WO2018103765A1 - 一种基于光学反馈产生的重复频率可调光频梳 - Google Patents

一种基于光学反馈产生的重复频率可调光频梳 Download PDF

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WO2018103765A1
WO2018103765A1 PCT/CN2018/070001 CN2018070001W WO2018103765A1 WO 2018103765 A1 WO2018103765 A1 WO 2018103765A1 CN 2018070001 W CN2018070001 W CN 2018070001W WO 2018103765 A1 WO2018103765 A1 WO 2018103765A1
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frequency
laser
optical
output
fiber coupler
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PCT/CN2018/070001
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French (fr)
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徐善辉
赵齐来
杨中民
冯洲明
杨昌盛
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华南理工大学
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Priority to US16/315,114 priority Critical patent/US10901247B2/en
Publication of WO2018103765A1 publication Critical patent/WO2018103765A1/zh

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    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/11—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on acousto-optical elements, e.g. using variable diffraction by sound or like mechanical waves
    • G02F1/113—Circuit or control arrangements
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    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/09—Processes or apparatus for excitation, e.g. pumping
    • H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
    • H01S3/0912—Electronics or drivers for the pump source, i.e. details of drivers or circuitry specific for laser pumping
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    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/06—Construction or shape of active medium
    • H01S3/063—Waveguide lasers, i.e. whereby the dimensions of the waveguide are of the order of the light wavelength
    • H01S3/067—Fibre lasers
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    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/06—Construction or shape of active medium
    • H01S3/063—Waveguide lasers, i.e. whereby the dimensions of the waveguide are of the order of the light wavelength
    • H01S3/067—Fibre lasers
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    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/09—Processes or apparatus for excitation, e.g. pumping
    • H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
    • H01S3/0915—Processes or apparatus for excitation, e.g. pumping using optical pumping by incoherent light
    • H01S3/0933—Processes or apparatus for excitation, e.g. pumping using optical pumping by incoherent light of a semiconductor, e.g. light emitting diode
    • H—ELECTRICITY
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    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/09—Processes or apparatus for excitation, e.g. pumping
    • H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
    • H01S3/094—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light
    • H01S3/094003—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light the pumped medium being a fibre
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    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/09—Processes or apparatus for excitation, e.g. pumping
    • H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
    • H01S3/094—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light
    • H01S3/094065—Single-mode pumping
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    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
    • H01S3/10038—Amplitude control
    • H01S3/10046—Pulse repetition rate control
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    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
    • H01S3/10084—Frequency control by seeding
    • H01S3/10092—Coherent seed, e.g. injection locking
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    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
    • H01S3/106—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling devices placed within the cavity
    • H01S3/1068—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling devices placed within the cavity using an acousto-optical device
    • H—ELECTRICITY
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    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
    • H01S3/11—Mode locking; Q-switching; Other giant-pulse techniques, e.g. cavity dumping
    • H01S3/1106—Mode locking
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F2201/00—Constructional arrangements not provided for in groups G02F1/00 - G02F7/00
    • G02F2201/02—Constructional arrangements not provided for in groups G02F1/00 - G02F7/00 fibre
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F2201/00—Constructional arrangements not provided for in groups G02F1/00 - G02F7/00
    • G02F2201/58—Arrangements comprising a monitoring photodetector
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F2203/00—Function characteristic
    • G02F2203/25—Frequency chirping of an optical modulator; Arrangements or methods for the pre-set or tuning thereof
    • H—ELECTRICITY
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    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/06—Construction or shape of active medium
    • H01S3/063—Waveguide lasers, i.e. whereby the dimensions of the waveguide are of the order of the light wavelength
    • H01S3/067—Fibre lasers
    • H01S3/0675—Resonators including a grating structure, e.g. distributed Bragg reflectors [DBR] or distributed feedback [DFB] fibre lasers
    • H—ELECTRICITY
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    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/08—Construction or shape of optical resonators or components thereof
    • H01S3/081—Construction or shape of optical resonators or components thereof comprising three or more reflectors
    • H01S3/082—Construction or shape of optical resonators or components thereof comprising three or more reflectors defining a plurality of resonators, e.g. for mode selection or suppression
    • H—ELECTRICITY
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    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
    • H01S3/11—Mode locking; Q-switching; Other giant-pulse techniques, e.g. cavity dumping
    • H01S3/1106—Mode locking
    • H01S3/1109—Active mode locking

