1060results about "Optical resonator shape and construction" patented technology

The invention belongs to the technical field of topological photonic crystals, and discloses a topological laser resonant cavity, a design method thereof and a topological valley photonic crystal laser. According to the invention, three different photonic crystal areas are utilized to form a three-layer heterostructure, and the three different photonic crystal areas are divided into A, B and A'areas according to the same lattice period array arrangement; the area A and the area A'are the innermost layer and the outermost layer of the topological laser resonant cavity respectively, the closed topological laser resonant cavity is formed at the interface of the area A and the area A ', and the area B is embedded in the middle of the interface; the three different photonic crystal regions have different primitive cell energy band characteristics, and the energy band structure of the photonic crystal primitive cell in the region B has a linear dispersion curve and can be described by a Dirac equation; and the photonic crystal primitive cells in the A'and the A region are energy band structures with different topological valley numbers obtained by breaking the symmetry of the photonic crystal primitive cells in the B region. According to the invention, the performance of the topological valley photonic crystal laser can be enhanced.

The invention provides an all-solid-state high-power single-frequency laser based on an optical fiber-slab mixed structure, and relates to the technical field of solid lasers, and the all-solid-state high-power single-frequency laser comprises an all-solid-state continuous single-frequency seed module, an optical fiber pulse modulation module, an optical fiber pre-amplification module, a slab laser pre-amplification module, a slab laser main amplification module and a frequency multiplication module which are sequentially arranged; the lath laser pre-amplifier and the lath laser main amplifier are used for compensating thermally induced aberration generated by lath laser through multi-pass amplification designed according to the spherical aberration self-compensation principle, and then the quality of light beams is improved. In addition, a discrete mirror group is adopted to replace a complete amplifier cavity mirror, spontaneous radiation and parasitic oscillation in the working process of the amplifier are effectively restrained, nearly hundred mJ-magnitude single-frequency pulse laser with excellent light beam quality can be obtained, and application to laser radar detection or industry can be met.

The invention provides a dual-wavelength tunable all-solid-state mid-far infrared laser, relates to the technical field of lasers, and is used for solving the technical problems that high-performance dual-wavelength 3 [mu] m waveband laser and mid-far infrared waveband laser generated by pumping of the high-performance dual-wavelength 3 [mu] m waveband laser are difficult to obtain in the prior art. The middle and far infrared laser comprises an erbium-doped laser and an optical parametric oscillator, the erbium-doped laser is used for providing dual-wavelength 3-micron wave band pulse laser, and the erbium-doped laser comprises a pumping source, an erbium-doped laser medium, a gain modulator, a high reflective mirror and an output mirror; the optical parametric oscillator is used for obtaining medium-wave infrared laser and long-wave infrared laser which are output in a dual-wavelength mode under the pumping effect of the dual-wavelength pulse laser in the 3-micron wave band. The mid-far infrared laser is simple in structure and convenient to use, can obtain tunable dual-wavelength mid-far infrared pulse laser with high beam quality, and meets the light source requirements of differential absorption of toxic gas telemetering of laser radar and photoelectric countermeasure.

The invention discloses a method for generating high-quality Laguerre-Gaussian vortex light, which comprises the following steps: based on a V-shaped laser resonant cavity of a concave folded mirror, astigmatism is introduced by utilizing different convergence capacities of the concave folded mirror on a meridian plane and a sagittal plane of a light beam, so that the cylindrical symmetry of the resonant cavity is destroyed, and the high-quality Laguerre-Gaussian vortex light is generated; the influence of the cylindrical symmetry of the laser resonant cavity on the intrinsic mode of the cavity is eliminated, so that the intrinsic mode of the cavity is a Hermite-Gaussian mode, and the generation of an ellipse due-Gaussian mode is inhibited; an off-axis pumping method is adopted, and the laser resonant cavity generates high-order Hermite-Gaussian mode laser; the focusing lens focuses the generated high-order Hermite-Gaussian mode laser, so that the beam waist of the high-order Hermite-Gaussian mode laser is positioned in the center of the astigmatism mode converter; the astigmatism mode converter provides conditions for mode conversion by changing the Gouy phase of the laser mode, and high-quality Laguerre-Gaussian vortex light output is achieved.

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.

