Flat low-noise multi-wavelength laser generation system and method based on Brillouin cavity

Abstract

The invention discloses a flat low-noise multi-wavelength laser generation system and method based on a Brillouin cavity. The system comprises a multi-wavelength pumping laser generation branch, a Brillouin optical fiber ring cavity and a frequency shift injection locking branch. The multi-wavelength pumping laser generation branch is used for generating and outputting flat multi-wavelength pumping laser and comprises a first distributed feedback laser, a first polarization controller, a first optical fiber circulator, a first multi-wavelength generator and a spectrum shaper; and the Brillouin optical fiber ring cavity is connected with the multi-wavelength pumping laser generation branch and the frequency shift injection locking branch through a second circulator, and is used for generating and finally outputting multi-wavelength Brillouin laser. The invention generates multi-wavelength laser with the advantages of low noise, flat spectrum and the like, and is suitable for application scenes of low-phase noise signal generation, high-dynamic range signal processing and the like in a microwave photon system.

Description

Technical Field

[0001] This invention relates to the field of multi-wavelength laser generation technology, and more particularly to a flat, low-noise multi-wavelength laser source generation system and method based on a Brillouin cavity. Background Technology

[0002] Multi-wavelength light sources with flat spectra and ultra-low noise characteristics play a crucial role in fields such as optical communication, precision measurement, and microwave photonics. By effectively controlling the power flatness between comb teeth and suppressing comb phase noise, these light sources can ensure multi-channel uniformity, signal integrity, and weak signal detection capabilities, thereby meeting the core requirements of high-performance systems in these fields.

[0003] Traditional distributed feedback laser arrays generate multi-wavelength outputs through independent lasers, but they suffer from drawbacks such as weak coherence and poor comb phase noise. Spontaneous emission noise also has adverse effects, making them unsuitable for high-precision, low-noise applications. Optical frequency combs (including electro-optic combs, microcavity optical frequency combs, and cyclic frequency shifting loop structures) generate discrete wavelength components through periodic structures. However, while electro-optic combs are simple in structure, they accumulate radio frequency phase noise; cyclic frequency shifting loops generate power jitter during operation; and microcavity optical combs have uneven power distribution. These problems collectively hinder the achievement of both spectral flatness and low phase noise within the comb spectrum. To address these issues, multiple wavelengths can be locked to various optical resonators. For example, using a Pound-Drever-Hall to lock a high-precision reference cavity provides excellent stability, but requires complex laser frequency modulation and precise optical path calibration. CN118676720A discloses a low-noise frequency-tunable optical microwave source system based on a Brillouin fiber cavity. However, the locking structure, which combines frequency-shifting optical injection locking with modulation sideband optical injection locking, can only achieve two wavelength outputs and has a complex structure, limiting its multi-wavelength output capability in a wider range of applications. Summary of the Invention

[0004] Purpose of the invention: The purpose of this invention is to provide a flat, low-noise, multi-wavelength laser generation system and method based on a Brillouin cavity, which can generate multi-wavelength laser signals with ultra-low noise and ultra-high flatness.

[0005] Technical solution: A flat, low-noise, multi-wavelength laser generation system based on a Brillouin cavity, characterized in that it includes a multi-wavelength pump laser generation branch, a Brillouin fiber ring cavity, and a frequency-shift injection-locked branch;

[0006] The multi-wavelength pump laser generation branch is used to generate and output an externally pumped laser with a flat surface, and includes a first distributed feedback laser, a first polarization controller, a first fiber circulator, a multi-wavelength generator, and a spectral shaper connected in sequence.

[0007] The Brillouin fiber ring cavity is connected to the multi-wavelength pump laser generation branch and the frequency shift injection locking branch through a second circulator. The Brillouin fiber ring cavity is used to generate and ultimately output multi-wavelength Brillouin laser.

[0008] The frequency-shift injection locking branch is used to lock the relative position of the output wavelength of the first distributed feedback laser with the cavity longitudinal mode and to narrow the linewidth.

