High-compression bright compression state light source with all-fiber structure

Abstract

The invention provides a high-compression-degree bright compression state light source of an all-fiber structure, and relates to the technical field of quantum optics and quantum information, laser enters a first beam splitter after passing through an isolator, and a large-proportion part of the laser after beam splitting enters a frequency doubling medium to generate pump light; a small-proportion part of the laser enters a second beam splitter; the pump light enters the waveguide resonant cavity after passing through the second phase modulator; one beam of light split by the second beam splitter is used as background light for subsequent detection, and the other beam of light split by the second beam splitter is used as signal light of the bright compressed state light source; signal light passes through the first phase modulator, then enters the waveguide resonant cavity, and is filtered by the narrow-band filter, and then a bright compressed state optical signal is output; the detector monitors the intensity of an optical signal returned by the waveguide resonant cavity in real time, one path is input to the first servo control system, and the wavelength of the demodulated feedback control laser is locked with the waveguide resonant cavity; one path is input to a second servo control system, and demodulation feedback is input to a first phase modulator, so that relative phase locking of the pump light and the signal light is realized.

Description

Technical Field

[0001] The present invention proposes a high-compression bright compressed-state light source with an all-fiber structure, and relates to the fields of quantum optics and quantum information technology. Background Art

[0002] With the development and maturity of squeezed-state light field generation technology, its related applications have also rapidly expanded. In the fields of precision measurement and quantum sensing, squeezed light, due to its unique noise distribution characteristics, has become a powerful tool for breaking the quantum noise limit in many optical measurement techniques. In the field of quantum information, squeezed-state light fields, due to the mutual correlation of noise in their orthogonal components, have become an important continuous variable quantum resource. Squeezed-state light sources are divided into two types: vacuum squeezed state and bright squeezed state. The vacuum squeezed state acts on a vacuum, while the bright squeezed state acts on a coherent state with a certain photon number. Therefore, bright squeezed state light sources have higher power than vacuum squeezed state light sources. Due to this characteristic of bright squeezed state light sources, their applications in certain fields are significantly different from those of vacuum squeezed state light sources. For example, in the field of quantum precision measurement, vacuum squeezed state light lacks coherent amplitude and is usually only used as auxiliary light injected into laser interferometers to improve the sensitivity of interferometric measurements. In contrast, bright squeezed state light has a certain coherent amplitude and can be used directly as signal light rather than auxiliary light in quantum precision measurement systems. In addition, the coherent superposition of two single-mode bright squeezed light fields can form a quantum entangled state, which is an important resource in various quantum technologies.

[0003] At present, the solutions for preparing bright compressed state light sources can be divided into two categories, one is the free-space solution and the other is the all-fiber solution. Among them, the most mature and most compressed solution is the free-space solution. In 2017, Shanxi University used periodically polarized potassium titanyl phosphate (PPKTP) to obtain a 12.6dB 1064nm bright compressed state output, which is the brightest compressed state light source reported to date. However, the structure of this type of compressed state light field generation system is complex and its anti-interference ability is poor, which makes it very sensitive to external environmental factors such as temperature, vibration and airflow, causing great trouble for the application expansion and industrialization of compressed state light sources. There is currently little research on bright compressed light sources based on all-fiber solutions. In patent CN202111558091, South China University of Technology proposed an all-fiber bright compressed state light source based on optical parametric down-conversion. The optical parametric down-conversion resonant cavity is composed of a grating, a phase modulator and a waveguide. The compression of the compressed light source is improved by improving the efficiency of nonlinear conversion. Compared with the free-space solution, the all-fiber solution has a simple system structure and does not require complex mode matching, which is conducive to the miniaturization and application promotion of compressed state light sources. However, the bright compressed state light source of the all-fiber solution is limited by the low nonlinear conversion efficiency, and the compression degree of the output light field is low.

