A system and method for manipulating the time domain position of microcavity optical frequency comb soliton pulses

Abstract

The present invention relates to a modulation system and method for microcavity optical frequency comb soliton pulses, and specifically to a system and method for manipulating the time domain position of microcavity optical frequency comb soliton pulses, which is used to solve the problem that it is difficult to achieve accurate all-optical control of the time domain position of femtosecond soliton pulses in a microcavity optical frequency comb system. The system for manipulating the time domain position of microcavity optical frequency comb soliton pulses can achieve full-cycle all-optical arbitrary control of microcavity soliton pulses by only modulating the phase of a pump laser, and achieves control accuracy of the fs level or even the as level.

Description

Technical Field

[0001] The present invention relates to a modulation system and method for a microcavity optical frequency comb soliton pulse, and in particular to a system and method for manipulating the time domain position of a microcavity optical frequency comb soliton pulse. Background Art

[0002] The development of ultrafast science relies heavily on the time control and precise manipulation of optical pulses, especially high-precision control on the femtosecond (fs) time scale. Traditional optical pulse control technology is mostly based on mode-locked lasers, which adjust the pulse time interval by adjusting the repetition frequency (repetition rate). However, traditional piezoelectric tuning methods are limited by the speed and range of mechanical adjustment, and are difficult to meet the speed, range and precision requirements of modern ultrafast science.

[0003] In recent years, the development of optical frequency comb technology has provided a new path for high-precision optical pulse manipulation. Microcavity optical frequency combs have attracted more and more attention due to their compactness and high efficiency. Due to the lack of efficient all-optical manipulation of microcavity optical frequency comb soliton pulses, applications based on manipulating the temporal position of pulses have not been fully developed. For example, it has broad application prospects in all-optical caching, ultrafast measurement, and high-precision time coding, but it has not been widely used due to current technical bottlenecks. Summary of the invention

[0004] The purpose of the present invention is to solve the problem that it is difficult to achieve accurate all-optical control of the temporal position of femtosecond soliton pulses in a microcavity optical frequency comb system, and to provide a system and method for manipulating the temporal position of soliton pulses in a microcavity optical frequency comb system.

[0005] In order to solve the deficiencies of the above-mentioned prior art, the present invention provides the following technical solutions:

[0006] A system for manipulating the time domain position of a microcavity optical frequency comb soliton pulse, which is special in that it includes a pump light source, a phase modulation unit, a microcomb generation unit, a fiber Bragg grating, a spectrometer, a time domain analysis unit, a first beam splitter, and a second beam splitter;

[0007] The pump light source is used to generate pump laser, and its output end is connected to the input end of the first beam splitter, one output end of the first beam splitter is connected to the first input end of the micro-comb generating unit, and the other output end is connected to the second input end of the micro-comb generating unit through the phase modulation unit;

[0008] The phase modulation unit includes a microwave source, a phase shifter and an electro-optical modulator, the output and input of which are connected in sequence, the microwave source is used to generate a modulation signal, the phase shifter is used to adjust the phase of the modulation signal to change the phase modulation parameter of the pump laser, and the two optical ports of the electro-optical modulator are respectively connected to the other output end of the first beam splitter and the second input end of the micro-comb generating unit, and are used to phase modulate the pump laser so that the phase of the pump laser changes;

[0009] Alternatively, the phase modulation unit comprises a microwave source with a phase modulation function and an electro-optical modulator whose output and input are connected in sequence, the microwave source with a phase modulation function is used to generate a modulation signal, and two optical ports of the electro-optical modulator are respectively connected to the other output end of the first beam splitter and the second input end of the micro-comb generating unit, and are used to modulate the phase of the pump laser through the modulation signal;

[0010] The micro-comb generating unit is used to generate a soliton optical frequency comb, and its output end is connected to the fiber Bragg grating, which is used to filter out pump light and auxiliary light. Its output end is connected to a spectrometer and a time domain analysis unit respectively through a second beam splitter, and the spectrometer is used to monitor the spectrum of the soliton optical frequency comb, and the time domain analysis unit is used to monitor the time domain position of the soliton pulse.

