laser diode controller that controls
There is.

The laser diode 4 ₁ generates reference light, and the laser diode 4 ₂ generates controlled light. The light generated by the laser diode 4 ₁ is input to the optical interferometer 1 via the optical input / output unit 2, and the output light of the optical interferometer ₁ is added to the light receiving element 5 ₁ . Generating light from the laser diode 4 _2,
The light is input to the optical interferometer 1 via the optical input / output unit 3, and the optical interferometer 1
The output light is applied to the light receiving element 5 _2. Optical interferometer 1
Has its pass characteristic modulated at a frequency f, and therefore, the passing light becomes a modulated light having a frequency f. The modulation of the light passing through the optical interferometer 1 is not limited to the optical interferometer 1 and may be performed in another portion.

The light receiving element 5 ₁ generates a signal obtained by optoelectrically converting the output light of the optical interferometer 1 based on the laser diode 4 ₁ . The synchronous detection circuit 6 ₁ synchronously detects this signal at the frequency f, so that the frequency of the reference light from the laser diode 4 ₁ is higher or lower than the peak frequency of the frequency discrimination characteristic of the optical interferometer 1. Generates a signal whose polarity changes. The operating point setting circuit 7 ₁ controls the distance between the parallel mirrors in the optical interferometer 1 by changing the temperature, the pressure, etc. in accordance with this signal, and thus the optical interferometer 1
By changing the frequency discrimination characteristic of, the peak frequency is
So as to follow the frequency of the laser diode 4 ₁ of the reference light.

On the other hand, the light receiving element 5 ₂ generates a signal obtained by optoelectrically converting the output light of the optical interferometer 1 based on the laser diode 4 ₂ . The synchronous detection circuit 6 ₂ detects the laser diode 4 ₂ by synchronously detecting this signal at the frequency f.
A signal whose polarity changes depending on whether the frequency of the controlled light from is higher or lower than the peak frequency of the frequency discrimination characteristic of the optical interferometer 1 is generated. Operating point setting circuit 7 _2,
By controlling the oscillation frequency of the laser diode 4 ₂ in response to this signal, the optical interferometer 1 the frequency of the controlled light
Follow the peak frequency of.

Therefore, according to the frequency control device shown in FIG. 3, the frequency of the controlled light of the laser diode 4 ₂ is set to the reference light of the laser diode 4 ₁ through the frequency discrimination characteristic of the optical interferometer 1. It can be controlled on the basis of frequency.

FIG. 4 shows the principle configuration (4) of the present invention.
And an optical frequency controller using an optical interferometer
Shows. The same items as in Fig. 3 are indicated by the same numbers.
Then 4 _{twenty one}, 4_{twenty two}, 4_{twenty three,}... is a laser that emits controlled light
Diode, 8 is selector, 9 _1,9_2,9_3,… Is a sample
-Hold circuit 10 is an optical selector.

The laser diode 4 ₁ generates reference light and inputs it to the optical interferometer 1 via the light input / output unit 2. The output light of the optical interferometer ₁ is added to the light receiving element 5 ₁ . The light receiving element 5 ₁ generates a signal obtained by optoelectrically converting the output light of the optical interferometer 1. The synchronous detection circuit 6 ₁ generates an output by synchronously detecting this signal at the frequency f, and the operating point setting circuit 7 ₁ controls the optical interferometer 1 according to this signal to change its frequency discrimination characteristic. As in the case of FIG. 3, the peak frequency of the optical interferometer 1 is controlled so as to follow the frequency of the reference light of the laser diode 4 ₁ .

Laser diodes 4 ₂₁ , 4 ₂₂ , 4 _23, ...
Generates controlled light. The optical selector 10 sequentially selects the output light of the laser diodes 4 ₂₁ , 4 ₂₂ , 4 _23, ... In a time-divisional manner and inputs the output light to the optical interferometer 1 via the optical coupler 3.
The output of the optical interferometer 1 is applied to the light receiving element 5 ₂ via the optical coupler 2.

The light receiving element 5 ₂ generates light / electrical conversion signal of the output light of the optical interferometer 1 based on the laser diode which is selected by the optical selector 10. The synchronous detection circuit 6 ₂ generates an output by synchronously detecting this signal at the frequency f, and the operating point setting circuit 7 ₂ generates a control signal for controlling the oscillation frequency of the laser diode according to this signal.