The invention discloses an all-solid-state debugging-free slab laser based on an orthogonal Porro prism, and belongs to the technical field of solid laser. The diode stack array is used as a pumping source; the pumping shaping system performs homogenization shaping on the slow axis direction of the diode stack array; the coupling cavity mirror introduces the shaped light field into the lath laser crystal, and is used as an oscillation laser reflector at the same time; the ridges of the first Porro prism and the second Porro prism are mutually orthogonal; a light field introduced into the slab laser crystal reaches the first Porro prism through the polaroid, enters the coupling cavity mirror through the polaroid after being reflected, is subjected to repeated reciprocating oscillation on the end face where the coupling cavity mirror is located and the end face where the first reflector and the second reflector which are longitudinally arranged are located to reach the second Porro prism, and then returns to the first Porro prism along the original path; and the light is output by the polaroid. Large single pulse energy can be output based on a single resonant cavity, cascade amplification is not needed, the system size compactness is very high, and the photoelectric conversion efficiency is high.

The invention relates to a miniaturized medium-long wave infrared solid-state laser in which a thulium-doped laser directly pumps a ZGP crystal, the thulium-doped laser takes two laser diodes with the central emission wavelength of 793 nm as pumping sources, two Tm: YAP crystals with the same parameters are cascaded and placed in a U-shaped resonant cavity to serve as laser gain media, and an acousto-optic Q crystal controls intra-cavity loss in the resonant cavity, so that the thulium-doped laser directly pumps the ZGP crystal. Pulse laser with the wavelength of 1.94 m is output; the 1.94 m pulse thulium laser serves as pump light and passes through the ZGP-OPO module, and 2.8 m signal light and 6.2 m idler frequency light are obtained. The Tm laser outputs 1.94 m laser through primary oscillation to directly serve as a pump source, the ZGP-OPO outputs medium-long wave infrared laser in a nonlinear mode, the overall light path structure of the medium-long wave laser is simplified, and the electro-optical conversion efficiency is improved.

The invention relates to the technical field of all-solid-state laser, and provides a thermal stress self-matching laser device and a regulation and control method thereof. The resonant cavity oscillates the pumping laser, and an input lens and an output lens are oppositely arranged in the resonant cavity; the gain medium is arranged between the input lens and the output lens; the stress self-adaptive heat sink is used for dissipating heat and can monitor and adjust a real-time stress value borne by the gain medium; the power meter is arranged at the downstream of the output lens along the light path and is used for measuring the power of the output laser; a stress threshold value is preset in the processor; and the processor is used for controlling the stress adaptive heat sink to adjust the real-time stress value based on the power and the stress threshold value, so that the power meets a preset requirement. According to the invention, the stress of the gain medium in the operation process of the laser is monitored, regulated and controlled, and the stress matching of the gain medium is realized, so that the thermally induced stress damage risk of the gain medium is reduced.

The invention discloses a green laser and a laser welding machine. The green laser comprises a pumping source, a first reflector, a laser crystal, a polarization beam splitter, a second reflector, a frequency doubling crystal, a telescope lens group and a spectroscope; the pumping source provides pulse pumping light; the laser crystal absorbs the pulse pump light to generate fundamental frequency laser in an infrared band, the fundamental frequency laser enters the polarization beam splitter and is split into P polarized light and S polarized light, the P polarized light is transmitted out of the resonant cavity, and the S polarized light is transmitted in the resonant cavity; and the telescope lens group converges the fundamental frequency laser to the frequency doubling crystal to generate frequency doubling laser of a green light wave band, and the frequency doubling laser is transmitted by the spectroscope and then is output. The green laser is used for spot welding of high-reflection materials such as copper and aluminum, the maximum single pulse energy can reach 5 J, the maximum peak power is 2 kW, the pulse width ranges from 0.05 ms to 5 ms, the problem of low absorption of the high-reflection materials to laser in the 1-micron wave band is solved, and the green laser is an edge tool for precise spot welding of the high-reflection materials.

