262 results about "Saturable absorption" patented technology

The invention belongs to the technical field of photoelectronics, and particularly relates to a wide-spectrum narrow-linewidth semiconductor mode-locked laser, and the collaboration of a saturable absorption region SA and a resonator is reflected in time domain-frequency domain dual optimization. And the resonator optimizes the frequency domain characteristics through nonlinear broadening, phase synchronization and mode purification. The SA adjusts a mode locking threshold value in real time through dynamic bias voltage, the pulse energy stability is ensured, dispersion management of the resonator balances the SPM and group velocity dispersion, spectrum splitting is avoided, and the dissipative soliton form is maintained. Besides, due to heterogeneous integration of the InP-based SA and the SiN-based resonator, wafer bonding of the InP-based SA and the SiN-based resonator is realized, high-efficiency energy transfer is realized through the low-loss conical waveguide, a high-performance frequency comb with a wide spectrum and a narrow pulse width is output, and the high-performance frequency comb can be widely applied to the fields of ultrafast optics, coherent light communication and precision spectroscopy.

The invention discloses a high-tolerance synchronous dual-band pulse laser, and relates to the field of lasers, and the laser comprises a first resonant cavity and a second resonant cavity; the first resonant cavity comprises a first pumping source and an optical annular cavity formed by sequentially connecting a first wavelength division multiplexer, a first thulium-doped optical fiber, a first optical coupler, a first isolator, a second wavelength division multiplexer, a high-nonlinearity saturable absorber, a third wavelength division multiplexer and a first polarization controller; the second resonant cavity comprises a second pumping source and an optical annular cavity which is formed by sequentially connecting a fifth wavelength division multiplexer, a second erbium-doped fiber, a second optical coupler, a second wavelength division multiplexer, a high-nonlinearity saturable absorber, a third wavelength division multiplexer, an electric control adjustable delay line, a fourth wavelength division multiplexer, a second polarization controller and a second isolator, and the fifth wavelength division multiplexer, the second erbium-doped fiber, the second optical coupler, the high-nonlinearity saturable absorber, the third wavelength division multiplexer, the electric control adjustable delay line, the fourth wavelength division multiplexer, the second polarization controller and the second isolator; and the first optical coupler and the second optical coupler respectively output synchronization pulses in the wave bands of 2 microns and 1.5 microns. The device is compact in structure, low in manufacturing cost, convenient to operate and capable of covering the mid-infrared band of 2 microns.

Disclosed in the present invention is a near-infrared wavelength scanning pulse fiber laser having a low mode-locking threshold. According to the present invention, a nonlinear amplifying loop mirror and a saturable absorber mirror architecture are used to achieve a low mode-locking threshold and ensure long-term mode-locking stability. After mode-locking self-starting, an automatic control module automatically achieves single-pulse operation by adjusting the intensity of retro-reflected pulses. In the single-pulse operation stage, different frequencies of radio frequency signals and different signal intensities are provided for an acousto-optic tunable filter by means of a radio frequency module to achieve a 1030 nm-1100 nm wavelength scanning and tuning range.

The invention relates to a self-calibration atomic wavelength meter. The self-calibration atomic wavelength meter comprises a saturated absorption spectrum light path for locking a detection laser frequency on a cesium atom energy level transition line based on a saturated absorption spectrum; the double-peak spectrum light path scans the frequency of a coupled laser after the frequency of the detection laser is locked by a saturated absorption spectrum, and when the detection laser and the coupled laser jointly act on alkali metal atoms and are subjected to resonance excitation, an electromagnetic induced transparency effect is generated; when the detection laser is detuned, the detection laser and the combined laser jointly act on the alkali metal atoms to generate non-resonance excitation, a double-peak EIT spectrum with Doppler frequency shift is generated, and the wavelength measurement of the current detection laser can be completed based on the linear relation between the double-peak spectrum interval and the detuning amount of the detection laser. In addition, the double-peak spectrum interval is compared with the atomic energy level transition frequency, the difference between the double-peak spectrum interval and the atomic energy level transition frequency serves as an error signal to be fed back to the control end of the detection laser, the frequency of the detection laser is tuned to the reference frequency standard, and calibration of the wavemeter can be achieved.

