CN113541781A - Laser frequency detection device and method - Google Patents

Laser frequency detection device and method Download PDF

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Publication number
CN113541781A
CN113541781A CN202010308589.7A CN202010308589A CN113541781A CN 113541781 A CN113541781 A CN 113541781A CN 202010308589 A CN202010308589 A CN 202010308589A CN 113541781 A CN113541781 A CN 113541781A
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interferometer
light
phase change
change value
measured
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艾凡
苏玉锋
陈飞
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Huawei Technologies Co Ltd
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
    • H04B10/075—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal
    • H04B10/079—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal using measurements of the data signal
    • H04B10/0795—Performance monitoring; Measurement of transmission parameters
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for

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  • Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)

Abstract

The application relates to a laser frequency detection device and a method, wherein the device comprises a first interferometer, a second interferometer and a demodulator, the first interferometer is packaged by materials with a temperature coefficient being a first coefficient, and the second interferometer is packaged by materials with a temperature coefficient being a second coefficient; the phase change value of the first light to be measured caused by the first interferometer is a first phase change value, the phase change value of the second light to be measured caused by the second interferometer is a second phase change value, the first light to be measured is a beam of light emitted by the laser source to be measured, and the second light to be measured is another beam of light emitted by the laser source to be measured or light output from the first interferometer; and the demodulator determines the frequency of the light emitted by the laser source to be detected according to the first coefficient, the second coefficient, the first phase change value and the second phase change value.

Description

Laser frequency detection device and method
Technical Field
The present disclosure relates to the field of optical communications, and in particular, to a laser frequency detection apparatus and method.
Background
The laser is widely applied to the fields of photoelectric measurement, optical communication and the like, and an output optical signal is modulated, transmitted and received, so that a large amount of information can be borne. The laser is usually output in a single longitudinal mode, and the output spectrum is limited to a specific waveband after modulation. As used in wavelength division multiplexing systems, the center wavelength of the laser is typically considered a stable parameter and matched to the passband range of the link filter. The output light frequency of the laser is closely related to the acquisition of laser bearing information, and factors such as environmental temperature fluctuation, driving current instability, nonlinear effect inside the laser and the like can cause the change and jitter of the output light frequency of the laser. Laser frequency variations can cause overall spectral drift of the optical signal transmitted by the fiber, causing it to mismatch with the link filter device and thereby introducing additional loss. Therefore, a laser frequency detection device is required to detect a change in laser frequency, and to cope with and adjust in time.
In the photoelectric measurement system, the change of the laser frequency is also loaded on the measurement parameter, which causes the inaccuracy of the measurement result. In high precision measurement applications, high stability of laser frequency is a guarantee of measurement precision. The existing laser frequency detection device is limited in measurement range, poor in structural stability, easy to be influenced by temperature and environmental vibration, and large in measurement error.
Disclosure of Invention
In view of this, the embodiment of the present application provides a device and a method for detecting a laser frequency, which improve the precision of laser frequency measurement and have high stability.
In a first aspect, an embodiment of the present application discloses a laser frequency detection apparatus, including:
the system comprises at least two interferometers and a demodulator, wherein the at least two interferometers comprise a first interferometer and a second interferometer, the first interferometer is packaged by a material with a temperature coefficient being a first coefficient, and the second interferometer is packaged by a material with a temperature coefficient being a second coefficient;
the interferometer is used for changing the phase of light emitted by a laser source to be measured, the phase change value of first light to be measured caused by the first interferometer is a first phase change value, the phase change value of second light to be measured caused by the second interferometer is a second phase change value, the first light to be measured is one beam of light emitted by the laser source to be measured, and the second light to be measured is the other beam of light emitted by the laser source to be measured or light output from the first interferometer;
the demodulator is used for determining the frequency of the light emitted by the laser source to be measured according to the first coefficient, the second coefficient, the first phase change value and the second phase change value.