[0004] Compared with the resonant cavity solution composed of a grating, a phase modulator, and a waveguide in patent CN202111558091, the resonant cavity structure of this solution is simpler and more efficient. The resonant cavity no longer contains a grating and a phase modulator, which reduces the loss of the resonant cavity and further improves the efficiency of nonlinear conversion. According to the formula for compression V(ω):

[0005]

[0006] Where γ is a parameter that characterizes the loss of the resonant cavity. It can be seen that the larger γ is, the greater the loss of the resonant cavity is, and the lower the compression of the theoretical output is. In the solution of CN202111558091, the locking of the resonant cavity and the signal light is achieved by dynamically adjusting the cavity length of the resonant cavity, so a phase modulator and a grating are required. In this solution, the locking of the resonant cavity and the signal light is achieved by controlling the wavelength of the tunable laser. Therefore, no other components are required in the cavity, which simplifies the resonant cavity device while further improving the nonlinear conversion efficiency of the resonant cavity and the compression of the theoretical compressed light source. Summary of the Invention

[0007] In order to solve the above technical problems, the present invention proposes an all-fiber structure with high compression and bright squeezed-state light source, comprising: a laser, an isolator, a first beam splitter, a frequency doubling medium, a second beam splitter, a first phase modulator, a second phase modulator, a circulator, a waveguide resonant cavity, a narrowband filter, a signal generator, a first servo control system, a second servo control system and a detector;

[0008] The laser light emitted by the laser enters the first beam splitter after passing through the isolator. A large proportion of the laser light after passing through the first beam splitter enters the frequency doubling medium to generate pump light; a small proportion of the laser light enters the second beam splitter.

[0009] The pump light generated by the frequency doubling medium enters the waveguide resonant cavity after passing through the second phase modulator;

[0010] The second beam splitter splits the light into two beams, one as background light and the other as signal light of a bright squeezed state light source. The signal light passes through the first phase modulator, then through a circulator and enters the waveguide resonant cavity. After being filtered by a narrowband filter, the bright squeezed state light signal is output.

[0011] The detector monitors the intensity of the optical signal returned by the waveguide resonator via the circulator in real time. The electrical signal generated by the detector is split into two: one electrical signal is input into the first servo control system to control the locking of the laser wavelength to the waveguide resonator; the other electrical signal is input into the first phase modulator through the second servo control system to achieve relative phase locking between the pump light and the signal light.

[0012] The first channel of the signal generator is connected to the first phase modulator and outputs a phase for modulating the signal light. The second channel and the third channel of the signal generator respectively output error signals required for demodulating the first servo control system and the second servo control system.

[0013] In a preferred embodiment, the waveguide material in the waveguide resonant cavity is lithium niobate crystal, and a film is coated on the incident end face of the lithium niobate crystal to achieve high reflection of signal light and high transmission of pump light, with the reflectivity of the signal light being greater than 99% and the transmittance of the pump light being greater than 95%; and a film is coated on the output end face of the lithium niobate crystal to achieve partial transmission of the signal light and high transmission of the pump light, with the transmittance of the signal light being 5%-20% and the transmittance of the pump light being greater than 95%.

[0014] In a preferred embodiment, the first servo control system demodulates the demodulated signal emitted by the signal generator and the electrical signal output by the detector to obtain a first error signal. The first error signal enters the control module of the first servo control system, and through the feedback algorithm, the signal required to control the laser wavelength is obtained. By controlling the tunable parameters of the laser, the wavelength is adjusted in real time to achieve locking of the laser wavelength and the waveguide resonant cavity.

[0015] In a preferred embodiment, the second servo control system demodulates the demodulated signal emitted by the signal generator and the electrical signal output by the detector to obtain a second error signal. The second error signal enters the control module of the second servo control system and, through a feedback algorithm, obtains a signal for controlling the phase of the pump light. The signal is input into the second phase modulator to adjust the phase of the pump light in real time, thereby achieving relative phase locking between the pump light and the signal light.

[0016] In a preferred embodiment, the frequency doubling medium is a periodically poled lithium niobate waveguide device.

[0017] In a preferred embodiment, the demodulated signal is a sinusoidal signal of the same frequency as the modulating signal.

[0018] In a preferred embodiment, the laser is a 1550 nm low-noise single-frequency tunable laser, the first phase modulator is a 1550 nm phase modulator, and the second phase modulator is a 775 nm phase modulator.

[0019] In a preferred embodiment, the first beam splitter is a 90 / 10 beam splitter and the second beam splitter is a 50 / 50 beam splitter.