[0011] Furthermore, the time domain analysis unit includes a high-speed photodetector and an oscilloscope whose output and input are connected in sequence; the input end of the high-speed photodetector is connected to a second beam splitter for converting the optical signal into an electrical signal to capture the position of the soliton pulse; the oscilloscope is used to receive the electrical signal and display the time domain distribution of the soliton pulse in real time, thereby analyzing and verifying the time domain position manipulation effect of the soliton pulse.

[0012] A method for manipulating the time domain position of a microcavity optical frequency comb soliton pulse, which is special in that it comprises the following steps:

[0013] Step 1, construct the above-mentioned system for manipulating the time domain position of microcavity optical frequency comb soliton pulses, and initially set the wavelength of the pump light source;

[0014] Step 2, setting the output frequency of the microwave source, and gradually increasing the output power of the microwave source, while adjusting the micro-comb generating unit until a micro-cavity soliton optical frequency comb with locked repetition rate is generated;

[0015] Step 3: Adjust the phase parameters of the phase shifter or the phase parameters of the microwave source with phase modulation function to change the phase distribution of the pump laser, thereby dynamically controlling the change of the time domain position of the soliton pulse. At the same time, use the time domain analysis unit to record the change of the time domain position of the soliton pulse to analyze and verify the time domain position adjustment effect of the soliton pulse, thereby realizing the manipulation of the time domain position of the microcavity optical frequency comb soliton pulse.

[0016] Furthermore, in step 3, the phase parameters of the phase shifter or the phase parameters of the microwave source with phase modulation function are adjusted specifically as follows: the phase of the phase shifter or the microwave source with phase modulation function is adjusted to change between 0 and 360°, corresponding to the position change of the soliton pulse in one circle in the microcavity, so as to achieve full range arbitrary adjustment of the time domain position of the soliton pulse.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) The system for manipulating the temporal position of microcavity optical frequency comb soliton pulses of the present invention can realize full-cycle all-optical arbitrary manipulation of microcavity soliton pulses simply by modulating the phase of the pump laser. Therefore, the soliton microcomb is not only a fixed ruler in the frequency domain, but also a ruler that can be arbitrarily moved in the time domain, paving the way for a new type of all-optical delay generator.

[0019] (2) The method of manipulating the temporal position of microcavity optical frequency soliton pulses provided by the present invention can store and reconstruct information represented as a pulse sequence on the fly without the need for power-consuming photoelectric conversion. Therefore, the efficiency of optical information processing can be improved while reducing power consumption.

[0020] (3) The present invention achieves precise control of the soliton pulse position in the time domain through phase modulation, which can achieve a control accuracy of fs or even ass. This accuracy and flexibility makes it more superior in applications such as ultra-high-speed measurement, time-frequency transmission, all-optical logic operation and data scheduling, and makes up for the shortcomings of traditional fiber combs in time control accuracy.

[0021] (4) The method of manipulating the time domain position of the microcavity optical frequency comb soliton pulse of the present invention is based on locking the soliton repetition frequency. Based on the characteristics of locking the soliton repetition frequency, the pulse has extremely low time domain jitter. Therefore, in the method of encoding information with the soliton pulse sequence, there will be no bit error rate and it has strong anti-noise ability.

[0022] (5) The system and method of the present invention for manipulating the time domain position of microcavity optical frequency comb soliton pulses can be widely applied to microcavities of different wavelength bands, different materials, and different sizes, and have good versatility and universality. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the system structure for manipulating the time domain position of microcavity optical frequency comb soliton pulses according to the present invention;

[0024] Figure 2 Schematic diagram of the structure of a phase modulation unit in an embodiment of the present invention;

[0025] Figure 3 Schematic diagram of the structure of a time domain analysis unit in an embodiment of the present invention;

[0026] Figure 4 A locked repetition rate microcavity soliton optical frequency comb diagram in an embodiment of the method for manipulating the time domain position of a microcavity optical frequency comb soliton pulse of the present invention;