The refractive index of the waveguide material (excluding the encapsulation material) constituting the first interferometer and the second interferometer is the same, and generally, the waveguide material refers to the waveguide material actually related to the cavity length Δ L in the interferometer.
In one possible design, the laser frequency detection device further includes a first beam splitter, where the first beam splitter is configured to split a beam of light emitted by the laser source to be detected to obtain the first light to be detected and the second light to be detected; the first interferometer is used for changing the phase of the first light to be detected; the second interferometer is used for changing the phase of the second light to be measured.
In one possible design, the laser frequency detection device further includes a circulator and a modulator; the modulator is used for performing pulse modulation on a beam of light emitted by the laser source to be detected and shifting frequency to obtain first light to be detected;
the circulator is used for receiving the first to-be-detected light and outputting the first to-be-detected light to the first interferometer;
the first interferometer is used for changing the phase of the first light to be measured to obtain second light to be measured;
the second interferometer is used for receiving second light to be measured and changing the phase of the second light to be measured to obtain third light to be measured;
the circulator is also used for receiving the third light to be detected and outputting the third light to the demodulator.
In one possible design, the first phase change value includes a first sub-phase change value caused by a frequency of the first light to be detected in the first interferometer and a second sub-phase change value caused by an ambient temperature in which the first interferometer is located, the second sub-phase change value being related to the first coefficient;
the second phase change value includes a third sub-phase change value caused by the frequency of the second light to be measured in the second interferometer and a fourth sub-phase change value caused by the ambient temperature in which the second interferometer is located, and the fourth sub-phase change value is related to the second coefficient.
In one possible design, the demodulator is configured to determine the frequency of light emitted by the laser source to be measured according to a first coefficient, a second coefficient, a first sub-phase change value, a second sub-phase change value, a third sub-phase change value, a fourth sub-phase change value, a first phase change value, a second phase change value, a cavity length of the first interferometer and a cavity length of the second interferometer, where the cavity length is a difference between lengths of two waveguides in the interferometer that are used to transmit optical signals.
In one possible design, the laser frequency detection apparatus further includes a reflection member for reflecting the first light to be measured that has passed through the first interferometer and the second light to be measured that has passed through the second interferometer to the demodulator.
In one possible design, the first interferometer or the second interferometer is any one of the following interferometers: fabry-perot (FP) interferometer, Mach-Zehnder (Mach-Zehnder) interferometer, Michelson (Michelson) interferometer, or Sagnac (Sagnac) interferometer.
In one possible design, the modulator is an acousto-optic modulator or an electro-optic modulator.
In a second aspect, an embodiment of the present application discloses a laser frequency detection method, including:
splitting the light to be measured to obtain a first light to be measured and a second light to be measured;
the first interferometer receives first to-be-detected light, the first interferometer is packaged by a material with a temperature coefficient being a first coefficient, and a phase change value of the first to-be-detected light caused by the first interferometer is a first phase change value;
the second interferometer receives second light to be measured, the second interferometer is packaged by materials with a second coefficient of temperature coefficient, and the phase change value of the second light to be measured caused by the second interferometer is a second phase change value;
and determining the frequency of the light to be measured according to the first coefficient, the second coefficient, the first phase change value and the second phase change value.
In one possible design, the first phase change value includes a first sub-phase change value caused by a frequency of the first light to be detected in the first interferometer and a second sub-phase change value caused by an ambient temperature in which the first interferometer is located, the second sub-phase change value being related to the first coefficient;
the second phase change value includes a third sub-phase change value caused by the frequency of the second light to be measured in the second interferometer and a fourth sub-phase change value caused by the ambient temperature in which the second interferometer is located, and the fourth sub-phase change value is related to the second coefficient.
In one possible design, the frequency of light to be measured is determined according to the first coefficient, the second coefficient, the first sub-phase change value, the second sub-phase change value, the third sub-phase change value, the fourth sub-phase change value, the first phase change value, and the second phase change value.