The invention relates to the technical field of semiconductor lasers, in particular to a semiconductor laser with an adjustable time domain. According to the time-domain-adjustable semiconductor laser, a mutual injection coupling region and a gain region are arranged on a semiconductor laser chip, the mutual injection coupling region comprises multiple sections of interval units, and the ratio of the length of a saturable absorber region to the length of the gain region in a resonant cavity is controlled by adjusting the absorption / gain characteristics of the interval units. And a plurality of pulse generation mechanisms are switched to adjust the pulse width. On the premise that the structural complexity of the semiconductor laser is reduced, large-range adjustment of laser pulses can be achieved.

The invention discloses a plug-and-play Rydberg atom preparation device based on a three-photon absorption method, which comprises a laser generator, a laser input module, a laser detector, three frequency stabilization modules and a temperature and humidity control module, and is characterized in that the laser generator is used for preparing laser to be measured; the input module is used for transmitting and introducing laser; the saturated absorption frequency stabilization module, the electromagnetic induction transparent frequency stabilization module and the heating electromagnetic induction transparent frequency stabilization module all adopt a glass bonding technology to build frequency stabilization light paths; the laser detection device is used for detecting laser lines in the saturation absorption frequency stabilization module, the electromagnetic induction transparent frequency stabilization module and the heating electromagnetic induction transparent frequency stabilization module and locking the laser frequency corresponding to the specific wavelength. According to the invention, a frequency-stabilized light path is built by using a glass bonding technology, so that devices and the size are greatly reduced, and the integration level of a light path system is greatly improved; moreover, the degree of freedom of device adjustment can be reduced, and the reliability and stability of a laser frequency stabilization optical path are effectively improved.

The invention belongs to the technical field of quantum precision measurement, and particularly discloses a frequency stabilization system and a frequency stabilization method for an external cavity semiconductor laser. The system comprises a saturated absorption spectrum module, a wavelet peak searching module, a modulation and demodulation module, a bias amplification module and a switch module, wherein the saturated absorption spectrum module outputs an electric signal of a saturated absorption spectrum; under the control of the frequency locking instruction, the wavelet peak searching module outputs a target bias voltage signal corresponding to the locking frequency based on the electric signal; the modulation and demodulation module performs signal modulation and demodulation based on the electric signal and a reference signal corresponding to the locking frequency to output a modulation signal and a demodulation signal; and the bias amplification module performs superposition and amplification processing on the modulation signal, the demodulation signal and the target bias voltage signal, and outputs a target superposition signal to a PZT modulation port of the laser, so that the output laser freely operates on the locking frequency. According to the invention, the laser is not liable to generate mode hopping in the frequency locking process, the whole frequency stabilization system is more stable, the structure is simple, and the cost is low.

The invention discloses an automatic frequency stabilization system based on dual-core correlation matching intelligent peak searching. The automatic frequency stabilization system comprises the following steps that S1, a saturated absorption spectrum light path and a circuit are built, debugged and optimized; s2, constructing a double-matching template; s3, triangular wave voltage scanning and clock timing are started, and signals are collected and transmitted; s4, starting a KCF algorithm, applying a template to track model matching, judging a result obtained by matching, finding a peak point and solving a corresponding scanning voltage; and S5, recording a peak point scanning voltage, closing a scanning signal, starting sinusoidal signal modulation, and giving a triangular wave scanning voltage corresponding to a peak value to the sinusoidal signal as an offset. The spectrum line peak value suspected area can be effectively positioned, the double-branch and correlation filtering tracking method can perform precise secondary searching in the suspected area, the locking precision is greatly improved, the long-term stability of 10-12 orders of magnitude is ensured, and meanwhile the good vibration interference resistance can be achieved when a vibration signal occurs.

The invention discloses an all-fiber structure pulse laser based on a superfine single-crystal fiber and a preparation method thereof. The all-fiber structure pulse laser comprises a gain single-crystal fiber and a pulse modulation single-crystal fiber, and the gain single-crystal fiber and the pulse modulation single-crystal fiber form a superfine single-crystal fiber heterogeneous bonding structure through thermocompression bonding; the gain single-crystal optical fiber serves as a laser gain medium, the pulse modulation single-crystal optical fiber serves as a saturable absorber, the gain single-crystal optical fiber is provided with a high-reflection grating, the high-reflection grating and an oblique-angle low-reflection end arranged at the tail end of the pulse modulation single-crystal optical fiber form a resonant cavity, and pump light is input into the gain single-crystal optical fiber and enters the resonant cavity through the high-reflection grating. And the oblique-angle low-reflection end outputs pulse laser. The gain section and the modulation section are fused into an integrated structure through the superfine single crystal optical fiber bonding technology, the high-reflection grating is inscribed through the femtosecond laser direct writing technology, low-reflection-mirror oblique angle processing is carried out at the output end, space coupling loss is eliminated, and all-optical-fiber monolithic integration is achieved.

