High-stability microcavity optical comb generation device and method

Abstract

The invention discloses a high-stability microcavity optical comb generation device and method. The device comprises a pump laser, a light source locking module, a repetition frequency locking module, an optical comb optical system and a microcavity control system. The pump laser provides pump laser of the microcavity optical comb, one path is connected to the light source locking module, the other path is connected to the repetition frequency locking module, the light source locking module locks the pump frequency of the pump laser, and the repetition frequency locking module locks the repetition frequency of the microcavity optical comb; the optical comb optical system shunts the laser, one path is connected to the microcavity control system, and the other path is connected to the acousto-optic modulator; the acousto-optic modulator performs frequency shift on the laser to generate first-order diffracted light, and the output of the acousto-optic modulator is connected to the micro-cavity control system; the micro-cavity control system comprises a micro-cavity chip and a temperature control unit, and the temperature control unit is used for controlling the micro-cavity chip to generate a micro-cavity optical comb through temperature regulation. The optical comb generating device can generate the optical comb which can reliably and stably operate for a long time and is simple in structure and easy to debug.

Description

Technical Field

[0001] This invention belongs to the field of ultrafast lasers, specifically relating to a highly stable microcavity optical comb generation device and method. Background Technology

[0002] Optical frequency comb technology has attracted much attention as a novel light source technology. In the field of photonic microwave generation, optical frequency combs, with their precise frequency characteristics, can provide a highly stable frequency reference for microwave signals, greatly improving the quality and performance of microwave signals. In wavelength division multiplexing (WDM) communication, optical frequency combs can serve as ideal multi-wavelength light sources, significantly increasing the number of channels in communication systems, effectively improving communication capacity, and meeting the ever-increasing data transmission demands of modern communication. Furthermore, in the field of high-precision measurement and sensing, optical frequency combs also demonstrate unparalleled advantages, enabling high-precision measurement and accurate sensing of various physical quantities. Although microcavity optical comb technology is constantly developing, it still faces many challenges in practical applications, especially the stability of the optical comb, which limits its further development and widespread application. Therefore, a highly stable optical comb system is of great significance for reliable use in different environments. However, existing microcavity optical comb generation systems suffer from complex structures, difficult debugging, and poor stability. Summary of the Invention

[0003] The purpose of this invention is to provide a highly stable microcavity optical comb generating device and method, which can generate an optical comb that can operate reliably and stably for a long time and has a simple structure and is easy to debug.

[0004] To achieve the above objectives, one aspect of the present invention provides a high-stability microcavity optical comb generating device, comprising a pump laser, a first fiber beam splitter, a light source locking module, a repetition rate locking module, an optical comb optical system, and a microcavity control system. The pump laser is used to provide pump laser for the microcavity optical comb. The first fiber beam splitter is used to split the laser output from the pump laser. One path is connected to the light source locking module, and the other path is connected to the repetition rate locking module. The light source locking module is used to lock the pump frequency of the pump laser, and the repetition rate locking module is used to lock the repetition rate of the microcavity optical comb. The optical comb system includes a second fiber beam splitter, first and second optical amplifiers, first and second circulators, and an acousto-optic modulator. The second fiber beam splitter is used to split the laser. Its input end is the output end of the light source locking module. One output is connected to the first optical amplifier, which is connected to the microcavity control system through the first optical amplifier and the first circulator. The other output is connected to the acousto-optic modulator. The acousto-optic modulator is used to shift the frequency of the laser to generate first-order diffracted light. The output of the acousto-optic modulator is connected to the second optical amplifier, and then connected to the microcavity control system through the second optical amplifier and the second circulator. The microcavity control system includes a microcavity chip and a temperature control unit. The temperature control unit is used to control the microcavity chip to generate a microcavity optical comb by adjusting the temperature.

[0005] Another aspect of the present invention provides a method for generating a highly stable microcavity optical comb, which utilizes the above-described apparatus to generate a highly stable microcavity soliton optical comb, comprising: The pump laser is locked using a light source locking module to generate a stable pump laser. The power values ​​of the first and second optical amplifiers were initially set to enable them to generate comb teeth; Adjust the temperature control unit to lower it from a high temperature to a low temperature until comb teeth are observed to be produced, indicating that the window for comb production has been entered. Set the first and second optical amplifiers to appropriate power values ​​and adjust the temperature until a soliton optical comb is generated. The repetition rate locking module is used to lock the repetition rate while keeping the soliton optical comb online throughout the process, thereby achieving high-stability microcavity optical comb generation within the repetition rate locking range.