[0009] Furthermore, the Brillouin fiber optic cavity includes a Brillouin gain fiber and a first fiber coupler respectively connected to the two ends of the second circulator, and an isolator, an optical amplifier and a third polarization controller are also provided between the Brillouin gain fiber and the first fiber coupler.

[0010] Furthermore, the frequency shift injection lockout branch is connected between the first fiber coupler and the first circulator.

[0011] Furthermore, the frequency shift injection lockout branch includes a fourth polarization controller, a second filter, and a frequency shifter connected between the first fiber coupler and the first circulator.

[0012] The present invention discloses a method for generating flat, low-noise, multi-wavelength lasers based on a Brillouin cavity, employing the aforementioned flat, low-noise, multi-wavelength laser generation system based on a Brillouin cavity, comprising the following steps:

[0013] Step 1: An initial laser is generated by a first distributed feedback laser. The initial laser passes through a first polarization controller and a first fiber optic circulator and enters a multi-wavelength generator to generate a multi-wavelength comb spectrum. After the multi-wavelength comb spectrum is shaped by a spectral shaper, a flat external multi-wavelength pump laser is formed.

[0014] Step 2: The external multi-wavelength pump laser passes through the Brillouin gain fiber in the Brillouin fiber ring cavity to generate a multi-wavelength Brillouin laser that propagates in the opposite direction.

[0015] Step 3: The multi-wavelength Brillouin laser is divided into one laser and two lasers;

[0016] One laser beam enters the frequency-shift injection-locked branch, and after filtering and frequency shifting, a laser beam near the initial laser frequency is obtained. The frequency-shift injection-locked mechanism is used to lock the relative position of the output wavelength of the first distributed feedback laser with the cavity longitudinal mode and to narrow the linewidth.

[0017] The two laser beams circulate within a Brillouin fiber optic ring, and a small portion of the circulating light within the cavity is split by a second fiber coupler to achieve multi-wavelength Brillouin laser output.

[0018] Furthermore, in the frequency-shift injection-locked branch, one laser path is optimized for polarization by a fourth polarization controller and a second filter, filtering out the Brillouin laser generated by the first distributed feedback laser in the Brillouin fiber ring cavity. After passing through a frequency shifter, it is injected into the first distributed feedback laser, transferring the narrow linewidth characteristic of the Brillouin laser to the pump, thus narrowing the linewidth of the secondary laser output by the first distributed feedback laser after injection; and maintaining the relative position between the initial pump laser and the cavity longitudinal mode, locking the wavelength output by the first distributed feedback laser.

[0019] The secondary laser output from the first distributed feedback laser after the wavelength is locked enters the first distributed feedback laser again after passing through the Brillouin gain fiber and the frequency shift injection locking branch, which makes the linewidth of the output laser narrower again.

[0020] After several cycles, the output wavelength of the first distributed feedback laser is locked relative to the cavity longitudinal mode, and the linewidth is narrowed to the limit.

[0021] Furthermore, the secondary laser output from the first distributed feedback laser after wavelength locking circulates in the Brillouin fiber loop cavity after passing through the Brillouin gain fiber. First, a third polarization controller controls the polarization of the multi-wavelength Brillouin laser circulating within the cavity, thereby controlling the balance between gain and loss within the cavity. An optical amplifier generates gain to compensate for the cavity loss of the Brillouin fiber loop cavity, reducing the stimulated Brillouin scattering threshold condition and achieving multi-wavelength Brillouin laser output. Then, an isolator is used again to isolate the reverse high-order Brillouin laser generated after the Brillouin laser passes through the Brillouin gain fiber again. Finally, a second fiber coupler splits a small portion of the circulating light within the cavity to achieve multi-wavelength Brillouin laser output.

[0022] The electronic device of the present invention includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the computer program is loaded into the processor, it implements the method for generating flat, low-noise, multi-wavelength lasers based on a Brillouin cavity.

[0023] The computer-readable storage medium of the present invention stores a computer program, which, when executed by a processor, implements the method for generating flat, low-noise, multi-wavelength lasers based on a Brillouin cavity.