The invention belongs to the technical field of laser pulse modulation, and particularly relates to an ultrafast laser multi-pulse sequence preparation device and method. According to the invention, ultrafast pulse laser is divided into a transmission light path and a reflection light path through a beam splitter, a spatial light modulator is utilized to perform programming control on a target pulse in the transmission light path, and amplitude and pulse width parameters can be controlled while multiple pulse strings are generated; and the light path of the reflection light path is controlled through the high-precision one-dimensional displacement table, so that the time delay of a reflection light path pulse relative to a transmission light path pulse is controlled. And after the reflected light path and the transmission path subjected to pulse shaping are combined again, a periodic pulse string sequence with controllable time delay, pulse number, pulse width parameter and pulse intensity is realized. The problem that high-precision multi-pulse dynamic programming cannot be achieved through a traditional adjusting mode is solved, and the problems that in the prior art, the number of excitation pulses and pulse width parameters cannot be controlled at the same time, and an ordered periodic pulse sequence cannot be generated are solved.

The invention relates to a microsphere laser and a preparation method thereof, the microsphere laser comprises an optical fiber, microspheres and a pump light source, the microspheres are erbium-ytterbium co-doped microspheres containing erbium ions and ytterbium ions, the number of the microspheres is two, the microspheres are respectively a first microsphere and a second microsphere, the diameter of the first microsphere is smaller than that of the second microsphere, and the pump light source is arranged between the optical fiber and the pump light source. A conical area which is gradually shrunk from the two ends to the middle is arranged at the position, close to the center, of the optical fiber, the first end of the conical area is close to the pump light source, the second end of the conical area is far away from the pump light source, and the two microspheres are located on the upper side and the lower side of the conical area of the optical fiber respectively. The first microsphere is disposed proximate a first end of the tapered region to couple with a first end of the optical fiber, and the second microsphere is disposed proximate a second end of the tapered region to couple with a second end of the optical fiber. Through the arrangement form of the two microspheres, the optical fiber and the pump light source, the threshold value is reduced.

To provide mechanisms for providing a source for circular-ranging OCT at moderate speeds.SOLUTION: A source for providing electromagnetic radiation within a particular spectral range includes: a ring-shaped optical resonator for circulating a plurality of wavelength bands including a first optical phase modulator, a first chromatic dispersion device, a second optical phase modulator, a multi-line spectral domain filter, a second chromatic dispersion device, and an optical amplifier; and a controller coupled to the first optical phase modulator and the second optical phase modulator, the controller being configured to drive the first optical phase modulator with a first waveform and the second optical phase modulator with a second waveform.SELECTED DRAWING: Figure 2

The invention provides a low repetition frequency wide spectrum laser based on out-of-cavity broadening and an imaging system thereof.The laser comprises an ultrafast pulse generation long cavity, a spectrum broadening unit and a time domain stretching unit which are connected in sequence, and the ultrafast pulse generation long cavity is used for generating ultrafast pulses with low repetition frequency and high phase coherence; the spectrum broadening unit is used for carrying out spectrum broadening on the ultrafast pulse to obtain a low repetition frequency broadened pulse, and the time domain stretching unit is used for carrying out time domain stretching on the low repetition frequency broadened pulse to obtain low repetition frequency wide spectrum laser. When the low-repetition-frequency wide-spectrum laser is applied to an imaging system, the imaging speed, the longitudinal resolution and the imaging quality can be improved, and the broadband requirements of imaging on a detector and a data acquisition card are reduced.

A grain-oriented electrical steel sheet according to an embodiment of the present disclosure includes: an electrical steel sheet substrate; and an insulating film layer that is disposed on the electrical steel sheet substrate. At least one deformation portion having a linear shape is formed on a surface of the electrical steel sheet substrate, and a natural corrosion potential value of the electrical steel sheet is -350 mV or more.

The invention discloses a dual-wavelength microsphere laser based on tri-doped rare earth ions and a preparation method thereof, the dual-wavelength microsphere laser based on tri-doped rare earth ions comprises a silica fiber, the middle part of the silica fiber is provided with a conical region; the pump light source is arranged at one end of the silica fiber; the erbium, holmium and ytterbium tri-doped tellurate glass microspheres are arranged in the conical region; pump light emitted by the pump light source is guided to the conical region through the single-mode optical fiber and is optically coupled with the erbium-holmium-ytterbium tri-doped tellurate glass microsphere; in the erbium-holmium-ytterbium triple-doped tellurate glass microspheres, infrared-transmitting tellurate glass is used as a matrix, and the doping amount of an erbium element is 0.11%, the doping amount of a holmium element is 0.22%, and the doping amount of an ytterbium element is 0.80% in percentage by mass. According to the dual-wavelength microsphere laser based on the three-doped rare earth ions, efficient and stable dual-wavelength laser output is achieved.