[0006] According to the high-stability microcavity optical comb generating apparatus and method of the present invention described above, an optical comb that can operate reliably and stably for a long time can be generated and has a simple structure and is easy to debug. Attached Figure Description

[0007] To more clearly illustrate the technical solutions of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort: Figure 1 This is a schematic diagram of a high-stability microcavity optical comb generating device according to an embodiment of the present invention. Detailed Implementation

[0008] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0009] One embodiment of the present invention provides a highly stable microcavity optical comb generating device, such as... Figure 1 As shown, the high-stability microcavity optical comb generating device of this invention includes a pump laser 1, a first fiber beam splitter 2, a light source locking module 3, a repetition rate locking module 4, an optical comb optical system, and a microcavity control system.

[0010] Pump laser 1 is used as a light source to provide pump laser for the microcavity optical comb. The type of laser is not limited and can be a narrow linewidth laser, a DFB laser, or a tunable laser, etc. The first fiber beam splitter 2 is used to split the pump laser output from pump laser 1, one path of which is connected to the light source locking module 3, and the other path is connected to the repetition rate locking module 4.

[0011] The light source locking module 3 is used to lock the pump frequency. Depending on the requirements for the stability of the microcavity optical comb, a locking system based on saturated absorption spectrum, modulation transfer spectrum or PDH can be selected. The pump frequency of the pump laser is determined according to the different locking systems, typically 1550nm, 1556nm or 1560nm.

[0012] The repetition frequency locking module 4 is used to lock the repetition frequency of the microcavity optical comb. Utilizing the principle of injection locking, the RF source used in this module is locked to clocks with different stability requirements.

[0013] The optical comb system includes a second fiber beam splitter 5, a first optical amplifier 7, a second optical amplifier 9, a first circulator 8, a second circulator 10, and an acousto-optic modulator 6. These optical components in the optical comb system can be either single-mode fiber devices or polarization-maintaining fiber devices. If single-mode fiber devices are selected, a polarization controller is added after the optical comb system and before the microcavity control system. If polarization-maintaining fiber devices are selected, this controller is not required and offers higher stability.

[0014] The second fiber beam splitter 5 is used to split the laser beam. Its input is the output of the repetition rate locking module 4. One output is used as the pump laser and directly connected to the first optical amplifier 7. The first optical amplifier 7 and the first circulator 8 then connect to the microcavity control system. The other output connects to the acousto-optic modulator 6. The first optical amplifier 7 and the second optical amplifier 9 are used to amplify the laser power; both beams after splitting need to be amplified. The acousto-optic modulator 6 is used to frequency-shift the laser beam to produce first-order diffracted light. Its bandwidth is determined by the full width at half maximum (FWHM) of the transmission spectrum of the microcavity optical comb (the quality factor of the microcavity). The higher the quality factor, the wider the transmission spectrum broadens, and the greater the corresponding frequency shift; that is, the higher the quality factor, the greater the bandwidth of the acousto-optic modulator. The first circulator 8 and the second circulator 10 are used to control the propagation direction of the two beams.

[0015] The output of the acousto-optic modulator 6 is connected to the second optical amplifier 9, and then to the microcavity control system via the second optical amplifier 9 and the second circulator 10. The microcavity control system is used to control the generation of the microcavity optical comb. The microcavity control system includes a microcavity chip 11 and a temperature control unit 12. The temperature control unit 12 is used to control the generation of the microcavity optical comb by adjusting the temperature of the microcavity chip 12.

[0016] In summary, the high-stability microcavity optical comb generation device of this invention comprises a source locking module (center frequency locking), a repetition rate locking module, an optical comb optical system, and a microcavity control system, which are decoupled from each other. This device, through a locking loop design tailored to a specific optical comb generation optical system, eliminates the need for frequency sweeping to generate the optical comb, thus minimizing the requirements for the laser; any type of laser can be used as the pump source for the optical comb. Furthermore, the microcavity control system is simply composed of a microcavity chip and a temperature control unit, compatible with various microcavity optical combs, and represents a highly integrated, easily adjustable, and perturbation-free microcavity optical comb stabilization solution.