Definitions

  • the present invention relates to optical frequency combs, and more particularly to a repeatable frequency tunable optical frequency comb based on optical feedback.
  • Optical frequency comb is a kind of light source with comb frequency spectrum, which is important in high precision frequency scale, precision ranging, microwave photonics arbitrary wave generator, microwave photonic signal processing, dense wavelength division multiplexing and other related fields.
  • Applications, optical clocks based on optical frequency combs can increase the accuracy of atomic clocks by more than two orders of magnitude. In view of its important theoretical significance and application value, optical frequency comb is becoming a hot topic in related fields.
  • optical comb production schemes There are several conventional optical comb production schemes: one is to use a mode-locked laser to output a periodic pulse sequence in the time domain, and to perform a Fourier transform on a periodic pulse to obtain an optical frequency with equal frequency intervals in the frequency domain. comb.
  • the dispersion existing inside the laser causes a fixed difference between the phase accumulation of the envelope and the carrier phase accumulation, so calibration is required.
  • the advantage of the scheme is that the structure is simple, and the number of generated carriers is large, but there are disadvantages such as difficulty in controlling the number of carriers, poor flatness, and uncertain carrier spacing.
  • the second is a nonlinear fiber.
  • Such a scheme utilizes nonlinear effects in a highly nonlinear fiber such as self-phase modulation and cascaded four-wave mixing to obtain a large bandwidth optical frequency comb.
  • the number of optical frequency combs generated in this way is large, but there are disadvantages such as poor carrier flatness and uncontrollable carrier number.
  • the third is Single / Cascaded electro-optic modulator. This method is a relatively easy to implement, widely used optical frequency comb generation solution.
  • Common cascaded electro-optic modulator schemes include intensity modulator cascade phase modulators, polarization modulator cascade phase modulator phase modulator cascade phase modulators, polarization modulator cascade polarization modulators, and the like.
  • the main idea is to change the performance of the output optical frequency comb by controlling the parameters of the RF source amplitude, bias voltage, frequency and so on.
  • the scheme has the advantages of stable wavelet spacing and simple generation mode. However, if the RF drive voltage is required to obtain a larger carrier number, the flatness of the carrier is not ideal.
  • Cyclic frequency shifter-based generation schemes include single sideband cyclic frequency shifter (SSB-RFS), phase modulator combined with cyclic frequency shifter (PM-RFS), multiple cyclic frequency shifter (MC-RFS), polarization modulation
  • SSB-RFS single sideband cyclic frequency shifter
  • PM-RFS phase modulator combined with cyclic frequency shifter
  • MC-RFS multiple cyclic frequency shifter
  • polarization modulation In combination with a cyclic frequency shifter (PolM-RFS) scheme, the basic principle is to use cyclic frequency shift to increase the number of carriers generated.
  • the advantage of this method is that the number of optical frequency combs generated is large and the flatness is good, but there are disadvantages such as that the carrier phase relationship is not obvious and the carrier noise is large.
  • the optical frequency comb based on the optical feedback mechanism can effectively suppress the problem of large carrier noise, and can generate more optical frequency combs, change the delay time in the optical feedback device, and can also obtain different Repeat the frequency of the frequency comb.
  • the object of the present invention is to overcome the above deficiencies in the prior art and to provide a repeatable frequency tunable optical frequency comb based on optical feedback.
  • the laser optical feedback device is combined with the frequency locking function to generate a laser optical frequency comb with adjustable repetition frequency.
  • a repetition frequency tunable optical frequency comb based on optical feedback including Single frequency laser cavity, wavelength division multiplexer, single mode semiconductor pump source, optical circulator, first fiber coupler, second fiber coupler, photodetector, high stability signal source, error signal processing system, laser Frequency modulation device, adjustable laser delay module;
  • the structural relationship of each component is: the single-frequency laser cavity is connected with the common end of the wavelength division multiplexer, the pumping end of the wavelength division multiplexer is connected with the single-mode semiconductor pumping light source, and the signal terminal of the wavelength division multiplexer a 2-port connection of the optical circulator, the input end of the first fiber coupler is connected to the 3-port of the optical circulator, and an output end of the first fiber coupler is connected to the input end of the second fiber coupler,
  • the input end of the laser frequency modulation device is connected to the other output end of the first fiber coupler