[0020] In a preferred embodiment, polarization-maintaining optical fibers are used to transmit optical signals between optical devices.

[0021] Compared with the prior art, the present invention has the following beneficial technical effects:

[0022] The high-compression bright squeezed-state light source of the all-fiber structure of the present invention is based on the free-space standing wave resonant cavity design and proposes a preparation scheme for bright squeezed-state light signals based on the waveguide resonant cavity, thereby improving the nonlinear conversion efficiency and realizing the high-compression bright squeezed-state light source output of the all-fiber structure.

[0023] The system of the high-compression bright compressed-state light source with an all-fiber structure of the present invention is more compact as a whole, has strong resistance to environmental interference, is easy to combine with existing fiber optic systems, and can better promote the practical application process.

[0024] Compared with the all-fiber compressed light source solution based on four-wave mixing, the all-fiber structure of the present invention adopts an optical parametric down-conversion solution with higher nonlinear conversion efficiency, which can further improve the compression of the output light field. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 This is a schematic diagram of the structure of a high-compression bright compressed-state light source of the all-fiber structure of the present invention.

[0027] Figure 2 Schematic diagram comparing the waveguide resonant cavity of the present invention and the existing grating waveguide resonant cavity structure. DETAILED DESCRIPTION

[0028] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0029] like Figure 1 As shown in the figure, a schematic diagram of the structure of a high-compression bright squeezed-state light source of an all-fiber structure of the present invention is shown. The high-compression bright squeezed-state light source of the all-fiber structure includes: a laser, an isolator, a first beam splitter, a frequency doubling medium, a second beam splitter, a first phase modulator, a second phase modulator, a circulator, a waveguide resonant cavity, a narrowband filter, a signal generator, a first servo control system, a second servo control system and a detector.

[0030] like Figure 2 As shown, the design of the waveguide resonant cavity is the core of the present invention. It differs from traditional grating waveguide resonators and mirror waveguide resonators in that the present waveguide resonant cavity consists solely of a waveguide component, with laser resonance achieved through coatings applied to both ends of the waveguide crystal. The principle of external cavity enhancement indicates that the power within the resonant cavity is significantly increased. When the nonlinear crystal is fixed and phase-matched, the optical power density is positively correlated with the nonlinear conversion efficiency. Table 1 summarizes the differences in components and advantages between the present waveguide resonant cavity and traditional waveguide resonators.

[0031] The design of the waveguide resonant cavity of the present invention not only simplifies the overall structure of the waveguide resonant cavity, but also reduces the loss of the resonant cavity, thereby facilitating further improvement of the nonlinear conversion efficiency and thereby obtaining a compressed state light source with a higher degree of compression.

[0032] Table 1. Differences between a conventional waveguide resonant cavity and the waveguide resonant cavity of the present invention.

[0033]

[0034] Because the waveguide resonant cavity is achieved by coating the crystal at both ends, it is not easy to dynamically adjust the cavity length. Therefore, the first phase modulator, detector, signal generator, and first servo system form a first locking loop, which dynamically locks the wavelength of the laser to the waveguide resonant cavity by controlling the wavelength. The first phase modulator, second phase modulator, detector, signal generator, and second servo system form a second locking loop, which locks the relative phase difference between the signal light and the pump light.

[0035] In a preferred embodiment, the laser is a low-noise single-frequency tunable laser that outputs linearly polarized laser light. The laser can be a single-frequency fiber laser or a single-frequency semiconductor laser.

[0036] The isolator is a fiber optic isolator corresponding to the laser wavelength, which is used to prevent the return light from returning to the laser and causing damage to the laser or interference to the entire system.

[0037] The first beam splitter is a proportional beam splitter corresponding to the laser wavelength, for example, a 90 / 10 beam splitter is used to split the fundamental frequency laser into two paths, one path (large proportional part) is used for frequency doubling to generate pump light, and the other path (small proportional part) is used for seed light generated by bright compressed light and background light required for detection.