[0017] Embodiments of the present invention also provide a method for generating a high-stability microcavity optical comb. The method utilizes the high-stability microcavity optical comb generating device described above to generate a highly stable microcavity soliton optical comb that operates stably for extended periods. The generation sequence generally consists of three steps: first, pump laser locking; second, generating the optical comb using the locked pump laser; and finally, frequency repetition locking. First, the pump laser 1 is locked using the light source locking module 3 to generate a stable pump laser; The power values ​​of the two optical amplifiers 7 and 9 were initially set so that they could produce comb teeth; Adjust the temperature control unit 12 of the microcavity to reduce it from high temperature to low temperature until comb teeth are observed to be produced, indicating that the window for optical comb production has been entered. Set the two optical amplifiers 7 and 9 to appropriate power values ​​and adjust the temperature until a soliton optical comb is generated. The repetition rate locking module is used to lock the repetition rate while maintaining the soliton optical comb in online operation. Within the repetition rate locking range, the microcavity optical comb has extremely high stability, thus realizing the generation of a highly stable microcavity optical comb.

[0018] The generation and online monitoring of soliton optical combs can be performed using a spectrometer.

[0019] The high-stability microcavity optical comb generating device and method of the present invention have the following beneficial effects; This invention achieves a fully locked microcavity optical frequency comb, enabling the generated optical comb to operate reliably and stably for extended periods. The various subsystems of the device are decoupled from each other, making the entire locking process simple, easy to operate, and independent. The device structure and debugging methods are highly compatible, adaptable to various laser sources, various light source locking devices and methods, various microcavity structures, and microcavity optical combs with various parameters. Compared to traditional microcavity optical comb generation systems, it features a simpler device and a more straightforward debugging method, strong repeatability, and overall higher stability.

[0020] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A high-stability microcavity optical comb generating device, characterized in that, It includes a pump laser, a first fiber beam splitter, a light source locking module, a repetition rate locking module, an optical comb system, and a microcavity control system; The pump laser is used to provide pump laser for the microcavity optical comb. The first fiber beam splitter is used to split the laser output from the pump laser. One path is connected to the light source locking module, and the other path is connected to the repetition rate locking module. The light source locking module is used to lock the pump frequency of the pump laser, and the repetition rate locking module is used to lock the repetition rate of the microcavity optical comb. The optical comb system includes a second fiber beam splitter, first and second optical amplifiers, first and second circulators, and an acousto-optic modulator. The second fiber beam splitter is used to split the laser. Its input end is the output end of the light source locking module. One output is connected to the first optical amplifier, which is connected to the microcavity control system through the first optical amplifier and the first circulator. The other output is connected to the acousto-optic modulator. The acousto-optic modulator is used to shift the frequency of the laser to generate first-order diffracted light. The output of the acousto-optic modulator is connected to the second optical amplifier, and then connected to the microcavity control system through the second optical amplifier and the second circulator. The microcavity control system includes a microcavity chip and a temperature control unit. The temperature control unit is used to control the microcavity chip to generate a microcavity optical comb by adjusting the temperature.

2. The apparatus as claimed in claim 1, characterized in that, The pump laser is a narrow linewidth laser, a DFB laser, or a tunable laser, with a pump frequency of 1550nm, 1556nm, or 1560nm.

3. The apparatus as described in claim 1 or 2, characterized in that, The light source locking module selects a locking system based on saturated absorption spectrum, modulation transfer spectrum, or PDH, and the pump frequency of the pump laser is determined according to the different locking systems.

4. The apparatus as described in claim 1 or 2, characterized in that, The frequency repetition locking module uses injection locking to lock the frequency repetition of the microcavity optical comb. According to different stability requirements, the frequency repetition locking module locks its radio frequency source to clocks with different stability.

5. The apparatus as described in claim 1 or 2, characterized in that, The optical components in the optical comb system are either single-mode fiber devices or polarization-maintaining fiber devices. If single-mode fiber devices are selected, a polarization controller is added between the optical comb system and the microcavity control system.

6. A method for generating a highly stable microcavity optical comb, characterized in that, Generating a highly stable microcavity soliton optical comb using the apparatus of any one of claims 1-5, comprising: The pump laser is locked using a light source locking module to generate a stable pump laser. The power values ​​of the first and second optical amplifiers were initially set to enable them to generate comb teeth; Adjust the temperature control unit to lower it from a high temperature to a low temperature until comb teeth are observed to be produced, indicating that the window for comb production has been entered. Set the first and second optical amplifiers to appropriate power values ​​and adjust the temperature until a soliton optical comb is generated. The repetition rate locking module is used to lock the repetition rate while keeping the soliton optical comb online throughout the process, thereby achieving high-stability microcavity optical comb generation within the repetition rate locking range.

7. The method as described in claim 6, characterized in that, The generation and online operation of soliton optical combs were monitored using a spectrometer.

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