[0024] The computer program product of the present invention includes a computer program that, when executed by a processor, implements the method for generating flat, low-noise, multi-wavelength lasers based on a Brillouin cavity.

[0025] Beneficial Effects: Compared with existing technologies, the advantages of this invention are as follows: This invention achieves flat, low-noise, multi-wavelength laser source output based on a Brillouin cavity, solving the problem that existing multi-wavelength laser signals are difficult to simultaneously achieve low noise and flatness, and eliminating the need for complex active feedback to maintain stable system operation. This invention can generate multi-wavelength lasers with advantages such as low noise and spectral flatness, making it particularly suitable for applications such as low phase noise signal generation and high dynamic range signal processing in microwave photonics systems. It is of great significance for promoting the development of advanced radar systems and next-generation communication technologies. Attached Figure Description

[0026] Figure 1 This is a structural diagram of the multi-wavelength laser generation system of the present invention.

[0027] Figure 2 This is a structural diagram of a multi-wavelength laser generation system according to an embodiment of the present invention.

[0028] Figure 3 The image shows the spectrum of the multi-wavelength Brillouin laser generated by the external multi-wavelength pump laser and the Brillouin laser cavity in an embodiment of the present invention.

[0029] Figure 4 This is a graph showing the frequency stability data of five external multi-wavelength pump lasers and the first distributed feedback laser in an unlocked state, along with five multi-wavelength Brillouin lasers, over a certain period of time in an embodiment of the present invention.

[0030] Figure 5 This is a comparison chart of phase noise data between low-noise microwave signals generated by external multi-wavelength pump lasers and multi-wavelength Brillouin lasers in an embodiment of the present invention. Detailed Implementation

[0031] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0032] like Figure 1 As shown, the flat, low-noise, multi-wavelength laser generation system based on a Brillouin cavity includes a multi-wavelength pump laser generation branch 1, a Brillouin fiber ring cavity 2, and a frequency-shift injection locking branch 3. The multi-wavelength pump laser generation branch 1 is used for laser generation and output, outputting a flat external multi-wavelength pump laser. The spacing of the external multi-wavelength pump lasers is set to equal or unequal spacing depending on the actual situation. The Brillouin fiber ring cavity 2 is an extended loop with Brillouin gain fiber (BGF) 21, used to generate low-noise, flat multi-wavelength Brillouin light. The frequency-shift injection locking branch 3 is used to lock the relative position of the laser output wavelength and the cavity longitudinal mode and to narrow the linewidth. Figure 1 The arrows in the diagram indicate the direction of the laser beam.

[0033] To ensure effective output of the multi-wavelength Brillouin laser, the external multi-wavelength pump laser and the cavity longitudinal modes must meet specific matching conditions: the Brillouin gain regions excited by different wavelength components of the external multi-wavelength pump laser within the Brillouin fiber ring cavity 2 are wavelength-dependent, meaning the position of each gain region is determined by the distribution of its corresponding pump wavelength and shifts with changes in that wavelength. Based on this characteristic, the pump wavelength must be precisely adjusted to ensure that the longitudinal modes of the Brillouin fiber ring cavity are always aligned near the peak values ​​of their respective gain regions, thereby guaranteeing stable output of the multi-wavelength Brillouin laser in the cavity longitudinal modes.

[0034] The multi-wavelength pumped laser generation branch 1 includes a first distributed feedback laser (DFB) 11, a first polarization controller (PC1) 12, a first circulator (CIR1) 13, a multi-wavelength generator (MWG) 16, a spectral shaper (SS) 17, an erbium-doped fiber amplifier (EDFA) 18, and a second polarization controller (PC2) 19 connected in sequence. The first distributed feedback laser 11 is a fixed-wavelength or tunable distributed feedback laser; the first polarization controller 12 is used to control the polarization state of the post-frequency shift sideband of the first distributed feedback laser 11 to optimize the injection effect.