The invention discloses a dual-wavelength mode-locked laser generating device and a dual-wavelength mode-locked laser generating method, and belongs to the technical field of optical communication, and the dual-wavelength mode-locked laser generating device comprises a pumping source, an optical integration module, a gain optical fiber, a saturable absorber and a dual-wavelength pulse independent polarization mode linear coupling regulation and control structure, linear coupling strength of cross-polarization components in two wavelength pulses is independently regulated and controlled by using a structure of a polarization controller and a polarization maintaining optical fiber, and dual-wavelength mode-locked pulse laser of different types of pulse combinations can be obtained. The coherent pulse light source with unique spectral characteristics can provide a low-cost light source for the fields of high repetition frequency optical combs, all-fiber architecture high repetition frequency soliton sequences and microwave photonics.

The invention provides a gas saturation absorption optical path structure based on dual optical path enhancement, which belongs to the field of laser optical path design and comprises an optical fiber circulator, a gas absorption chamber and an optical fiber reflector. A first port of the optical fiber circulator is connected with a laser output optical fiber, a second port of the optical fiber circulator is connected with an input collimator of the gas absorption chamber, and a third port of the optical fiber circulator is connected with a detector and is used for providing frequency reference for gas absorption; and the optical fiber reflector is connected with the output end of the gas absorption chamber. According to the invention, the physical contradiction between the air chamber size and the optical path gain is broken through, and a compact frequency stabilization system with miniaturization and high stability is realized.

The invention discloses a narrow-linewidth thulium-doped fiber laser oscillator, which is characterized in that a saturable absorption fiber has certain absorption on signal light wavelength and is arranged between a first high-reflectivity fiber bragg grating and a second high-reflectivity fiber bragg grating, and when the laser gain exceeds the loss of a laser resonant cavity formed by the first high-reflectivity fiber bragg grating, the second high-reflectivity fiber bragg grating and a low-reflectivity fiber bragg grating, a thulium-doped fiber is generated; laser oscillation is formed and output through the low-reflection fiber bragg grating; the first and second high-reflectivity fiber gratings form an etalon effect; an etalon effect is formed between the second high-reflectivity fiber bragg grating and the low-reflectivity fiber bragg grating and between the first high-reflectivity fiber bragg grating and the low-reflectivity fiber bragg grating; signal light oscillated between the first high-reflectivity fiber bragg grating and the second high-reflectivity fiber bragg grating can form standing waves, and a dynamic grating is formed in the saturable absorption fiber. Under the action of the resonant cavity vernier effect and the saturable absorption dynamic optical fiber, signal light oscillates in a narrow linewidth mode between the first high-reflectivity fiber bragg grating and the second high-reflectivity fiber bragg grating, and the narrowed signal light is injected into the thulium-doped gain optical fiber through the second high-reflectivity fiber bragg grating, so that the laser maintains narrow spectral linewidth operation.

The invention relates to a nanosecond fiber laser and method for high-order chaotic pulses. A fiber ring cavity of the laser comprises a wavelength division multiplexer, an erbium-doped fiber, a first polarization controller, an analyzer, a second polarization controller, an output coupler, a dispersion control unit, a fiber isolator and a band-pass filter which are connected in sequence. The method comprises the steps that pumping continuous light is coupled into the laser through the wavelength division multiplexer; pumping continuous light is absorbed by using an erbium-doped optical fiber and is stimulated to radiate a long-wave-band gain pulse; under the combined action of the first polarization controller, the polarization analyzer and the second polarization controller, an equivalent saturable absorption effect is generated by utilizing nonlinear polarization rotation generated when gain pulses are propagated in an optical fiber, and large anomalous dispersion is introduced to realize generation of nanosecond pulses; through the band-pass filter, nanosecond pulses are allowed to be generated, and meanwhile, the nonlinear increasing speed of propagation and accumulation of the nanosecond pulses in the cavity is controlled, so that order-by-order generation of high-order chaotic pulses is realized. According to the invention, reliable output of high-order chaotic pulses can be realized.