[0027] Figure 5 This is a time domain position diagram of the manipulated soliton in an embodiment of the present invention. The phase shifter is lowered by 45°, and the soliton pulse moves from the 0ps position to the -2.5ps position;

[0028] Figure 6 This is a time domain position diagram of the manipulated soliton in an embodiment of the present invention. The phase shifter is increased by 45°, and the soliton pulse moves from the 0ps position to the 2.5ps position;

[0029] Figure 7 This is a time domain position diagram of the full range of arbitrary manipulation of solitons in an embodiment of the present invention. The phase shifter continuously changes the phase in steps of 45°, corresponding to the time domain position of the soliton pulse.

[0030] The following are the descriptions of the reference numerals:

[0031] 1-pump light source; 2-phase modulation unit; 3-micro-comb generation unit; 4-fiber Bragg grating; 5-spectrometer; 6-time domain analysis unit; 21-microwave source; 22-phase shifter; 23-electro-optic modulator; 61-high-speed photodetector; 62-oscilloscope. DETAILED DESCRIPTION

[0032] The present invention will be further described below in conjunction with the accompanying drawings and exemplary embodiments.

[0033] Reference Figure 1 A system for manipulating the time domain position of a microcavity optical frequency comb soliton pulse comprises a pump light source 1, a phase modulation unit 2, a microcomb generation unit 3, a fiber Bragg grating 4, a spectrometer 5, a time domain analysis unit 6, a first beam splitter, and a second beam splitter.

[0034] The pump light source 1 is used to generate pump laser, and its output end is connected to the input end of the first beam splitter. One output end of the first beam splitter is connected to the first input end of the micro-comb generating unit 3 to provide continuous pump light for the micro-cavity, and the other output end is connected to the second input end of the micro-comb generating unit 3 through the phase modulation unit 2. The pump light source 1 is a narrow linewidth semiconductor laser or a narrow linewidth fiber laser. In this embodiment, the pump light source 1 is an ultra-narrow linewidth fiber laser with a linewidth of 100 Hz and an output wavelength set to 1560.4 nm.

[0035] The phase modulation unit 2 is used to perform phase modulation on the pump laser, and dynamically control the temporal position of the soliton pulse by manipulating the phase distribution of the pump laser; the phase modulation unit 2 includes a microwave source 21, a phase shifter 22 and an electro-optic modulator 23, the output and input of which are connected in sequence, such as Figure 2As shown; the microwave source 21 is used to generate a modulation signal, and the phase shifter 22 is used to adjust the phase of the modulation signal to change the phase modulation parameters of the pump laser; the two optical ports of the electro-optic modulator 23 are respectively connected to the other output end of the first beam splitter and the second input end of the micro-comb generating unit 3, and are used to phase modulate the pump laser so that the phase of the pump laser changes. In other embodiments, the phase modulation unit 2 may also include a microwave source with a phase modulation function and an electro-optic modulator, the output and input of which are connected in sequence, and the microwave source with a phase modulation function is used to generate a modulation signal and adjust the phase, which can reduce the use of the phase shifter and simplify the optical path system; the two optical ports of the electro-optic modulator are respectively connected to the other output end of the first beam splitter and the second input end of the micro-comb generating unit 3, and are used to modulate the phase of the pump laser through the modulation signal.

[0036] The micro-comb generating unit 3 is used to generate a soliton optical frequency comb, and its output end is connected to a fiber Bragg grating 4. The micro-comb generating unit 3 is an on-chip integrated micro-ring resonator or a whispering gallery mode micro-optical resonator. In this embodiment, the micro-comb generating unit 3 is a micro-ring resonator based on a high refractive index difference material, which is encapsulated in a butterfly pin housing with a temperature controller; the temperature controller is used to control the operating temperature of the micro-ring resonator to achieve stable generation of the soliton optical frequency comb.

[0037] The fiber Bragg grating 4 is used to filter out the pump light and the auxiliary light, and its output end is connected to the spectrometer 5 and the time domain analysis unit 6 respectively through the second beam splitter.