A first pumping source and a second pumping source are combined through a pumping beam combiner and are coupled into an erbium-doped fluoride fiber and a high-reflectivity fiber bragg grating, and the erbium-doped fluoride fiber and a low-reflectivity fiber bragg grating form a laser resonant cavity. The intermediate infrared laser is output through the low-reflectivity fiber bragg grating, the cladding light filter and the optical fiber end cap; the high-reflectivity fiber bragg grating and the low-reflectivity fiber bragg grating have the same grating period, the fourth-order harmonic reflection wavelength of the grating is located in the emission spectrum range of transition of erbium ions from the 4F9 / 2 energy level to the 4I9 / 2 energy level, and the fifth-order harmonic reflection wavelength of the grating is located in the emission spectrum range of transition of erbium ions from the 4I11 / 2 energy level to the 4I13 / 2 energy level; by adjusting the power of the first pumping source and the second pumping source, the net gain of laser transitions from the 4F9 / 2 energy level to the 4I9 / 2 energy level and transitions from the 4I11 / 2 energy level to the 4I13 / 2 energy level is regulated and controlled, and switching of laser working wavelengths is achieved.

The invention belongs to the technical field of light field modulation, and particularly relates to a light field modulation method based on a Fabry-Perot microcavity internal device. The method comprises the following steps: based on a micro-nano light processing scheme, constructing a Fabry-Perot microcavity laser based on intracavity low-light element light field shaping, and then placing the laser in a light field test system; the method comprises the following steps: (1) detecting an output laser pattern, and controllably constraining and modulating an intracavity light field by adjusting the position of a laser; (2) detecting an output laser spectrum, further adjusting the pumping energy to obtain a relation between a spectrum peak value and the pumping energy, and realizing high-quality factor single-mode laser; by designing the matching relation between the optical continuous interface or diffraction structure configuration and the micro-cavity configuration in the micro-cavity laser, the performance parameters of the Fabry-Perot micro-cavity and the modulation of the intra-cavity light field can be realized, so that the high-quality factor micro-cavity laser and the customized output of the light field in a specific laser mode are realized.

The invention discloses a periodic forked near-transformation limit nanosecond pulse mode-locked fiber laser and a generation method. The laser is characterized in that a fiber ring cavity comprises a wavelength division multiplexer, an erbium-doped fiber, a first polarization controller, a polarization analyzer, a dispersion control unit, an output coupler, a fiber isolator and a second polarization controller which are sequentially connected in a closed loop mode. 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 fiber and is stimulated to radiate a gain pulse with a long wave band, and the generated pulse oscillates in a fiber laser cavity; under the combined action of a first polarization controller, an analyzer and a second polarization controller, an equivalent saturated absorption effect is generated by utilizing nonlinear polarization rotation generated when gain pulses are propagated in an optical fiber, and pulse mode locking is realized; the optical fiber laser works in an abnormal dispersion region, so that generated pulses meet the soliton area theorem, and near-transformation limit pulses are generated. According to the invention, nanosecond pulse period bifurcation output of the short-cavity fiber laser can be realized.

The invention discloses an air-cooled miniature slab laser based on double-end pumping, and belongs to the technical field of solid laser. Wherein the first conduction cooling single bar and the second conduction cooling single bar are arranged at the upper end and the lower end of the lath laser crystal in a staggered manner to form a double-end pumping structure; after the first fast axis collimation cylindrical lens and the second fast axis collimation cylindrical lens respectively collimate the fast axis directions of the first conduction cooling single bar and the second conduction cooling single bar, partial end surfaces are injected into the lath laser crystal; the first resonant cavity reflector and the second resonant cavity reflector are located at the left end and the right end of the lath laser crystal; the laser injected into the slab laser crystal passes through the resonant cavity mirror and then is subjected to multi-pass back-and-forth oscillation between the first resonant cavity reflector and the second resonant cavity reflector to reach the resonant cavity output cavity mirror. The output monopulse energy is greatly improved, the overall electro-optical efficiency is high, and the system compactness is high.