The invention discloses a reflective pumping detection nondestructive testing device and method capable of saturatively absorbing uniformity in a mirror surface. The device is based on a wavelength degeneracy pumping-detection principle, and comprises a femtosecond laser source, a beam splitter, an optical delay line, a double-frequency optical chopper, a two-dimensional precision translation stage, a coaxial focusing system, a spatial filtering diaphragm arranged in a reflection light path, a photoelectric detector, a lock-in amplifier and a signal processing unit. According to the method, different point positions of a sample are accurately positioned through a two-dimensional translation stage, a nonlinear differential reflectance dynamic curve of each point is measured under low power, the maximum differential reflectance and the carrier lifetime are extracted as characteristic parameters, the spatial relative standard deviation of the characteristic parameters is calculated, and lossless and quantitative in-plane uniformity evaluation is realized. According to the method, the interference of the pump light is effectively filtered through the space filtering diaphragm, the signal-to-noise ratio is remarkably improved in combination with the phase-locked amplification technology, and the problem that the nonlinear optical performance uniformity of the saturable absorber mirror cannot be quantitatively evaluated through a traditional method is solved.

A passively, Q-switched laser is described. The laser may operate at an eye-safe lasing wavelength of 1.34 microns and use a gain element of Nd:YVO4 and a saturable absorber element of V:YAG with a space separating the gain element and saturable absorber element. The Q-switched laser is pumped by a grating stabilized laser diode. The laser may be used in laser ranging applications.

Apparatus, systems, and methods for a bidirectional mode-locked all-polarization maintaining fiber laser with two counter-propagating, orthogonally polarized pulses are applicable in a variety of applications. A mode-locked fiber laser can be realized with a laser cavity including a first polarization maintaining gain fiber, a second polarization maintaining gain fiber, and a saturable absorber. The saturable absorber can be arranged with the first polarization maintaining gain fiber and the second polarization maintaining gain fiber to generate two counter-propagating pulses, being orthogonally polarized with respect to each other. The laser cavity can include a circulator arranged to provide separate paths for the two counter-propagating pulses in a portion of the fiber laser cavity.

A ring resonator (10) and a NALM (20) configured as a saturable absorption mechanism constitute a laser oscillator. A multiport BPF (12) is provided to a path through which light propagates in the laser oscillator, the multiport BPF (12) passing light in a prescribed band of the propagating light, and branching light outside of the prescribed band as monitoring light (L). A photodetector (1) detects the monitoring light (L). A control unit (2) controls the oscillation state of the light propagating through the laser oscillator on the basis of the intensity of the monitoring light (L), thereby controlling the mode synchronization of the light propagating through the laser oscillator.

The invention discloses a mode-locked laser based on cross-polarization feedback injection and a control method thereof, and belongs to the technical field of lasers, a light beam emitted by a VCSEL laser is divided into two beams through an optical splitter, the first beam is divided into a first TM mode light beam and a first TE mode light beam through a first polarization-maintaining beam splitter, the two beams form an annular loop on a light path, and the first TM mode light beam and the first TE mode light beam form an annular loop on the light path; and a half-wave plate is arranged on the loop. And the two beams of light are respectively and oppositely propagated along the annular loop, return to the VCSEL laser after being subjected to polarization state conversion by the half-wave plate, are reflected by a resonant cavity of the VCSEL laser again, are coupled into the resonant cavity after being subjected to secondary polarization state conversion by the half-wave plate, and finally finish the output of the mode-locked laser. The laser reaches a mode-locked state by adjusting the angle of the half-wave plate. The laser uses an orthogonal polarization feedback injection mechanism, does not need to use a saturable absorber and a polarization inverter, is simple in structure and easy to implement, greatly reduces the cost and complexity of a system, and meets the requirements of different application scenes.

A self-calibration atomic wavemeter, including a saturated absorption spectrum optical path based on saturated absorption spectrum to lock the probe laser frequency on cesium atomic energy level transition line; a double-peak spectrum optical path scans the coupling laser frequency after the probe laser frequency is locked by the saturated absorption spectrum, when the probe laser and the coupling laser jointly act on the alkali metal atom and resonantly excite, the electromagnetic induced transparency effect is generated; and when the probe laser is detuned, the probe laser and the coupling laser jointly act on the alkali metal atom to produce non-resonant excitation, and the double-peak EIT spectrum with Doppler frequency shift is generated, based on the linear relationship between the double-peak spectrum interval and the probe laser detuning amount, the wavelength measurement of the current probe laser can be completed, in addition, the double-peak spectrum interval and the atomic energy level transition frequency are compared, and the difference between the two is taken as an error signal feedback to the control end of the probe laser, and the frequency of the probe laser is tuned to the reference frequency benchmark, so that the calibration of the wavemeter can be realized.