The selector 8 selects the control signal output from the operating point setting circuit 7 _{2 according} to the selection of the optical selector 10, and the sample and hold circuits 9 _1, 9 _2, 9 respectively.
Enter in _3, ... Sample and hold circuit 9 _1, 9 _2, 9 _3,
, Hold the input control signals and supply them to the laser diodes 4 ₂₁ , 4 ₂₂ , 4 _{23 ,} . Thereby, the oscillation frequency of each laser diode is controlled so as to follow one of the peak frequencies of the optical interferometer 1.

Therefore, according to the frequency control device shown in FIG. 4, the laser diodes 4 ₂₁ , 4 ₂₂ and 4 ₂₂ are connected via the peak frequency in the frequency discrimination characteristic of the optical interferometer 1.
4 _23, ... of the frequency of the controlled light, the laser diode 4 ₁
It is possible to control by using the frequency of the reference light of.

[0042]

FIG. 5 shows an embodiment of the present invention, which is applied to a dispersion type optical FDM apparatus.
S1, OS2, OS3, ... Are transmitters, OR1, OR2,
OR3, ... Are receivers, 18 is a star coupler, and 19 is a laser diode (LD) that generates reference light. In FIG. 5, only the transmitting unit OS1 and the receiving unit OR1 are shown as typical configurations, but the configurations of the other transmitting units and receiving units are similar.

In the transmitter OS1, 21 is an optical coupler,
Reference numeral 22 is an optical coupler, 22A is an optical circulator, 23 is an optical interferometer, 24 is an optical coupler, 25 is a light receiving element (PD) including a photodiode, 26 is a synchronous detection circuit, and 27 is a signal of the modulation frequency f for synchronous detection. An oscillator for generating, an adding circuit (+) 28, a laser diode (LD) 29 for generating controlled light, a light receiving element (PD) 30 including a photodiode, 31 a synchronous detection circuit, and 32 lithium niobate. It is an external modulator made of crystal or the like. In the receiving unit OR1, 33 is a tunable optical filter, and 34 is
Is the receiver.

The star coupler 18 is the laser diode 1
9 are input in parallel to the respective transmitters OS1, OS2, OS3, ..., and the outputs of the respective transmitters OS1, OS2, OS3 ,. Send out.

In the transmitter OS1, the star coupler 18
The reference light from the optical coupler 21 and the optical circulator 22 are
It is added to the optical interferometer 23 via A. The output light of the optical interferometer 23 is applied to the light receiving element 25 via the optical coupler 24. The light receiving element 25 converts the input light from the optical coupler 24
Generates electrical converted signals. The synchronous detection circuit 26 synchronously detects this signal at the frequency f to generate a control signal whose polarity changes according to the frequency of the reference light from the laser diode 19 and the peak frequency of the frequency discrimination characteristic of the optical interferometer 23. Occur.

The adder circuit 28 superimposes the control signal from the synchronous detection circuit 26 on the modulated signal for synchronous detection from the oscillator 27 and adds the control signal to the optical interferometer 23 to output the output light of the optical interferometer 23 to the frequency. Modulate with f. At this time, the control signal from the synchronous detection circuit 26 is given as a bias signal, so that the frequency discrimination characteristic of the optical interferometer 23 changes, so that the peak frequency of the frequency discrimination characteristic of the optical interferometer 23 changes to the laser diode 19 It is controlled so as to follow the reference frequency of.

On the other hand, the output light of the laser diode 29 is
It is added to the optical interferometer 23 via the optical coupler 22 and the optical coupler 24. The output of the optical interferometer 23 is the optical circulator 22.
It is added to the light receiving element 30 via A. The light receiving element 30 is
The input light from the optical circulator 22A is photo-electrically converted to generate a signal. The synchronous detection circuit 31 synchronously detects this signal at the frequency f, so that the polarity changes according to the frequency of the controlled light from the laser diode 29 and the peak frequency of the frequency discrimination characteristic of the optical interferometer 23. To occur. Since the oscillation frequency of the laser diode 29 is controlled by this signal, the frequency of its output light follows one of the peak frequencies of the frequency discrimination characteristics of the optical interferometer 23, and the laser diode 19 has a reference frequency. Stabilized by the frequency of light.

The light generated by the laser diode 29 is input to the external modulator 32 via the optical coupler 22, modulated by the signal of the information to be transmitted, output via the optical coupler 21 and transmitted via the star coupler 18. It

In the receiving section OR1, the tunable optical filter 33 selectively passes the light generated by the laser diode 29 and inputs it to the receiver 34. The receiver 34 is
The reception function demodulates the modulated signal of the transmitter OS1 and receives it.