  • the adjustable laser delay module is respectively connected to the output of the laser frequency modulation device and One port of the optical circulator, one output of the
  • the repetition frequency is in the range of less than 10 MHz.
  • the output of the single-frequency laser cavity is a single-frequency laser with continuous single-frequency, frequency-modulated output at any wavelength.
  • the high stability signal source includes, but is not limited to, a crystal oscillator, a signal generator, an atomic clock, and the like.
  • the laser frequency modulating device includes, but is not limited to, a fiber stretcher, an acousto-optic modulator, an electro-optic modulator, and the like.
  • the tunable laser delay module includes, but is not limited to, a fiber delay line, a high reflectivity laser cavity, and the like.
  • the output laser of the single-frequency laser cavity passes through the tunable laser delay module, and optical feedback is injected through the optical circulator to In a single-frequency laser cavity, a series of laser longitudinal modes with equal frequency intervals are produced.
  • a high-stability signal source, an error signal processing system and a laser frequency modulation device are combined to realize laser frequency locking, and a laser optical frequency comb is generated.
  • the present invention has the following advantages and technical effects:
  • the pump light output from the single-mode semiconductor pumping source is pumped to the single-frequency fiber laser cavity by the wavelength division multiplexer, and the laser signal output from the fiber resonator through the wavelength division multiplexer passes through the optical circulator and enters the A fiber coupler achieves laser splitting.
  • a part of the light is re-injected into the single-frequency fiber laser cavity through the laser frequency modulation device and the adjustable laser delay module into the optical circulator to realize optical feedback.
  • the present invention combines optical feedback and frequency locking in comparison to conventional lock mode lasers or optical microcavities to produce optical frequency combs, providing an efficient solution that is simpler and has adjustable frequency spacing.
  • FIG. 1 is a schematic diagram of a repetition frequency tunable optical frequency comb based on optical feedback according to an embodiment of the present invention.
  • 1 - single frequency laser cavity 1 - single frequency laser cavity, 2 - wavelength division multiplexer, 3 - single mode semiconductor pump light source, 4 - optical circulator, 5 - first fiber coupler, 6 - second fiber coupler, 7 - photodetector, 8 - high stable signal source, 9 - error signal processing system, 10 - laser frequency modulation device, 11 - Adjustable laser delay module.
  • a 980 nm single-mode semiconductor laser is used as a single-mode semiconductor pumping source 3, after 980/1550 nm.
  • the polarization-maintaining wavelength division multiplexer 2 implements backward pumping of the single-frequency laser cavity 1 .
  • Single-frequency laser cavity 1 is a single-frequency fiber distributed Bragg reflection type (DBR) with an output laser wavelength of 1550.52 nm. ) Resonant cavity. After passing through the 1550 nm polarization-maintaining fiber circulator 4, the output laser enters the first fiber coupler with a split ratio of 50:50.
  • the high stable signal source 8 in this example is a highly stable frequency.
  • the 50MHz temperature-compensated crystal oscillator, the laser frequency modulation device 10 is an acousto-optic modulator, and the adjustable laser delay module 11 is a 1km long fiber delay line.
  • the part of the output is connected to two second fiber couplers 6 with a split ratio of 10:90, of which 10% of the light enters the photodetector 7, 90%
  • the port acts as an output port for the optical comb.
  • the photodetector obtains the 50MHz standard signal of the electrical signal and the temperature-compensated crystal oscillator and simultaneously inputs it into the error signal processing system.
  • the error signal processing system can adopt an existing signal processing system.
  • the error signal processing system 9 performs band-pass filtering on the electrical signal measured by the photodetector to obtain 50MHz. A comb signal is nearby, and the temperature-compensated crystal signal is band-pass filtered to eliminate harmonic signals of other frequency components. The two signals are then effectively amplified, mixed into the mixer and a low pass filter is added to obtain the low frequency error signal. This low frequency error signal carries both the frequency fluctuation information of the optical frequency comb and the amplitude fluctuation information.
  • PID Differential
  • the obtained signal is loaded into the laser frequency modulation device 10, achieve After the frequency is locked, the laser frequency comb with stable frequency is output.
  • the present invention combines optical feedback and frequency locking in comparison to conventional lock mode lasers or optical microcavities to produce optical frequency combs, providing an efficient solution that is simpler and has adjustable frequency spacing.