In a third aspect, an embodiment of the present application further discloses a laser frequency detection method, including:
modulating the light to be measured to obtain first light to be measured;
the first interferometer changes the phase of the first to-be-detected light and obtains a second to-be-detected light, the first interferometer is packaged by a material with a temperature coefficient being a first coefficient, and the phase change value of the first to-be-detected light caused by the first interferometer is a first phase change value;
the second interferometer receives second light to be measured, the second interferometer is packaged by materials with a second coefficient of temperature coefficient, and the phase change value of the second light to be measured caused by the second interferometer is a second phase change value;
and determining the frequency of the light to be measured according to the first coefficient, the second coefficient, the first phase change value and the second phase change value.
In one possible design, the first phase change value includes a first sub-phase change value caused by a frequency of the first light to be detected in the first interferometer and a second sub-phase change value caused by an ambient temperature in which the first interferometer is located, the second sub-phase change value being related to the first coefficient;
the second phase change value includes a third sub-phase change value caused by the frequency of the second light to be measured in the second interferometer and a fourth sub-phase change value caused by the ambient temperature in which the second interferometer is located, and the fourth sub-phase change value is related to the second coefficient.
In one possible design, the frequency of light to be measured is determined according to the first coefficient, the second coefficient, the first sub-phase change value, the second sub-phase change value, the third sub-phase change value, the fourth sub-phase change value, the first phase change value, and the second phase change value.
In a fourth aspect, an embodiment of the present application discloses a laser frequency detection system, which includes a laser, a second beam splitter, and any one of the laser frequency detection devices in the first aspect;
the laser is used for emitting laser;
the second optical splitter is used for coupling out a part of laser as a service signal, coupling out the other part of laser as light to be detected, and outputting the light to be detected to the laser frequency detection device.
The application discloses laser frequency detection device measures through the interferometer of the material encapsulation that introduces two kinds of different temperature coefficients, and the effectual temperature of having avoided measures the error that brings to laser frequency, and stability is high.
Drawings
Fig. 1 is a schematic structural diagram of a conventional laser frequency detection device;
fig. 2 is a schematic diagram of a laser frequency detection apparatus 200 according to an embodiment of the present application;
fig. 3 is a schematic diagram of a laser frequency detection apparatus 300 according to an embodiment of the present disclosure;
FIG. 4 is a diagram of an interferometer according to an embodiment of the present disclosure;
fig. 5 is a schematic diagram of a laser frequency detection apparatus 500 according to an embodiment of the present disclosure;
fig. 6 is a schematic diagram of a laser frequency detection apparatus 600 according to an embodiment of the present disclosure;
fig. 7 is a schematic diagram of a laser frequency detection apparatus 700 according to an embodiment of the present application
Fig. 8 is a schematic diagram of a laser frequency detection system according to an embodiment of the present application.
Detailed Description
Fig. 1 is a schematic structural diagram of a conventional laser frequency detection device. The laser frequency detection device includes a laser 101, a reference light source 102, a coupler 103, a detector 104, and a spectrum detector 105. Laser light output by the laser 101 and reference light output by the reference light source 102 are coupled by the coupler 103 and then received by the detector 104, and the spectrum detector 105 detects the spectrum of the coupled light, so that the frequency difference between the laser light output by the laser 101 and the reference light can be obtained, and the detection of the frequency change of the laser can be realized. Although the scheme can directly measure the frequency change of the laser, the method seriously depends on the stability and the accuracy of the frequency of the reference light source, and the bandwidth of the reference light source and the frequency spectrum detector also limits the measuring range of the frequency deviation of the laser.