[0038] The frequency doubling medium can be an optical fiber medium, an optical fiber coupled medium, a frequency doubling medium or a periodically poled frequency doubling medium. The higher the second-order nonlinear coefficient of the frequency doubling medium, the higher the pump light generated by the frequency doubling, or the lower the fundamental frequency light power required to obtain the same pump light power.

[0039] The second beam splitter is a proportional beam splitter corresponding to the laser wavelength, such as a 50 / 50 beam splitter, and its purpose is to split the fundamental frequency laser into two paths, one for the signal light generated by the bright compressed light, and the other for the background light required for detection.

[0040] It should be noted that the measurement of compressed state light sources uses the balanced zero-beat detection principle, which requires two beams of light. The compression degree of the compressed state light source is measured through the interference of the two beams of light. In addition to the compressed light to be measured, the other beam separated from the original laser is called background light.

[0041] The first phase modulator is an optical fiber phase modulator capable of modulating the phase of the system laser, and is used to modulate the laser phase to have a fixed frequency.

[0042] The second phase modulator is a fiber phase modulator that can modulate the phase of the system's frequency-doubled laser and is used to modulate the phase of the pump light and lock the relative phase difference between the pump light and the signal light.

[0043] The circulator is a circulator corresponding to the system laser wavelength. The signal light is input from the first port 1 of the circulator and output from the second port 2. The light returned from the waveguide resonant cavity is input from the second port 2 and output from the third port 3.

[0044] The waveguide material of the waveguide resonant cavity is a periodically polarized optical parametric down-conversion medium with high nonlinear conversion efficiency, such as PPLN. During the preparation of a compressed state light source, the nonlinear conversion efficiency directly affects the theoretical degree of compression of the compressed state light source generated by the nonlinear process. Therefore, in free-space solutions, it is preferred to use a resonant cavity structure to improve the efficiency of nonlinear conversion.

[0045] This solution is also applicable to all-fiber structures, and the present invention innovatively proposes that a waveguide resonant cavity can be realized by directly coating a waveguide crystal. The incident end face of the waveguide crystal is coated with a film that achieves high reflection for signal light and high transmission for pump light, with a reflectivity of >99% for signal light and a transmittance of >95% for pump light; the output end face is coated with a film that achieves partial transmission for signal light and high transmission for pump light, preferably, a transmittance of 5%-20% for partial transmission for signal light and a transmittance of >95% for pump light.

[0046] The narrowband filter is an optical fiber narrowband filter corresponding to the wavelength of the system pump light and signal light, and is used to filter out the pump light so that only the signal light, that is, the compressed light, is output.

[0047] Compared with the resonant cavity solution composed of grating, phase modulator and waveguide in the prior art, the resonant cavity structure of this solution is simpler and more efficient. The resonant cavity no longer contains grating and phase modulator, which reduces the loss of the resonant cavity and further improves the efficiency of nonlinear conversion.

[0048] In this scheme, the locking of the resonant cavity and the signal light is achieved by controlling the wavelength of the tunable laser. Therefore, no other components are required in the cavity. This simplifies the resonant cavity device and further improves the nonlinear conversion efficiency of the resonant cavity and the compression degree of the theoretical compressed light source.

[0049] The first channel of the signal generator is connected to the first phase modulator and outputs a phase for modulating the signal light. The second channel and the third channel of the signal generator respectively output error signals required for demodulating the first servo control system and the second servo control system.

[0050] The signal generator outputs the modulation and demodulation signals required by the system for loop-locked operation. The modulation signal is typically a sinusoidal signal of several tens of MHz, such as 30 MHz, with an amplitude adjustable based on the specifications of the phase modulator. The demodulation signal is a sinusoidal signal of the same frequency as the modulation signal.

[0051] The first servo control system demodulates the demodulated signal from the signal generator and the light intensity signal from the detector to generate a first error signal. This error signal enters the control module of the first servo control system and, through a feedback algorithm such as a proportional-integral-differential algorithm, generates the current or voltage signal required to control the laser wavelength. This signal controls the tunable parameters of the tunable laser to adjust the wavelength in real time, achieving dynamic matching with the waveguide resonant cavity and locking the laser wavelength to the waveguide resonant cavity.