Abstract

一种基于光学反馈产生的重复频率可调光频梳，其包括单频激光谐振腔(1)、波分复用器(2)、单模半导体泵浦光源(3)、光环行器(4)、第一光纤耦合器(5)、第二光纤耦合器(6)、光电探测器(7)、高稳定信号源(8)、误差信号处理系统(9)、激光频率调制装置(10)和可调激光延迟模块(11)；利用可调激光延迟模块(11)对单频激光进行延时处理，并通过光环形器(4)实现光学反馈注入到谐振腔中(1)，产生一系列频率间隔相等并且可调的激光纵模，同时结合高稳定信号源(8)、误差信号处理系统(9)和激光频率调制装置(10)实现激光频率锁定，产生激光光频梳。

Description

一种基于光学反馈产生的重复频率可调光频梳
技术领域
本发明涉及光频梳，特别是涉及一种 基于光学反馈产生的重复频率可调光频梳 。
背景技术
光频梳是一种具有梳状频率谱的光源，其在高精度频标、精密测距、微波光子学任意波发生器、微波光子学信号处理、密集波分复用等相关领域有重要的应用，基于光频梳的光钟可以将原子钟的精度提高两个量级以上。鉴于其重要理论意义和应用价值，光频梳正成为相关领域研究的热点。
传统的光频梳产生方案有一下几种：一是利用锁模激光器在时域上的输出为周期性脉冲序列,针对周期性脉冲作傅里叶变换得到在频域上频率间隔相等的光学频率梳。但是激光器内部存在的色散会使包络的相位积累和载波相位积累存在固定的差值,因此需要进行校准。该方案的优点是结构简单,产生的载波数目较多,但是存在载波数目不易控制、平坦度差、载波间隔不确定等缺点。二是非线性光纤。此种方案是利用高非线性光纤中的非线性效应如自相位调制、级联四波混频来得到大带宽的光频梳。这种方式产生的光频梳数目较多,但是存在载波平坦度不好、载波数目不可控等缺点。三是 单个 / 级联的电光调制器。此方法是相对较容易实现、应用也较为广泛的光频梳产生方案。常见的级联的电光调制器方案包括强度调制器级联相位调制器、偏振调制器级联相位调制器相位调制器级联相位调制器、偏振调制器级联偏振调制器等方案。主要思想是通过控制射频源幅度、偏置电压、频率等参数来整改变输出光频梳的性能。该方案具有子波间隔稳定、产生方式较为简单等优点 , 但是若想获得较大的载波数目需要的射频驱动电压较高 , 载波的平坦度也不够理想。
另外基于循环频移器RFS结构(Recirculating frequency shifter)也可以产生光频梳。基于循环频移器的产生方案包括单边带循环频移器(SSB-RFS)、相位调制器结合循环频移器(PM-RFS)、多路循环频移器(MC-RFS)、偏振调制器结合循环频移器(PolM-RFS)等方案,其基本原理是利用循环频移来增大产生的载波数目。这种方式的优点是产生的光频梳数目较多、平坦度较好,但是存在载波相位关系不明显、载波噪声较大等缺点。
而基于光学反馈机制产生光频梳可以有效抑制载波噪声较大的问题，同时可以产生较多的光频梳数目，改变光学反馈装置中的延迟时间，还可以获得不同 重复频率的光频梳。
发明内容
本发明的目的在于克服现有技术上述中的不足，提供一种 基于光学反馈产生的重复频率可调光频梳 。通过激光光学反馈装置结合频率锁定作用，从而产生重复频率可调的激光光频梳。
本发明的目的通过如下技术方案实现。
一种 基于光学反馈产生的重复频率可调光频梳 ， 包括 单频激光谐振腔、波分复用器、单模半导体泵浦光源、光环行器、第一光纤耦合器、第二光纤耦合器、光电探测器、高稳定信号源、误差信号处理系统、激光频率调制装置、可调激光延迟模块； 各部件的结构关系是：单频激光谐振腔与波分复用器的公共端连接，波分复用器的泵浦端与单模半导体泵浦光源连接，波分复用器的信号端与光环行器的2端口连接，第一光纤耦合器的输入端和光环形器的3端口连接，第一光纤耦合器的一个输出端连接第二光纤耦合器的输入端， 激光频率调制装置的输入端连接 第一光纤耦合器的另一个输出端， 可调激光延迟模块分别连接激光频率调制装置的输出端和 光环行器的1端口，第二光纤耦合器的一个输出端作为光频梳的输出， 光电探测器的输入端连接 第二光纤耦合器的另一个输出端， 高稳定信号源和光电探测器的输出端同时连接误差信号处理系统，误差信号处理系统的输出端连接激光频率调制装置的控制端。