[0035] As a preferred embodiment, such as Figure 2 As shown, the multi-wavelength generator 16 is a first electro-optic modulator (EOM1) 15. The first radio frequency signal source (RF1) 14 drives the first electro-optic modulator 15 to perform frequency shifting. The radio frequency signal of the first electro-optic modulator 15 is the microwave signal output by the radio frequency signal source 16. When the microwave signal satisfies an integer multiple of the longitudinal mode spacing of the Brillouin ring cavity, the output of multi-wavelength Brillouin laser can be realized. The first electro-optic modulator 15 is used to electro-optically modulate the laser output by the first distributed feedback laser 11 to generate an electro-optic comb spectrum. After the comb spectrum is shaped by the spectrum shaper 17, it forms a flat multi-wavelength spectrum, which is used as the pump source of the multi-wavelength Brillouin laser and enters the Brillouin fiber ring cavity 2.

[0036] As a preferred embodiment, such as Figure 2 As shown, the frequency shifter 31 consists of a second electro-optic modulator (EOM2) 29, a second radio frequency signal source (RF2) 30, and a first filter 32. The second electro-optic modulator 29 is used to electro-optically modulate the Brillouin laser at the center carrier filtered out by the second filter 28 to generate symmetrical sidebands. After passing through the first filter (TOF1) 32, a single sideband with a frequency position close to that of the first distributed feedback laser 11 is filtered out, thereby completing the frequency shift injection lock.

[0037] The Brillouin fiber cavity 2 is connected to the multi-wavelength pump laser generation branch 1 and the frequency-shift injection-locked branch 3 via a second circulator (CIR2) 20. The two ends of the second circulator 20 are connected to the Brillouin gain fiber 21 and the first fiber coupler (OC1) 26, respectively. An isolator (ISO) 22, an optical amplifier (AMP) 23, a second fiber coupler (OC2) 24, and a third polarization controller (PC3) 25 are arranged between the Brillouin gain fiber 21 and the first fiber coupler 26. The flat multi-wavelength pump laser generated by the multi-wavelength pump laser generation branch 1 enters the Brillouin gain fiber 21 through the second circulator 20, generating a back-propagating multi-wavelength Brillouin laser. This laser then sequentially passes through the second circulator 20, the first fiber coupler 28, the third polarization controller 27, the optical amplifier 23, and the isolator 22 before re-entering the Brillouin gain fiber 21. This multi-wavelength Brillouin laser is a first-order Brillouin laser.

[0038] In this system, Brillouin gain fiber 21 is used to generate backpropagating multi-wavelength Brillouin laser light. Optical amplifier 23 generates gain to compensate for the intracavity loss of the Brillouin fiber ring cavity 2, thereby reducing the threshold of stimulated Brillouin scattering. Isolator 22 is used to isolate the backpropagating higher-order Brillouin laser light generated after the Brillouin laser light passes through Brillouin gain fiber 21 again. Third polarization controller 25 is used to control the polarization within the Brillouin laser cavity, thereby controlling the balance between intracavity gain and loss. First fiber coupler 26 splits the passing multi-wavelength Brillouin laser light into two parts: one part enters the frequency-shift injection-locked branch 3, and the other part enters the third polarization controller 25, circulating within the cavity.

[0039] The frequency shift injection locking branch 3 is connected between the first fiber coupler 26 and the first circulator 13. The frequency shift injection locking branch 3 is used to lock the wavelength of the first distributed feedback laser 11 and transmit its narrow linewidth characteristics. The frequency shift injection locking branch 3 includes a fourth polarization controller (PC4) 27 connected to the first fiber coupler 26, and a second filter (TOF2) 28, a second electro-optic modulator 29, and a first filter 32 connected in sequence. The first filter 32 is also connected to the first circulator 13.

[0040] The fourth polarization controller 27 is used to maintain the polarization state of the frequency-shifted injected Brillouin laser; the second electro-optic modulator 29 is used to shift the frequency of the Brillouin light so that it is close to the frequency of the original output laser from the first distributed feedback laser 11. The second filter 28 is used to filter and retain the Brillouin laser generated by the first distributed feedback laser 11 in the Brillouin fiber ring cavity 2, and the first filter 32 is used to filter and retain the laser with a frequency close to that generated by the first distributed feedback laser 11.