[0038] The spectrometer 5 is used to monitor the spectrum of the soliton optical frequency comb, and the time domain analysis unit 6 is used to monitor the time domain position of the soliton pulse.

[0039] Reference Figure 3 The time domain analysis unit 6 includes a high-speed photodetector 61 and an oscilloscope 62 whose output and input are connected in sequence; the input end of the high-speed photodetector 61 is connected to a second beam splitter for converting an optical signal into an electrical signal to capture the position of the soliton pulse; the oscilloscope 62 is used to receive the electrical signal output by the high-speed photodetector 61 and display the time domain distribution of the soliton pulse in real time, so as to analyze and verify the time domain position adjustment effect of the soliton pulse.

[0040] The first beam splitter and the second beam splitter are both 50:50 beam splitters.

[0041] At the same time, the present invention also provides a method for manipulating the time domain position of a microcavity optical frequency comb soliton pulse, comprising the following steps:

[0042] Step 1: Build the above-mentioned system for manipulating the time domain position of microcavity optical frequency comb soliton pulses, set the wavelength of pump light source 1 to 1560.4 nm, and use a fiber amplifier to amplify it to 900 mW to reach the optical parametric oscillation threshold;

[0043] Step 2, the output frequency of the microwave source 21 is set to 48.943 GHz, the output power of the microwave source 21 is gradually increased, and the micro-comb generating unit 3 is adjusted to generate a soliton optical frequency comb with a locked repetition rate;

[0044] like Figure 4 As shown, in the entire wavelength range, clear and equally spaced comb teeth can be observed, the microcavity repetition rate is 48.943 GHz, the corresponding time domain period is about 20 ps, ​​and the initial position of the generated soliton pulse is 0 ps;

[0045] Step 3, adjusting the phase of the phase shifter 22 to change between 0 and 360 degrees to change the phase distribution of the pump laser, thereby dynamically controlling the change of the time domain position of the soliton pulse;

[0046] Specifically, the phase shifter 22 is lowered by 45°, and the soliton pulse moves from the 0ps position to the -2.5ps position, as shown in FIG. Figure 5 As shown; the phase shifter 22 increases by 45°, and the soliton pulse moves from the 0ps position to the 2.5ps position, as shown Figure 6 As shown; the phase shifter 22 changes in the 0-360° phase, which corresponds to the position change of the soliton pulse in the microcavity, and can achieve full range of arbitrary adjustment of the pulse time domain position, such as Figure 7 As shown;

[0047] By changing the output frequency of the microwave source 21 to an integer multiple of the repetition rate and adjusting the phase shifter 22, several times the repetition rate will correspond to the all-optical manipulation of several solitons;

[0048] Taking six solitons as an example, first adjust the pump laser frequency to generate a six-soliton optical frequency comb, then set the output frequency of the microwave source 21 to 293.658 GHz, and adjust the phase shifter 22 to achieve time domain position manipulation of the six-soliton pulses.

[0049] The principle of manipulating the time domain position of the microcavity optical frequency comb soliton pulse in the present invention is:

[0050] After generating a soliton optical frequency comb with locked repetition rate, the phase distribution of the pump laser is changed by adjusting the phase of the phase shifter 22. When the pump laser enters the microcavity, the phase distribution will be imprinted on the background wave in the cavity. When the soliton pulse meets the background wave, a drift speed will be generated under the action of the phase gradient, and the soliton pulse will drift to the potential well position generated by the modulation, and the potential well will firmly capture the soliton pulse. The position of the potential well is determined by the phase distribution of the background wave in the cavity, and the potential well position will be deterministically changed when the phase of the phase shifter 22 is adjusted. The 0~360° phase change corresponds to the position change of the soliton pulse in one circle in the microcavity, realizing the full range of arbitrary adjustment of the pulse time domain position.