The superposition of two lines of quasi-monochromatic light with a fixed phase difference of the interferometer will result in a change of the amplitude, so that phase information of the light can be obtained by measuring the amplitude of the light more easily. In general, interferometers produce a phase change to incident light
Figure BDA0002456742370000031
By two parts
Figure BDA0002456742370000032
And
Figure BDA0002456742370000033
and (4) forming. The first part
Figure BDA0002456742370000034
Is a phase change introduced by a frequency change of an interferometer, the interferometer introducing a phase change to an optical signal passing through it
Figure BDA0002456742370000035
And the frequency f of the optical signal
Figure BDA0002456742370000036
(n is the refractive index of the waveguide material in the interferometer, c is the speed of light in vacuum), (1)
I.e. the phase introduced by the interferometer due to the laser frequency f for light of the same frequency, without taking into account other factors than the frequency of the optical signal
Figure BDA0002456742370000037
In a positive correlation with the cavity length Δ L of the interferometer, where the cavity length Δ L is typically the difference in path length of the optical signal transmitted within the interferometer (there are two differences in a typical interferometer)Optical signal of). The second part is
Figure BDA0002456742370000038
Is the phase change of light caused by interferometer caused by temperature T, the interferometer can be packaged by material with temperature coefficient K, and the phase change of light caused by interferometer caused by temperature T is characterized by the temperature coefficient K
Figure BDA0002456742370000039
The encapsulation material of the interferometer may be a resin, a heat shrink, or the like.
Fig. 2 is a laser frequency detection apparatus 200 according to an embodiment of the present application. As shown in fig. 2, the laser frequency detection apparatus 200 includes an interferometer system 201 and a demodulator 202. The interferometer system comprises at least two interferometers including a first interferometer and a second interferometer, wherein the first interferometer has a temperature coefficient of a first coefficient K1The second interferometer is encapsulated by a material with a temperature coefficient of a second coefficient K2The material of (2) is encapsulated.
The refractive indexes of waveguide materials (excluding packaging materials) forming the first interferometer and the second interferometer are the same, and generally, the waveguide materials refer to waveguide materials actually related to the calculation of the cavity length delta L in the interferometers, namely waveguide materials actually participating in the transmission of optical signals in the interferometers. The length of the cavity is also the difference between the lengths of two waveguides in the interferometer for transmitting two optical signals respectively.
Light emitted by the laser source to be measured is incident on the interferometer system 201, and the interferometer system 201 changes the phase of the light emitted by the laser source to be measured. Wherein the phase change value of the first to-be-detected light caused by the first interferometer is the first phase change value
Figure BDA0002456742370000042
The phase change value of the second light to be detected caused by the second interferometer is a second phase change value
Figure BDA0002456742370000043
The demodulator 202 is used for changing the value according to the first phase
Figure BDA0002456742370000044
And a second phase change value
Figure BDA0002456742370000045
And determining the frequency f of the light to be measured. Wherein the length of the cavity of the first interferometer is Delta L1The length of the cavity of the second interferometer is DeltaL2The first light to be measured is one beam of light emitted by the laser source to be measured, and the second light to be measured is the other beam of light emitted by the laser source to be measured or the light output from the first interferometer.
It should be noted that the light to be measured passing through the first interferometer and the second interferometer may be the same light, or may be two beams of laser light whose power is split. When the first interferometer and the second interferometer are measuring the laser frequency, the optical power passing through the first interferometer and the second interferometer is not required to be the same as long as the light passing through the first interferometer and the second interferometer comes from the same laser source.
The phase change value of the first to-be-detected light caused by the first interferometer is a first phase change value
Figure BDA00024567423700000419
Satisfy the requirement of
Figure BDA0002456742370000046
Wherein
Figure BDA0002456742370000047
The value of the phase change caused by the first interferometer due to the frequency of the first light to be measured,
Figure BDA0002456742370000048
is the value of the temperature induced phase change of the light caused by the first interferometer.
Similarly, the phase change value of the second light to be measured caused by the second interferometer is the first phase change value
Figure BDA0002456742370000049
Satisfy the requirement of
Figure BDA00024567423700000410
Wherein
Figure BDA00024567423700000411
The value of the optical phase change caused by the second interferometer for the frequency of the second light to be measured,
Figure BDA00024567423700000412
is the value of the temperature-induced phase change of the light caused by the second interferometer.