[0041] Specifically, both the first circulator 13 and the second circulator 20 include three ports, designated as port a, port b, and port c, with unidirectional conduction from port a to port b and from port b to port c. During operation, the laser will only travel from port a to port b or from port b to port c. Port a of the first circulator 12 is connected to the first filter 32, port b is connected to the first polarization controller 12, and port c is connected to the first electro-optic modulator 15. Port a of the second circulator 20 is connected to the second polarization controller 19, port b is connected to the Brillouin gain fiber 21, and port c is connected to the first fiber coupler 26.

[0042] The power flatness of the multi-wavelength Brillouin laser output by the second fiber coupler 24 in the ring cavity is mainly affected by the flatness of the external multi-wavelength pump laser after shaping by the first electro-optic modulator 15 and the spectral shaper 17, as well as the gain flatness of the optical amplifier 18.

[0043] The method for generating flat, low-noise, multi-wavelength lasers based on Brillouin cavities according to the present invention includes the following steps.

[0044] S1: An initial laser beam is generated by the first distributed feedback laser 11. The initial laser beam is the output laser of the unlocked first distributed feedback laser 11. The initial laser beam passes through the first polarization controller 12 and the first circulator 13 and enters the first electro-optic modulator 15 for electro-optic modulation to generate an electro-optic comb spectrum. After the electro-optic comb spectrum is shaped by the spectrum shaper 17, it forms a flat external multi-wavelength pump laser, which serves as the pump source for the multi-wavelength Brillouin laser and enters the Brillouin fiber ring cavity 2.

[0045] S2, the external multi-wavelength pump laser generates a multi-wavelength Brillouin laser that propagates in the opposite direction through the Brillouin gain fiber 21; the multi-wavelength Brillouin laser passes through the second circulator 20, the first fiber coupler 28, the third polarization controller 27, the optical amplifier 23, and the isolator 22 in sequence and re-enters the Brillouin gain fiber 21, thereby making the multi-wavelength Brillouin laser circulate in the Brillouin fiber ring cavity 2.

[0046] S3: The initial multi-wavelength Brillouin laser is split into one laser and two lasers after passing through the first fiber coupler 26; one laser enters the frequency shift injection lock branch 3, and the two lasers circulate in the Brillouin fiber ring cavity 2 through the third polarization controller 25.

[0047] S4: One laser beam entering the frequency-shifting injection-locked branch 3 is optimized by the fourth polarization controller 27 and then filtered by the second filter 28 to filter out the Brillouin laser generated by the first distributed feedback laser (11) in the Brillouin fiber ring cavity. It is then frequency-shifted and filtered by the second frequency shifter 32 and the first filter 32 to obtain a laser beam with a frequency close to the initial laser generated by the first distributed feedback laser 11, which is called the injection light. The injection light enters the first distributed feedback laser 11 through the first circulator 13 to lock the wavelength of the first distributed feedback laser 11 and the narrow linewidth transmission characteristics.

[0048] The two lasers entering the Brillouin fiber ring cavity 2 first pass through the third polarization controller 25 to control the polarization of the multi-wavelength Brillouin laser circulating in the cavity, thereby controlling the balance between gain and loss in the cavity. The optical amplifier generates gain to compensate for the cavity loss of the Brillouin fiber ring cavity 2, thereby reducing the stimulated Brillouin scattering threshold condition to realize the output of multi-wavelength Brillouin laser. Then, it passes through the isolator 22 again to isolate the reverse high-order Brillouin laser generated after the Brillouin laser passes through the Brillouin gain fiber 21 again.

[0049] After the wavelength is locked, the laser output by the first distributed feedback laser 11 is called the secondary laser. The secondary laser passes through the Brillouin gain fiber 21 and the frequency shift injection locking branch 3 again before entering the first distributed feedback laser 11, which again narrows the linewidth of the laser output by the first distributed feedback laser 11. After several cycles, the output wavelength of the first distributed feedback laser 11 can be locked relative to the cavity longitudinal mode and the linewidth can be narrowed to the limit.