This invention discloses a passively mode-locked fiber laser with switchable transverse modes and an optical communication system, relating to the field of ultrafast optical technology. The passively mode-locked fiber laser comprises a pump source and a laser resonator. The laser resonator comprises a wavelength division multiplexer, a gain fiber, a few-mode isolator, a first polarization controller, a saturable absorber, a second polarization controller, a mode-selective photon lantern, and a few-mode coupler, all connected in sequence along the direction of light propagation. Compared to existing technologies, the present invention offers low insertion loss and high spatial mode selection flexibility, making it widely applicable in communications, industrial processing, detection, and other fields.

The present invention provides a light-emitting device that improves the peak value of the light pulses used for irradiation. [Solution] The light-emitting device has a spacer portion that includes a saturable absorption layer provided between a first electrode, which is a back electrode, and a resonator portion. The spacer portion has a first spacer layer provided on the first side with respect to the saturable absorption layer, and a second spacer layer provided on the second side with respect to the saturable absorption layer. The first spacer layer and the second spacer layer are of a first conductivity type.

The invention provides a continuous variable quantum key modulation system and an optical waveguide unit preparation method, and belongs to the field of quantum communication, the continuous variable quantum key modulation system comprises an integrated amplitude modulation module and a modulation control module, the integrated amplitude modulation module comprises an optical waveguide unit of an integrated Mxene film layer, a modulation light input unit and a signal light coupling unit; the modulation control module receives the modulation instruction and transmits a modulation parameter corresponding to the modulation instruction to the integrated amplitude modulation module; the modulated light input unit receives modulated light, and excites the saturation absorptivity of the Mxene film layer according to the input light power; the signal light coupling unit receives the signal light and couples the signal light and the modulated light to the optical waveguide unit; and the optical waveguide unit is used for performing all-optical amplitude modulation on the modulated light and the signal light based on the modulation frequency to obtain a modulated optical signal after the saturated absorptivity of the Mxene film layer is excited. As the system can stably output ideal pulse light, the problem of information leakage caused by imperfect light pulse is avoided.

This invention discloses a wavelength-tunable dual-cavity ultrafast fiber laser based on rotating optical fibers and its control method, relating to the field of laser technology. The dual-cavity ultrafast fiber laser of this invention integrates a wavelength division multiplexer within a dual-ring resonant cavity, structurally integrating two wavelength channels, each containing an independent gain fiber, to achieve dual-color soliton output and reduce gain competition. By setting an adjustable rotating fiber filter, consisting of a polarization controller, rotating optical fibers, and a polarization-dependent isolator, in the multiplexing section, the center wavelength of both wavelengths is tunable. Simultaneously, the two sub-cavities share the same saturable absorber to achieve passive synchronous mode-locking, and a delay line is introduced into one of the channels to adjust the equivalent cavity length, achieving repetition frequency matching and timing alignment between the two sub-cavities, thereby obtaining stable, tunable, and synchronous dual-wavelength ultrashort pulse output.

The invention provides a portable mid-infrared pulse fiber laser, a working method and a laser system thereof. The portable mid-infrared pulse fiber laser comprises a pumping source, a first convex lens, a dichroic mirror, a second convex lens, a rare earth ion doped fiber, a third convex lens, a fourth convex lens, a vanadium dioxide saturable absorber, a semiconductor heating sheet, a direct current power supply and a wire which are sequentially arranged along an optical axis. According to the working method, the temperature of the vanadium dioxide saturable absorber is controlled by starting electric control of the semiconductor heating sheet and adjusting the control voltage of the direct-current power supply; when the temperature reaches heat balance, a pumping source is started; the power of the pumping source is increased until the power threshold of the passive Q-switched pumping light is reached, and the dichroscope outputs mid-infrared passive Q-switched pulse laser. The laser system comprises the laser and a control circuit. Under the condition of low pumping power, high-peak-power, high-pulse-energy and nanosecond-level narrow-pulse-width mid-infrared passive Q-switched pulse fiber laser output is achieved; and the portability and the practicability of the laser are improved due to the portability and long-endurance design.

A pulsed laser device including: a III-V-on-silicon type hybrid pulsed laser source, including a gain section and a saturable absorber section which rest on a photonic substrate, and a longitudinal waveguide located in the photonic substrate; a control optical device including an optical pulse emitter source and a lateral waveguide located in the photonic substrate; the waveguides being sized so that the confinement factor Γlae / SA, Γlai / G in the quantum wells of the corresponding section of the optical mode of the lateral waveguide is higher than the confinement factor IL / ms, in the quantum wells of the semiconductor medium, of the optical mode of the longitudinal waveguide.