进一步地，所述的重复频率在小于10MHz范围内。
进一步地，所述的单频激光谐振腔的输出为连续单频、频率调制的任意波长输出的单频激光。
进一步地，所述的 高稳定信号源 包括但不限于晶振、信号发生器、原子钟等。
进一步地，所述的 激光频率调制装置 包括但不限于光纤拉伸器、声光调制器、电光调制器等。
进一步地，所述的 可调激光延迟模块 包括但不限于光纤延迟线、高反射率激光腔体等。
进一步地，所述的单频激光谐振腔的输出激光经过 可调激光延迟模块 后， 并通过光环形器实现光学反馈注入到 单频激光谐振腔 中，产生一系列频率间隔相等的激光纵模。同时结合高稳定信号源、误差信号处理系统和激光频率调制装置实现激光频率锁定，产生激光光频梳。
与现有技术相比，本发明具有如下优点和技术效果：
单模半导体泵浦光源输出的泵浦光经波分复用器对单频光纤激光谐振腔进行泵浦，从光纤谐振腔经波分复用器输出的激光信号经过光环行器后，进入第一光纤耦合器实现激光分束。其中一部分光经过激光频率调制装置、可调激光延迟模块进入光环行器重新注入单频光纤激光谐振腔中，实现光学反馈。而另一部分光进入另一个第二光纤耦合器，从第二光纤耦合器输出的一部分光进入光电探测器转化为电信号，该电信号携带了激光的幅度和频率波动信息，误差信号处理系统将改电信号与高稳定信号源的信号进行运算处理后，加载到激光频率调制装置上，实现激光频率锁定，产生激光光频梳。与传统的基于锁模激光器或者光学微腔产生光频梳的方案相比，本发明将光学反馈和频率锁定相结合，提供了一种在更为简易而且频率间隔可调的有效方案。
附图说明
图1为本发明实施例一种基于光学反馈产生的重复频率可调光频梳原理示意图。
图中： 1 -单频激光谐振腔、 2 -波分复用器、 3 -单模半导体泵浦光源、 4 -光环行器、 5 -第一光纤耦合器、 6 -第二光纤耦合器、 7 -光电探测器、 8 -高稳定信号源、 9 -误差信号处理系统、 10 -激光频率调制装置、 11 -可调激光延迟模块。
具体实施方式
下面结合附图和具体例子对本发明的具体实施方式作进一步描述，需要说明的是本发明要求保护的范围并不局限于实施例表述的范围，同时以下若有未特别详细说明的部分，均是本领域技术人员可参照现有技术实现的。
实施例 1
本例中利用 980nm 单模半导体激光器作为单模半导体泵浦光源 3 ，经过 980/1550nm 的保偏波分复用器 2 实现对单频激光谐振腔 1 进行后向泵浦。单频激光谐振腔 1 为输出激光波长为 1550.52nm 的单频光纤分布布拉格反射式（ DBR ）谐振腔。输出激光经过 1550nm 保偏光纤环形器 4 后，进入分光比为 50:50 的第一光纤耦合器 5 。此例中的高稳定信号源 8 为一个高稳定的频率为 50MHz 的温补晶振，激光频率调制装置 10 为声光调制器，可调激光延迟模块 11 为 1km 长的光纤延迟线。从 第一光纤耦合器 5 中输出的部分光接两一个分光比为 10:90 的第二光纤耦合器 6 ，其中 10% 的光进入光电探测器 7 ， 90% 的端口作为光频梳的输出端口。光电探测器获得电信号和温补晶振的 50MHz 的标准信号同时输入到误差信号处理系统 9 中，误差信号处理系统可以采用现有的信号处理系统。误差信号处理系统 9 会对光电探测器测得电信号进行带通滤波获得 50MHz 附近的一个梳齿信号，同时对温补晶振信号进行带通滤波以消除其他频率成分的谐波信号。然后对两个信号进行有效放大，进入混频器混频并加上一个低通滤波器获得低频频率误差信号。这个低频误差信号既携带着光频梳的频率波动信息，也携带着幅度波动信息。通过对该误差信号进行比例 - 积分 - 微分（ Proportion Integration Differentiation ， PID ）运算处理后，得到的信号加载到激光频率调制装置 10 ，实现 频率锁定后，输出频率稳定的激光光频梳。与传统的基于锁模激光器或者光学微腔产生光频梳的方案相比，本发明将光学反馈和频率锁定相结合，提供了一种在更为简易而且频率间隔可调的有效方案。