According to the aforementioned formula (1), the refractive index n of the waveguide material in the first interferometer is due to1Refractive index n of waveguide material in second interferometer2In the same way, the following results are obtained:
Figure BDA00024567423700000413
Figure BDA00024567423700000414
from the temperature coefficient K1To characterize the shape of the sample to be characterized,
Figure BDA00024567423700000415
from the temperature coefficient K2The method can be used for characterization so as to obtain,
Figure BDA00024567423700000416
then, the formula (2), (3), (4) and (5) can be used to obtain
Figure BDA00024567423700000417
Or
Figure BDA00024567423700000418
For example,
Figure BDA0002456742370000041
(n is the refractive index of the interferometer cavity, c is the speed of light in vacuum), (6)
The frequency f of the laser to be measured can be obtained according to the formula (6). And further, the frequency change value of the laser to be detected can be obtained by continuously detecting the frequency of the light to be detected.
The application discloses laser frequency detection device measures through the interferometer of the material encapsulation that introduces two kinds of different temperature coefficients, and the effectual temperature of having avoided measures the error that brings to laser frequency, and stability is high.
Fig. 3 is a schematic diagram of a laser frequency detection apparatus 300 according to an embodiment of the present application. As shown in fig. 3, the laser frequency detection apparatus 300 includes a beam splitter 301, a first interferometer 302, a second interferometer 303, and a demodulator 304. The first interferometer 302 has a first temperature coefficient of K1Is encapsulated by a material having a temperature coefficient of a second coefficient K outside the second interferometer 3032The material of (2) is encapsulated.
The refractive indices of the waveguide materials comprising the first interferometer 302 and the second interferometer 303 are the same, i.e. the cavity length Δ L of the first interferometer1Associated waveguide material and cavity length Δ L of the second interferometer2The refractive indices of the associated waveguide materials are the same.
The optical splitter 301 splits a beam emitted by the laser source to be measured into a first light to be measured and a second light to be measured, the first light to be measured enters the first interferometer 302, and the second light to be measured enters the second interferometer 303, wherein a phase change value of the first light to be measured caused by the first interferometer 302 is a first phase change value
Figure BDA0002456742370000051
The phase change value of the second light to be detected caused by the second interferometer is a second phase change value
Figure BDA0002456742370000052
The demodulator 304 is used for changing the value according to the first phase
Figure BDA0002456742370000053
And a second phase change value
Figure BDA0002456742370000054
And determining the light frequency f emitted by the laser source to be measured.
Alternatively, the laser frequency detection apparatus 300 may further include a reflection part 305, and the reflection part 305 is configured to reflect the first light to be measured that has passed through the first interferometer 302 to the demodulator 304, and to reflect the second light to be measured that has passed through the second interferometer 303 to the demodulator 304. The optical splitter 301 may be a coupler.
In one possible design, first interferometer 302 or second interferometer 303 may employ a Mach-Zehnder (Mach-Zehnder) interferometer structure, as shown in FIG. 4, that includes coupler 401, coupler 402, reference arm 403, signal arm 404, and package structure 405. After entering the coupler 401, the first light to be measured or the second light to be measured is split into two beams of light, which enter the reference arm 403 and the signal arm 404, and are coupled and output by the coupler 402. Wherein the length of the signal arm 404 is L1The length of the reference arm 403 is L2. Interferometer induced optical phase change
Figure BDA0002456742370000055
Or
Figure BDA0002456742370000056
Equal to the difference in phase change of the light on both the reference arm 403 and the signal arm 404. The cavity length of the interferometer needs to correspond to the amount of phase change measured by the interferometer, and thus in the mach-zehnder interferometer structure, the cavity length Δ L is L1-L2。
Fig. 5 shows a laser frequency detection apparatus 500 according to an embodiment of the present disclosure, where as shown in fig. 5, the laser frequency detection apparatus 500 includes a coupler 510, a first interferometer 520, a demodulator 530, and a second interferometer 540. The light to be measured is coupled and split by the coupler 510 to obtain a first light to be measured and a second light to be measured, the first light to be measured enters the first interferometer 520, and the second light to be measured enters the second interferometerAn interferometer 540. Wherein the phase change value of the first to-be-detected light caused by the first interferometer 520 is the first phase change value
Figure BDA0002456742370000057
The phase change value of the second light to be measured caused by the second interferometer 540 is a second phase change value
Figure BDA0002456742370000058
The demodulator 530 is used for changing the value according to the first phase
Figure BDA0002456742370000059
And a second phase change value
Figure BDA00024567423700000510
And determining the frequency f of the light to be measured.