[0050] Finally, a small portion of the intracavity circulating light is split into 24 beams by the second fiber coupler to achieve the output of multi-wavelength Brillouin laser, and its performance can be characterized.

[0051] The method described in this invention will be verified through specific experiments below.

[0052] In this experiment, the initial first distributed feedback laser 11 was set to approximately 1550.100 nm.

[0053] After the system is set up, the first distributed feedback laser 11 is turned on. The initial laser emitted passes through the first fiber circulator 13 and the first electro-optic modulator 15 into the spectral shaper 17, which uses a custom tunable optical filter. It then enters the fiber optic ring cavity through the erbium-doped fiber amplifier 18. In the Brillouin fiber optic ring cavity, it enters the Brillouin gain fiber 21, generating a multi-wavelength Brillouin laser that propagates in the opposite direction. The laser is then output through the first fiber coupler 26. A portion of the output light passes through the fourth polarization controller 27 and the second filter 28 into the second electro-optic modulator 29 and the first filter 32. The radio frequency signal frequency is the Brillouin frequency shift value corresponding to this wavelength, which is approximately 9.383 GHz. The narrow bandwidth filter is adjusted to achieve a side-mode rejection ratio of 20 dB. The frequency-shifted sidebands return to the first distributed feedback laser 11 through the first circulator 13, completing the frequency-shifted light injection locking. Another portion of the light circulates within the Brillouin fiber ring cavity 2. First, a third polarization controller 25 controls the polarization of the multi-wavelength Brillouin laser as it circulates within the cavity, thereby controlling the balance between gain and loss. An optical amplifier 23 generates gain to compensate for the intracavity loss of the Brillouin fiber ring cavity 2, thus reducing the stimulated Brillouin scattering laser threshold condition to achieve multi-wavelength Brillouin laser output. Then, an isolator 22 isolates the Brillouin laser from the reverse high-order Brillouin laser generated after it passes through the Brillouin gain fiber 21. Finally, a small portion of the circulating light within the cavity is split by a second fiber coupler 24 to achieve the output of the multi-wavelength Brillouin laser.

[0054] Reference Figure 3 The spectra of the external multi-wavelength pump laser output from branch 1 and the multi-wavelength Brillouin laser output from the Brillouin fiber ring cavity 2 can be observed. Figure 3 In the image (a), the output spectrum of the initial external multi-wavelength pump laser is shown. After optimization by the spectrum shaper 17, the power of each pump wavelength is uniform. Figure 3 (b) corresponds to the spectrum of the multi-wavelength Brillouin laser output by the second fiber coupler 24. It was observed that the peak power fluctuation between the external multi-wavelength pump laser and the multi-wavelength Brillouin laser was less than 1 dB; specifically, a multi-wavelength output with a repetition frequency of 17.95 GHz can be achieved, and its output power uniformity is mainly determined by the gain spectrum of the external amplifier; the small spectral differences existing in the pump source are amplified by the gain shaping effect of the erbium-doped fiber amplifier 18, which directly affects the flatness of the final Brillouin laser.

[0055] Figure 4 The results of frequency noise characterization of five pump lines and their corresponding multi-wavelength Brillouin lasers using a delayed self-heterodyne interferometer are presented. The interferometer includes a single-mode fiber delay path and a 40 MHz acousto-optic modulator for reference frequency shift. Figure 4(a) shows the frequency noise characterization results of the initial multi-wavelength pump lasers. The white frequency noise floor of the five independently measured multi-wavelength pump lasers is 100 Hz² / Hz—a noise suppression effect of four orders of magnitude compared to the unlocked distributed feedback pump laser. Meanwhile, Figure 4 All multi-wavelength Brillouin laser outputs in (b) exhibit excellent phase stability (< 10 at a 100 kHz offset). -1 (Hz² / Hz), this result confirms that the spectrally flattened multi-wavelength light source achieved through this cascade structure possesses excellent coherence across the entire wavelength range.