The present invention discloses a watt-class linear cavity single-frequency fiber oscillator based on dynamic refractive index grating regulation. The oscillator comprises two sections of active optical fiber, which are pumped by two pump sources respectively. The two sections of active optical fiber fully absorb the pump power while still retaining unpumped portions. The standing wave effect in the linear cavity laser generates narrowband refractive index modulation gratings in the unpumped portions of the two sections of active optical fiber. Therefore, the two sections of active optical fiber serve as gain media to provide laser gain and as saturable absorbers to produce a frequency selection effect. The narrowband refractive index modulation gratings in the two sections of active optical fiber form a vernier effect, which enhances frequency selection and ensures that the power output level of the single-frequency fiber oscillator reaches the watt level.

The application provides a saturable absorption device, a preparation method and a low-threshold starting pulse mode-locked laser, and relates to the technical field of lasers. The application discloses a method for preparing a high-quality bismuth copper selenium oxide single crystal by a chemical vapor transport method, and a saturable absorption device prepared by simply using the high-quality bismuth copper selenium oxide single crystal can be applied to a pulse mode-locked laser, and can generate super-short pulse laser output, has high stability and a high signal-to-noise ratio, and has a low starting threshold.

This invention provides a semiconductor mode-locked laser and its fabrication method, relating to the field of optoelectronics. It addresses the problem in existing technologies where femtosecond pulses are difficult to output due to self-phase modulation and dispersion effects, thereby avoiding the use of external pulse compression technology and reducing production costs. The semiconductor mode-locked laser includes a mirror region, a gain region, and a saturable absorption region. The gain region is located between the mirror region and the saturable absorption region and is connected to both regions. The semiconductor mode-locked laser also includes a substrate, and a chirped grating layer and an active layer disposed on the same side of the substrate. The chirped grating layer is located in the mirror region and includes multiple gratings with a grating period linearly decreasing along the emission direction of the semiconductor mode-locked laser. The active layer is located in the gain region and the saturable absorption region, and the distance between the chirped grating layer and the substrate is greater than the distance between the active layer and the substrate.

The application discloses an interference filter type multi-wavelength erbium-doped fiber laser based on optical path difference regulation, relates to the technical field of a ring-shaped tunable multi-wavelength erbium-doped fiber laser, and comprises a pump source, a wavelength division multiplexer, an erbium-doped fiber, an isolator, a first optical fiber coupler, a three-paddle polarization controller, a polarizer, a Mach-Zehnder interferometer filter containing an adjustable delay line, a black phosphorus saturable absorber and an extrusion type polarization controller which constitute a ring cavity. By connecting a 0-6.6 cm continuous adjustable delay line to one arm, the optical path difference of the filter two arms is accurately regulated, and continuous precise tuning of wavelength spacing of 0.3 nm to 1.54 nm is realized; meanwhile, by combining the nonlinear polarization rotation effect and the hybrid mode-locking mechanism of the few-layer black phosphorus, the mode-locking threshold is significantly reduced, and the long-term stability of the pulse is improved. The laser can realize stable emission of up to six wavelengths at the same time, the wavelength drift is less than 0.75 nm, and the power fluctuation is less than 7.0 dB.

The present invention discloses a C-band passively Q-switched pulsed fiber laser and a preparation method of a saturable absorber based on CsPbBr3 perovskite nanocrystals, belonging to the field of laser technology. The fiber laser is composed of a pump source, a wavelength division multiplexer, an erbium-doped gain fiber, an optical isolator, a saturable absorber based on a CsPbBr3 perovskite nanocrystal thin film, and a fiber output coupler connected in series end to end in sequence; in the present invention, the prepared CsPbBr3 perovskite nanocrystal thin film saturable absorber is inserted into the fiber laser cavity. Due to the characteristics of large optical absorption coefficient, high carrier mobility, low defect density, high gain value, and low saturation intensity of CsPbBr3 perovskite nanocrystals, it is more conducive to the output of Q-switched pulsed laser; the central wavelength of the Q-switched pulsed laser is about 1560 nm in the C-band, the maximum pulse repetition frequency is 49.70 kHz, the maximum output power is 1.9 mW, and the shortest pulse width is 7.92 μs.