By way of example, given one possible Sagnac interferometer configuration for first interferometer 520, first interferometer 520 includes a coupler 521 and a fiber ring 522.
In one possible design, first interferometer 520 or second interferometer 540 may also employ a Michelson interferometer structure. As shown in fig. 6, first interferometer 520 includes coupler 621 and reflective end face 622. Reflective end 622 is used to reflect optical signals incident on first interferometer 520 to demodulator 530.
It is noted that first interferometer 520 may employ a Sagnac (Sagnac) interferometer structure or the like, and second interferometer 540 may employ a Michelson (Michelson) interferometer structure or the like, i.e., the types of interferometers used by first interferometer 520 and second interferometer 540 may be different, as long as the refractive indices of the waveguide materials comprising first interferometer 520 and second interferometer 540 are the same.
In one possible design, as shown in fig. 6, demodulator 530 includes an acquisition module 641, an acquisition module 642, and a processing module 643. The collecting module 641 receives the first to-be-detected light output by the first interferometer 520 and obtains a first phase change value
Figure BDA00024567423700000511
The collecting module 642 receives the second light to be detected output by the second interferometer 540 and obtains a second phase change value
Figure BDA00024567423700000512
The processing module 643 varies the value according to the first phase
Figure BDA00024567423700000513
And a second phase change value
Figure BDA00024567423700000514
And determining the frequency f of the light to be measured.
Fig. 7 shows another laser frequency detection apparatus 700 disclosed in the embodiment of the present application. As shown in fig. 7, the laser frequency detecting apparatus 700 includes a coupler 710, a modulator 720, a circulator 730, a first interferometer 740, a second interferometer 750, a coupler 760, and a demodulator 760.
Light to be measured enters from coupler 710 and a first portion of the light to be measured is coupled out of coupler 710 into modulator 720. Modulator 720 pulses the first portion of light to be measured and outputs the first portion of light to port 1 of circulator 730. The first portion of light to be detected passes through the first interferometer 740 and the second interferometer 750 in sequence from the 2 nd port of the circulator 730, and then is output from the 3 rd port of the circulator to the coupler 760. The first portion of light to be detected is coupled out of coupler 710 and the second portion of light to be detected is coupled out of coupler 760 to demodulator 770.
The first part of light to be measured and the second part of light to be measured output from the 3 rd port of the circulator have different light frequencies, and a coherent heterodyne processing mode can be adopted to realize the acquisition of the phase of the received light signal and acquire the first phase change value of the light to be measured caused by the first interferometer 740
Figure BDA0002456742370000061
And a second phase change value of the light to be measured caused by the second interferometer 750
Figure BDA0002456742370000062
Demodulator 770 according to the first phase variation value
Figure BDA0002456742370000063
And a second phase change value
Figure BDA0002456742370000064
And determining the original light frequency f to be measured.
Alternatively, the first interferometer 740 or the second interferometer 750 may employ a fabry-perot (FP) interferometer structure, and may also employ a Mach-Zehnder (Mach-Zehnder) interferometer, a Michelson (Michelson) interferometer, a Sagnac (Sagnac) interferometer, or the like.
Alternatively, the modulator 720 is an acousto-optic modulator or an electro-optic modulator, and may be replaced by a combination of a Semiconductor Optical Amplifier (SOA) and a phase modulator.