[0056] Phase noise characterization is a key indicator for evaluating the performance of multi-wavelength light sources. To quantify the phase noise of the repetition frequency of the generated multi-wavelength light, Figure 5 A dual-wavelength delayed self-heterodyne interferometry system was used to measure the repetition frequency phase noise of the initial flat multi-wavelength pump laser (blue curve) and the optimized flat low-noise multi-wavelength Brillouin fiber laser (purple curve). Experimental results show that at a 10 kHz offset frequency, the repetition frequency phase noise of the initial external multi-wavelength pump laser is −78 dBc / Hz; in contrast, the phase noise of the flat low-noise multi-wavelength Brillouin laser at the same offset frequency is significantly suppressed, reduced to −114 dBc / Hz. This result fully demonstrates that the multi-wavelength pump laser generated by this invention has superior phase noise performance. The significant reduction in phase noise highlights the effectiveness of the frequency-shifting optical injection locking mechanism in transferring the low-noise characteristics of the Brillouin laser to the pump laser, ensuring high spectral purity in all wavelength channels. In summary, due to its extremely low noise level, this scalable cascaded narrowing structure provides an effective way to develop ultra-low noise multi-wavelength light sources, which are indispensable for coherent communication, precision metrology, and distributed sensing systems.

[0057] The electronic device of the present invention includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the computer program is loaded into the processor, it implements the method for generating flat, low-noise, multi-wavelength lasers based on a Brillouin cavity.

[0058] The computer-readable storage medium of the present invention stores a computer program, which, when executed by a processor, implements the method for generating flat, low-noise, multi-wavelength lasers based on a Brillouin cavity.

[0059] The computer program product of the present invention includes a computer program that, when executed by a processor, implements the method for generating flat, low-noise, multi-wavelength lasers based on a Brillouin cavity.

[0060] The computer-readable storage medium may include RAM, ROM, EEPROM, CD-ROM or other optical disc storage devices, magnetic disk storage devices or other magnetic storage devices, flash memory or any other medium that can be used to store program code in the form of instructions or data structures and is accessible by a computer.

[0061] The processor is used to execute a computer program stored in memory to implement the various steps in the methods described in the above embodiments.

Claims

1. A flat, low-noise, multi-wavelength laser generation system based on a Brillouin cavity, characterized in that, It includes a multi-wavelength pump laser generation branch (1), a Brillouin fiber ring cavity (2), and a frequency shift injection lock branch (3). The multi-wavelength pump laser generation branch (1) is used to generate and output a flat external multi-wavelength pump laser, including a first distributed feedback laser (11), a first polarization controller (12), a first fiber circulator (13), a multi-wavelength generator (16), and a spectrum shaper (17) connected in sequence. The Brillouin fiber ring cavity (2) is connected to the multi-wavelength pump laser generation branch (1) and the frequency shift injection lock branch (3) through the second circulator (20). The Brillouin fiber ring cavity (2) is used to generate and finally output multi-wavelength Brillouin laser. The frequency shift injection locking branch (3) is used to lock the output wavelength of the first distributed feedback laser (11) relative to the cavity longitudinal mode and to narrow the linewidth.

2. The flat, low-noise, multi-wavelength laser generation system based on a Brillouin cavity according to claim 1, characterized in that, The Brillouin fiber optic cavity (2) includes a Brillouin gain fiber (21) and a first fiber coupler (26) respectively connected to the two ends of the second circulator (20). An isolator (22), an optical amplifier (23) and a third polarization controller (25) are also provided between the Brillouin gain fiber (21) and the first fiber coupler (26).

3. The planar low-noise multi-wavelength laser generation system based on a Brillouin cavity according to claim 2, characterized in that, The frequency shift injection lock branch (3) is connected between the first fiber coupler (26) and the first circulator (13).

4. The flat, low-noise, multi-wavelength laser generation system based on a Brillouin cavity according to claim 3, characterized in that, The frequency shift injection lock branch (3) includes a fourth polarization controller (27), a second filter (28), and a frequency shifter (31) connected between the first fiber coupler (26) and the first circulator (13).