Claims

1. A system for manipulating the temporal position of microcavity optical frequency comb soliton pulses, characterized by: It comprises a pump light source (1), a phase modulation unit (2), a micro-comb generating unit (3), a fiber Bragg grating (4), a spectrometer (5), a time domain analysis unit (6), a first beam splitter, and a second beam splitter; The pump light source (1) is used to generate pump laser light, and its output end is connected to the input end of the first beam splitter, one output end of the first beam splitter is connected to the first input end of the micro-comb generating unit (3), and the other output end is connected to the second input end of the micro-comb generating unit (3) through the phase modulation unit (2); The phase modulation unit (2) comprises a microwave source (21), a phase shifter (22) and an electro-optic modulator (23) whose output and input are connected in sequence, the microwave source (21) is used to generate a modulation signal, the phase shifter (22) is used to adjust the phase of the modulation signal to change the phase modulation parameter of the pump laser, and the two optical ports of the electro-optic modulator (23) are respectively connected to the other output end of the first beam splitter and the second input end of the micro-comb generating unit (3) to perform phase modulation on the pump laser so that the phase of the pump laser changes; Alternatively, the phase modulation unit (2) comprises a microwave source with a phase modulation function and an electro-optical modulator whose output and input are connected in sequence, the microwave source with a phase modulation function is used to generate a modulation signal, and two optical ports of the electro-optical modulator are respectively connected to the other output end of the first beam splitter and the second input end of the micro-comb generating unit (3) for modulating the phase of the pump laser through the modulation signal; The micro-comb generating unit (3) is used to generate a soliton optical frequency comb, and its output end is connected to the fiber Bragg grating (4), the fiber Bragg grating (4) is used to filter out pump light and auxiliary light, and its output end is respectively connected to a spectrometer (5) and a time domain analysis unit (6) through a second beam splitter, the spectrometer (5) is used to monitor the spectrum of the soliton optical frequency comb, and the time domain analysis unit (6) is used to monitor the time domain position of the soliton pulse.

2. A system for manipulating the time domain position of microcavity optical frequency comb soliton pulses according to claim 1, characterized in that: The time domain analysis unit (6) comprises a high-speed photodetector (61) and an oscilloscope (62) whose output and input are connected in sequence; the input end of the high-speed photodetector (61) is connected to one of the output ends of the second beam splitter, and is used to convert the optical signal into an electrical signal to capture the position of the soliton pulse; the oscilloscope (62) is used to receive the electrical signal and display the time domain distribution of the soliton pulse in real time, so as to analyze and verify the time domain position manipulation effect of the soliton pulse.

3. A method for manipulating the temporal position of a microcavity optical frequency comb soliton pulse, characterized in that: The steps include: Step 1, constructing the system for manipulating the time domain position of microcavity optical frequency comb soliton pulses as described in claim 1, and initially setting the wavelength of the pump light source (1); Step 2, setting the output frequency of the microwave source (21), and gradually increasing the output power of the microwave source (21), while adjusting the micro-comb generating unit (3) until a micro-cavity soliton optical frequency comb with locked repetition frequency is generated; Step 3: Adjust the phase parameters of the phase shifter (22) or the phase parameters of the microwave source (21) with phase modulation function to change the phase distribution of the pump laser, thereby dynamically controlling the change of the time domain position of the soliton pulse. At the same time, use the time domain analysis unit (6) to record the change of the time domain position of the soliton pulse to analyze and verify the time domain position adjustment effect of the soliton pulse, thereby realizing the manipulation of the time domain position of the microcavity optical frequency comb soliton pulse.

4. The method for manipulating the time domain position of a microcavity optical frequency comb soliton pulse according to claim 3, characterized in that: In step 3, the phase parameter of the phase shifter (22) or the phase parameter of the microwave source (21) with phase modulation function is specifically adjusted as follows: The phase of the phase shifter (22) or the microwave source (21) with phase modulation function is adjusted to change between 0 and 360 degrees, corresponding to the position change of the soliton pulse in one circle in the microcavity, so as to achieve full range arbitrary adjustment of the time domain position of the soliton pulse.

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