Fig. 8 is a laser frequency detection system disclosed in an embodiment of the present application, where the system includes a laser 801, an optical splitter 802, a service end device 803, and a laser frequency detection apparatus 804. The laser 801 emits laser light, a part of the laser light is split by the optical splitter 802 and enters the laser frequency detection device 804 as laser light to be detected, and the optical splitter 802 outputs the rest of the laser light to the service end device 803 as a service signal. The laser frequency detection device 804 may be any one of the laser frequency detection devices in the above embodiments. The laser frequency detection device 804 is used for detecting the frequency of the laser output by the laser 801 to ensure the stability of the system.
The terms "first," "second," and the like in this application are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order, it being understood that the data so used may be interchanged under appropriate circumstances such that the embodiments described herein may be implemented in a sequence not described in this application.
It should also be noted that, unless otherwise specified, a specific description of some features in one embodiment may also be applied to explain that other embodiments refer to corresponding features.
The same and similar parts among the various embodiments in the present application can be referred to each other, and especially, for the embodiment of fig. 8, the description is relatively simple because of the embodiment corresponding to fig. 2 to fig. 7, and relevant parts can be referred to the part of the embodiment corresponding to fig. 2 to fig. 7 for description.
Finally, it should be noted that: the above description is only for the specific embodiments of the present application, and the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of the changes or substitutions within the technical scope of the present application, and shall be covered by the protection scope of the present application.

Claims (15)

1. A laser frequency detection device, comprising: at least two interferometers and a demodulator, the at least two interferometers including a first interferometer and a second interferometer, the first interferometer being encapsulated with a material having a temperature coefficient of a first coefficient and the second interferometer being encapsulated with a material having a temperature coefficient of a second coefficient;
the at least two interferometers are used for changing the phase of light emitted by a laser source to be measured, the phase change value of first light to be measured caused by the first interferometer is a first phase change value, the phase change value of second light to be measured caused by the second interferometer is a second phase change value, the first light to be measured is one beam of light emitted by the laser source to be measured, and the second light to be measured is the other beam of light emitted by the laser source to be measured or light output from the first interferometer;
the demodulator is used for determining the frequency of the light emitted by the laser source to be tested according to the first coefficient, the second coefficient, the first phase change value and the second phase change value.
2. The laser frequency detection device according to claim 1, wherein the laser frequency detection device further comprises a first beam splitter;
the first light splitter is used for splitting a beam of light emitted by the laser source to be measured to obtain the first light to be measured and the second light to be measured;
the first interferometer is used for changing the phase of the first to-be-detected light;
the second interferometer is used for changing the phase of the second light to be measured.
3. The laser frequency detection device according to claim 1, wherein the laser frequency detection device further comprises a circulator and a modulator;
the modulator is used for performing pulse modulation on a beam of light emitted by the laser source to be detected and shifting frequency to obtain first light to be detected;
the circulator is used for receiving the first to-be-detected light and outputting the first to-be-detected light to the first interferometer;
the first interferometer is used for changing the phase of the first light to be detected to obtain second light to be detected;
the second interferometer is used for receiving the second light to be measured and changing the phase of the second light to be measured to obtain third light to be measured;
and the circulator is also used for receiving the third light to be detected and outputting the third light to the demodulator.
4. The laser frequency detection apparatus according to claims 1 to 3, wherein the first phase change value includes a first sub-phase change value caused by a frequency of the first to-be-detected light in the first interferometer and a second sub-phase change value caused by an ambient temperature in which the first interferometer is located, the second sub-phase change value being related to the first coefficient;
the second phase change value includes a third sub-phase change value caused by the frequency of the second light to be measured in the second interferometer and a fourth sub-phase change value caused by the ambient temperature in which the second interferometer is located, and the fourth sub-phase change value is related to the second coefficient.
5. The laser frequency detection apparatus according to claim 4, wherein the demodulator is configured to determine the frequency of the light emitted by the laser source to be detected according to the first coefficient, the second coefficient, the first sub-phase variation value, the second sub-phase variation value, the third sub-phase variation value, the fourth sub-phase variation value, the first phase variation value, the second phase variation value, and the cavity length of the first interferometer and the cavity length of the second interferometer, and the cavity length is a difference between lengths of two waveguides in the interferometer for transmitting the optical signal.