5. A method for generating flat, low-noise, multi-wavelength lasers based on a Brillouin cavity, characterized in that, The flat, low-noise, multi-wavelength laser generation system based on a Brillouin cavity as described in any one of claims 1-4 includes the following steps: Step 1: An initial laser is generated by a first distributed feedback laser (11). The initial laser passes through a first polarization controller (12) and a first fiber circulator (13) and enters a multi-wavelength generator (16) to generate a multi-wavelength comb spectrum. The multi-wavelength comb spectrum is shaped by a spectral shaper (17) to form a flat external multi-wavelength pump laser. Step 2: The external multi-wavelength pump laser passes through the Brillouin gain fiber (21) in the Brillouin fiber ring cavity (2) to generate a multi-wavelength Brillouin laser that propagates in the opposite direction. Step 3: The multi-wavelength Brillouin laser is divided into one laser and two lasers; One laser beam enters the frequency shift injection locking branch (3), and after filtering and frequency shifting, a laser beam near the initial laser frequency is obtained. The frequency shift injection locking mechanism is used to lock the relative position of the output wavelength of the first distributed feedback laser (11) with the cavity longitudinal mode and to narrow the linewidth. The two laser beams circulate in the Brillouin fiber ring cavity (2), and a small portion of the circulating light within the cavity is split by the second fiber coupler (24) to achieve the output of multi-wavelength Brillouin lasers.

6. The method for generating flat, low-noise, multi-wavelength lasers based on a Brillouin cavity according to claim 5, characterized in that, In the frequency shift injection locking branch (3), one laser path is optimized for polarization state and filtered out by the fourth polarization controller (27) and the second filter (28) to filter out the Brillouin laser generated by the first distributed feedback laser (11) in the Brillouin fiber ring cavity (2). After passing through the frequency shifter (31), it is injected into the first distributed feedback laser (11), which transmits the narrow linewidth characteristic of the Brillouin laser to the pump, so that the linewidth of the secondary laser output by the first distributed feedback laser (11) after injection becomes narrower; and the relative position between the initial pump laser and the cavity longitudinal mode is maintained, locking the wavelength output by the first distributed feedback laser (11). The secondary laser output from the first distributed feedback laser (11) after the wavelength is locked enters the first distributed feedback laser (11) again through the Brillouin gain fiber (21) and the frequency shift injection locking branch (3), which makes the output laser linewidth narrower again. After several cycles, the output wavelength of the first distributed feedback laser (11) is locked relative to the cavity longitudinal mode and the linewidth is narrowed to the limit.

7. The method for generating flat, low-noise, multi-wavelength lasers based on a Brillouin cavity according to claim 6, characterized in that, The secondary laser output from the first distributed feedback laser (11) after wavelength locking circulates in the Brillouin fiber ring cavity (2) after passing through the Brillouin gain fiber (21). First, the polarization of the multi-wavelength Brillouin laser circulating in the cavity is controlled by the third polarization controller (25), thereby controlling the balance between gain and loss in the cavity. The optical amplifier (23) is used to generate gain to compensate for the cavity loss of the Brillouin fiber ring cavity (2), so as to reduce the stimulated Brillouin scattering threshold condition and realize the multi-wavelength Brillouin laser output. Then, the Brillouin laser is isolated again by isolator (22) and then the reverse high-order Brillouin laser generated after passing through the Brillouin gain fiber (21) is isolated again; finally, the output of multi-wavelength Brillouin laser is achieved by splitting a small portion of the cavity circulating light through the second fiber coupler (24).

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the computer program is loaded into the processor, it implements the method for generating flat, low-noise, multi-wavelength lasers based on a Brillouin cavity according to any one of claims 5-7.

9. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the method for generating flat, low-noise, multi-wavelength lasers based on a Brillouin cavity according to any one of claims 5-7.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the method for generating flat, low-noise, multi-wavelength lasers based on a Brillouin cavity according to any one of claims 5-7.

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