The operations of the other transmitters OS2, OS3, ... And the receivers OR2, OR3 ,. At this time, by arbitrarily selecting the relationship between the plurality of pass bands of the optical interferometer in each transmitting unit and the reference optical frequency and the controlled optical frequency, it is possible to generate optical signals of a plurality of different frequencies, For example, an optical FDM device can be easily configured, but as is clear from the above description, in this embodiment, only one laser diode is required to generate the reference light, so that the device can be simplified and downsized. The price can be reduced.

[0051]

As described above, according to the present invention, the manufacture of an optical interferometer is facilitated and its effective use becomes possible, and in a system using the optical interferometer,
The device can be simplified, miniaturized, and highly reliable, which contributes to the cost reduction.

[Brief description of drawings]

FIG. 1 is a diagram showing a basic configuration (1) of the present invention.

FIG. 2 is a diagram showing a basic configuration (2) of the present invention.

FIG. 3 is a diagram showing a principle configuration (3) of the present invention.

FIG. 4 is a diagram showing a principle configuration (4) of the present invention.

FIG. 5 is a diagram showing an embodiment of the present invention.

FIG. 6 is a diagram showing a method of using a conventional optical interferometer.

FIG. 7 is a diagram showing an example of a conventional optical frequency control device using an optical interferometer.

FIG. 8 is a diagram showing another example of a conventional optical frequency control device using an optical interferometer.

FIG. 9 is a diagram showing still another example of an optical frequency control device using a conventional optical interferometer.

[Explanation of symbols]

1 Optical interferometer 2 Optical input / output unit 3 Optical input / output unit 4 ₁ Laser diode 4 ₂ Laser diode 4 _21, 4 _22, 4 _23, ... Laser diode 5 ₁ Photodetector 5 ₂ Photodetector 6 ₁ Synchronous detection circuit 6 ₂ Synchronous Detection circuit 7 ₁ Operating point setting circuit 7 ₂ Operating point setting circuit 8 Selector 9 _1, 9 _2, 9 _3, ... Sample and hold circuit 10 Optical selector

Claims (3)

[Claims] 1. An optical interferometer (1) for outputting interference light according to an optical frequency discrimination characteristic with respect to input light, and light arranged on the same optical axis on both sides of the optical interferometer (1). A first and a second optical input / output unit (2, 3) for branching, combining, or changing the direction, and for input light from one of the optical input / output units (2, 3), An optical frequency discriminating device, wherein output light is generated to the other according to the optical frequency discriminating characteristic of the optical interferometer (1). 2. The optical frequency discriminating device according to claim 1.
The light passing through the optical interferometer (1) at a frequency (f).
And to generate the reference light coupled to one of the light input / output units (2)
Laser diode (4 ₁ ) And a light receiving element (5) coupled to the other optical input / output section (3).₁ )
And the light receiving element (5₁) Output at the same frequency (f)
A first synchronous detection circuit (6₁ )
And the synchronous detection circuit (6₁ ) Optical interference depending on the output of
First operating point setting for changing the frequency discrimination characteristic of the device (1)
Constant circuit (7₁ ) And an optical interferometer controller consisting of
The frequency discrimination characteristic of the optical interferometer (1) is compared with the reference light.
The controlled light coupled to the other optical input / output unit (3).
Laser diode (4₂ ) And a light receiving element (5) coupled to the one optical input / output unit (2).
₂ ) And the light receiving element (5₂ ) Output from the frequency (f)
A second synchronous detection circuit (6 that generates a signal synchronously detected by
₂ ) And the synchronous detection circuit (6₂ ) Control signal according to the output of
The laser diode (4₂ ) Oscillation frequency
Second operating point setting circuit (7 ₂ ) Consists of
A laser diode controller is provided to control the frequency of the controlled light.
The number to the optical frequency discrimination characteristics of the optical interferometer (1).
By making the frequency of the controlled light
Optical frequency control device characterized by being stabilized by light
Place 3. The optical frequency control device according to claim 2, wherein a plurality of laser diodes (4) for generating controlled light are generated.
_21, 4 _22, 4 _23, ...) And the optical outputs of the plurality of laser diodes (4 _21, 4 _22, 4 _23, ...) Are selected in a time division manner, and the one optical input / output unit (3) is selected. To the optical selector (10), a selector (8) that distributes the control signal of the operating point setting circuit (7 ₂ ) in synchronization with the selection of the optical selector (10), and a distribution of the selector (8). the hold output the laser diodes (4 _21, 4 _22, 4 _23, ...) a plurality of sample and hold circuits and supplies (9 _1, 9 _2, 9 _3, ...)
An optical frequency control device comprising: and stabilizing the frequencies of a plurality of controlled lights by the same reference light.