6. The laser frequency detecting device according to claim 2, 4 or 5, further comprising a reflecting member for reflecting the first light-to-be-detected passing through the first interferometer and the second light-to-be-detected passing through the second interferometer to the demodulator.
7. The laser frequency detection device according to any one of claims 1 to 6, wherein the first interferometer or the second interferometer is any one of the following interferometers: fabry-perot (FP) interferometer, Mach-Zehnder (Mach-Zehnder) interferometer, Michelson (Michelson) interferometer, or Sagnac (Sagnac) interferometer.
8. The laser frequency detection device according to any of claim 3, wherein said modulator is an acousto-optic modulator or an electro-optic modulator.
9. A laser frequency detection method, comprising:
splitting the light to be measured to obtain a first light to be measured and a second light to be measured;
a first interferometer receives the first to-be-detected light, the first interferometer is packaged by a material with a temperature coefficient being a first coefficient, and a phase change value of the first to-be-detected light caused by the first interferometer is a first phase change value;
a second interferometer receives the second light to be detected, the second interferometer is packaged by a material with a second coefficient of temperature, and a phase change value of the second light to be detected caused by the second interferometer is a second phase change value;
and determining the frequency of the light to be measured according to the first coefficient, the second coefficient, the first phase change value and the second phase change value.
10. The method of claim 9, wherein the first phase change value comprises a first sub-phase change value caused by a frequency of the first light to be detected in the first interferometer and a second sub-phase change value caused by an ambient temperature at which the first interferometer is located, the second sub-phase change value being related to the first coefficient;
the second phase change value includes a third sub-phase change value caused by the frequency of the second light to be measured in the second interferometer and a fourth sub-phase change value caused by the ambient temperature in which the second interferometer is located, and the fourth sub-phase change value is related to the second coefficient.
11. The laser frequency detection apparatus according to claim 10, wherein the frequency of the light to be detected is determined based on the first coefficient, the second coefficient, the first sub phase change value, the second sub phase change value, the third sub phase change value, the fourth sub phase change value, the first phase change value, and the second phase change value.
12. A laser frequency detection method, comprising:
modulating the light to be measured to obtain first light to be measured;
a first interferometer changes the phase of the first light to be detected and obtains a second light to be detected, the first interferometer is packaged by a material with a temperature coefficient being a first coefficient, and the phase change value of the first light to be detected caused by the first interferometer is a first phase change value;
a second interferometer receives the second light to be detected, the second interferometer is packaged by a material with a second coefficient of temperature, and a phase change value of the second light to be detected caused by the second interferometer is a second phase change value;
and determining the frequency of the light to be measured according to the first coefficient, the second coefficient, the first phase change value and the second phase change value.
13. The method of claim 12, wherein the first phase change value comprises a first sub-phase change value caused by a frequency of the first light to be detected in the first interferometer and a second sub-phase change value caused by an ambient temperature at which the first interferometer is located, the second sub-phase change value being related to the first coefficient;
the second phase change value includes a third sub-phase change value caused by the frequency of the second light to be measured in the second interferometer and a fourth sub-phase change value caused by the ambient temperature in which the second interferometer is located, and the fourth sub-phase change value is related to the second coefficient.
14. The laser frequency detection apparatus according to claim 13, wherein the frequency of the light to be detected is determined based on the first coefficient, the second coefficient, the first sub phase change value, the second sub phase change value, the third sub phase change value, the fourth sub phase change value, the first phase change value, and the second phase change value.
15. A laser frequency detection system, characterized in that the system comprises a laser, a second beam splitter and a laser frequency detection device according to any one of claims 1 to 6;
the laser is used for emitting laser;
the second optical splitter is used for coupling out a part of the laser as a service signal, coupling out the other part of the laser as to-be-detected light, and outputting the to-be-detected light to the laser frequency detection device.
CN202010308589.7A 2020-04-18 2020-04-18 Laser frequency detection device and method Pending CN113541781A (en)

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