Claims (7)

  1. 一种基于光学反馈产生的重复频率可调光频梳，其特征在于包括 单频激光谐振腔（ 1 ）、波分复用器（ 2 ）、单模半导体泵浦光源（ 3 ）、光环行器（ 4 ）、第一光纤耦合器（ 5 ）、第二光纤耦合器（ 6 ）、光电探测器（ 7 ）、高稳定信号源（ 8 ）、误差信号处理系统（ 9 ）、激光频率调制装置（ 10 ）、可调激光延迟模块（ 11 ） ； 各部件的结构关系是：单频激光谐振腔（1）与波分复用器（2）的公共端连接，波分复用器（2）的泵浦端与单模半导体泵浦光源（3）连接，波分复用器（2）的信号端与光环行器（4）的2端口连接，第一光纤耦合器（5）的输入端和光环形器（4）的3端口连接，第一光纤耦合器（5）的一个输出端连接第二光纤耦合器（6）的输入端， 激光频率调制装置（ 10 ）的输入端连接 第一光纤耦合器（5）的另一个输出端， 可调激光延迟模块（ 11 ）分别连接激光频率调制装置（ 10 ）的输出端和 光环行器（4）的1端口，第二光纤耦合器（6）的一个输出端作为光频梳的输出， 光电探测器（ 7 ）的输入端连接 第二光纤耦合器（6）的另一个输出端， 高稳定信号源（ 8 ）和光电探测器（ 7 ）的输出端同时连接误差信号处理系统（ 9 ），误差信号处理系统（ 9 ）的输出端连接激光频率调制装置（ 10 ）的控制端。
  2. 根据权利要求1所述的一种基于光学反馈产生的重复频率可调光频梳，其特征在于：所述的重复频率小于10MHz。
  3. 根据权利要求1所述的一种基于光学反馈产生的重复频率可调光频梳，其特征在于：所述的单频激光谐振腔（1）的输出为连续单频、频率调制的任意波长输出的单频激光。
  4. 根据权利要求1所述的一种基于光学反馈产生的重复频率可调光频梳，其特征在于：所述的 高稳定信号源 （8）包括晶振、信号发生器或原子钟。
  5. 根据权利要求1所述的一种基于光学反馈产生的重复频率可调光频梳，其特征在于：所述的 激光频率调制装置（ 10 ） 包括光纤拉伸器、声光调制器、电光调制器或磁光调制器。
  6. 根据权利要求1所述的一种基于光学反馈产生的重复频率可调光频梳，其特征在于：所述的 可调激光延迟模块（ 11 ） 包括光纤延迟线或高反射率激光腔体。
  7. 根据权利要求1所述的一种基于光学反馈产生的重复频率可调光频梳，其特征在于：所述的单频激光谐振腔（1）的输出激光经过 可调激光延迟模块（ 11 ）
    后， 并通过光环形器（ 4 ）实现光学反馈注入到 单频激光谐振腔（1） 中，产生频率间隔相等的激光纵模；同时结合高稳定信号源 （8） 、误差信号处理系统（ 9 ）和激光频率调制装置（ 10 ）实现激光频率锁定，产生激光光频梳。
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