[0052] The second servo control system demodulates the demodulated signal from the signal generator and the light intensity signal from the detector to generate a second error signal. This second error signal enters the servo system's control module and, through a feedback algorithm such as the proportional-integral-differential algorithm, generates a voltage signal to control the pump light phase. This signal is input into the second phase modulator to adjust the pump light phase in real time, achieving relative phase lock between the pump light and the signal light.

[0053] Preferably, the optical fibers are polarization-maintaining fibers. Figure 1 The black line in the middle represents the optical path, that is, the optical fiber, the arrow indicates the direction of light transmission, and the blue line represents the circuit.

[0054] In a preferred embodiment, the high-compression bright squeezed-state light source structure of the all-fiber structure includes a 1550nm low-noise single-frequency tunable laser, a 1550nm isolator, a 1550nm 90 / 10 first beam splitter 1, a frequency doubling medium, a 1550nm 50 / 50 second beam splitter 2, a 1550nm phase modulator, a 775nm phase modulator, a 1550nm circulator, a waveguide resonant cavity, a 1550nm narrowband filter, a signal generator, a first servo control system, a second servo control system and a 1550nm detector.

[0055] A 1550nm low-noise, single-frequency tunable laser beam passes through a 1550nm isolator and then into a 1550nm 90 / 10 beam splitter. The isolator prevents light reflected from subsequent components from entering the laser and affecting its stability. After passing through the 1550nm 90 / 10 beam splitter, most of the 1550nm laser beam enters the frequency-doubling medium, generating 775nm pump light.

[0056] The frequency-doubling medium is a periodically poled lithium niobate (PPLN) waveguide. Pump light passes through a 775nm phase modulator and enters the waveguide resonator. A small portion of the 1550nm laser beam enters a 1550nm 50 / 50 beam splitter, with one channel serving as background light for subsequent detection and the other as signal light for a bright squeezed-state source. The signal light then passes through a 1550nm phase modulator and enters the waveguide resonator.

[0057] The signal generator has multi-channel synchronous output. The first channel 1 outputs a sine wave with a frequency of 10 MHz for modulating the phase of the signal light. The second channel 2 and the third channel 3 also output sine waves with a frequency of 10 MHz for demodulating the error signals required by the first servo control system and the second servo control system.

[0058] The waveguide material in the waveguide resonant cavity is PPLN crystal, and the incident end face of the PPLN crystal is coated with a film that achieves high reflection for signal light and high transmission for pump light, with a reflectivity of signal light greater than 99% and a transmittance of pump light greater than 95%; the output end face is coated with a film that achieves partial transmission for signal light and high transmission for pump light, preferably, the transmittance of partial transmission for signal light is 10% and the transmittance for pump light is greater than 95%.

[0059] The signal light reflected by the waveguide resonant cavity is input through the second port 2 of the circulator and output through the third port 3.

[0060] The detector monitors the intensity of the reflected light in real time, and the generated electrical signal is split into two parts. One part is input into the first servo control system 1, and the demodulation feedback is used to control the wavelength of the laser and lock it to the waveguide resonant cavity; the other part is input into the second servo control system 2, and the demodulation feedback is input into the 775nn phase modulator (pump light phase modulator) to achieve relative phase locking between the pump light and the signal light.

[0061] At this time, the output light of the waveguide resonant cavity contains the remaining 775nm pump light and the 1550nm bright compressed light. The remaining 775nm pump light can be filtered out by a 1550nm narrowband filter to achieve the output of the final 1550nm bright compressed state light source.

[0062] This invention uses an all-fiber solution, based on a waveguide resonant cavity, to achieve the output of a bright, highly compressed squeezed-state light source. Drawing on the design of a free-space standing-wave resonant cavity, this method proposes a bright squeezed-state preparation method based on a waveguide resonant cavity, improving nonlinear conversion efficiency and achieving high-compression, bright squeezed-state light output through an all-fiber solution.

[0063] Compared with mainstream free-space solutions, the present invention avoids complex problems such as pattern matching and mode locking. It has a compact structure, strong resistance to environmental interference, and is better compatible with back-end application systems, accelerating the practical application of compressed light fields.

[0064] Compared with the all-fiber compressed light source solution based on four-wave mixing, the present invention adopts an optical parametric down-conversion solution with higher nonlinear conversion efficiency, which can further improve the compression degree of the output light field.

[0065] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted via the computer-readable storage medium. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or a data center that includes one or more available media integrations. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state drive (SSD)).

[0066] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present application, and such modifications or substitutions should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. An all-fiber structured, high-compression, bright, compressed-state light source, characterized in that: include: A laser, an isolator, a first beam splitter, a frequency doubling medium, a second beam splitter, a first phase modulator, a second phase modulator, a circulator, a waveguide resonator, a narrowband filter, a signal generator, a first servo control system, a second servo control system, and a detector; The laser light emitted by the laser enters the first beam splitter after passing through the isolator. A large proportion of the laser light after passing through the first beam splitter enters the frequency doubling medium to generate pump light; a small proportion of the laser light enters the second beam splitter. The pump light generated by the frequency doubling medium enters the waveguide resonant cavity after passing through the second phase modulator; The second beam splitter splits the light into two beams, one as background light and the other as signal light of a bright squeezed state light source. The signal light passes through the first phase modulator, then through a circulator and enters the waveguide resonant cavity. After being filtered by a narrowband filter, the bright squeezed state light signal is output. The detector monitors the intensity of the optical signal returned by the waveguide resonator via the circulator in real time. The electrical signal generated by the detector is split into two: one electrical signal is input into the first servo control system to control the locking of the laser wavelength to the waveguide resonator; the other electrical signal is input into the first phase modulator through the second servo control system to achieve relative phase locking between the pump light and the signal light. The first channel of the signal generator is connected to the first phase modulator and outputs a phase for modulating the signal light. The second channel and the third channel of the signal generator respectively output error signals required for demodulating the first servo control system and the second servo control system.

2. The all-fiber structured high-compression bright compressed-state light source according to claim 1, characterized in that: The waveguide material in the waveguide resonant cavity is lithium niobate crystal. The incident end face of the lithium niobate crystal is coated with a film that achieves high reflection for signal light and high transmission for pump light, with a reflectivity of >99% for signal light and a transmittance of >95% for pump light. The output end face of the lithium niobate crystal is coated with a film that achieves partial transmission for signal light and high transmission for pump light, with a transmittance of 5%-20% for signal light and a transmittance of >95% for pump light.

3. The all-fiber structured high-compression bright compressed-state light source according to claim 1, characterized in that: The first servo control system demodulates the demodulation signal emitted by the signal generator and the electrical signal output by the detector to obtain a first error signal. The first error signal enters the control module of the first servo control system and obtains the signal required to control the laser wavelength through a feedback algorithm. The wavelength is adjusted in real time by controlling the tunable parameters of the laser to achieve locking of the laser wavelength and the waveguide resonant cavity.

4. The all-fiber structured high-compression bright compressed-state light source according to claim 1, characterized in that: The second servo control system demodulates the demodulated signal emitted by the signal generator and the electrical signal output by the detector to obtain a second error signal. The second error signal enters the control module of the second servo control system and obtains a signal for controlling the phase of the pump light through a feedback algorithm. The signal is input into the second phase modulator to adjust the phase of the pump light in real time, thereby achieving relative phase locking between the pump light and the signal light.

5. The all-fiber structured high-compression bright compressed-state light source according to claim 1, characterized in that: The frequency doubling medium is a periodically poled lithium niobate waveguide device.

6. The all-fiber structured high-compression bright compressed-state light source according to claim 3, characterized in that: The demodulated signal is a sinusoidal signal with the same frequency as the modulating signal.

7. The all-fiber structured high-compression bright compressed-state light source according to claim 1, characterized in that: The laser is a 1550nm low-noise single-frequency tunable laser, the first phase modulator is a 1550nm phase modulator, and the second phase modulator is a 775nm phase modulator.

8. The all-fiber structured high-compression bright compressed-state light source according to claim 1, characterized in that: The first beam splitter is a 90 / 10 beam splitter, and the second beam splitter is a 50 / 50 beam splitter.

9. The all-fiber structured high-compression bright compressed-state light source according to claim 1, characterized in that: Polarization-maintaining optical fiber is used to transmit optical signals between optical devices.

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