The invention relates to a high-power dual-wavelength erbium-doped solid laser, and belongs to the technical field of laser. The high-power dual-wavelength erbium-doped solid laser comprises a pumping source, a pumping cavity, a diamond, a heat sink, a first resonant cavity and a second resonant cavity, the first resonant cavity comprises a first erbium-doped YAG slice crystal, and the second resonant cavity comprises a second erbium-doped YAG slice crystal. The first erbium-doped YAG sheet crystal is used for generating 1.64 [mu] m laser which oscillates back and forth in a back-and-forth light path provided by the first resonant cavity; and the second erbium-doped YAG sheet crystal is used for generating 2.94 [mu] m laser which oscillates back and forth in a back-and-forth light path provided by the second resonant cavity. According to the high-power dual-wavelength erbium-doped solid laser provided by the invention, synchronous output of 1.64 mu m and 2.94 mu m dual-wavelength laser is realized, the multifunctionality and medical adaptability of the laser are enhanced, and multi-type treatment requirements of soft tissues and hard tissues can be met at the same time.

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 an all-polarization-maintaining optical fiber mode-locked laser which comprises a linear cavity and an annular cavity. Wherein the annular cavity consists of a wavelength division multiplexer, an optical fiber coupler, a phase bias device, a gain optical fiber and a dispersion compensation optical fiber; the linear cavity is composed of an optical fiber coupler and an optical fiber reflector. As a function multiplexing device, an external electric field is applied to the phase bias device, so that the functions of continuous tuning of the phase difference in the positive direction and the negative direction in the annular cavity of the 9-shaped cavity mode-locked fiber laser and rapid phase tuning are realized, and the realization of a mode-locked state and a high-precision phase locking state is promoted. In addition, the composition structure of the resonant cavity can be simplified, and the repetition frequency and the system stability of the mode-locked laser can be improved. The technology for constructing the 9-shaped cavity mode-locked fiber laser by adopting the active phase bias device has originality in the field of ultrafast optics, and a better choice is provided for the all-polarization-maintaining fiber mode-locked laser.

A system and method for locking laser frequency based on a hollow fiber FP resonant cavity are characterized in that the output end of a laser is connected with the first port of an optical fiber circulator, the second port of the optical fiber circulator is connected with the input end of an optical fiber coupler, and the first output end of the optical fiber coupler is connected with the input end of a polarization controller; a second output end of the optical fiber coupler is connected with an input end of the optical trap, an output end of the polarization controller is connected with an input end of the hollow-core optical fiber Fabry-Perot resonant cavity, and an output end of the hollow-core optical fiber Fabry-Perot resonant cavity is connected with a third port of the optical fiber circulator; the second output end of the optical fiber coupler is connected with the input end of the optical trap, the second output end of the optical fiber coupler is aligned with the input end of the optical trap, and optical signals output by the second output end of the optical fiber coupler directly enter the optical trap. The system is simple in structure, low in implementation cost, wide in locking range, high in anti-interference capability and high in integration degree.

An ultraviolet (UV) light source includes a light emitting element that is configured to generate light of a first frequency, a nonlinear optical element that is configured to receive the light of the first frequency from the light emitting element and generate UVC or far-UVC light of a second frequency from the light of the first frequency, and an output coupling element that is configured to selectively outcouple the UVC or far-UVC light from the nonlinear optical element as output light. Related light sources and fabrication methods are also discussed.

A line narrowing device includes a first prism; first and second gratings arranged on the optical path of the light beam having passed through the first prism at positions different in a direction of grooves of either the first grating or the second grating; a beam adjustment optical system arranged on the optical path of the light beam between the first prism and at least one grating of the first and second gratings, and causing a first portion of the light beam to be incident on the first grating and causing a second portion of the light beam to be incident on the second grating; a first actuator adjusting an incident angle of the first portion on the first grating; second actuator adjusting an incident angle of the second portion on the second grating; and a third actuator adjusting an energy ratio of the first and second portions.

The invention discloses an adjustable optical frequency comb system and method based on a magnesium fluoride crystal micro-bottle cavity, magnesium fluoride crystals are used as a micro-bottle cavity material, and the system has the optical performance of extremely high quality factor and low absorption loss, so that the system can realize efficient optical frequency comb generation under low pumping power, and the generation efficiency and stability of the optical frequency comb are improved. The piezoelectric ceramic element is introduced into the structure to realize the tuning of the optical frequency comb, and the application of the piezoelectric fine tuning module enables the stress tuning of the micro-bottle cavity to be more accurate and flexible. Through fine adjustment of the axial stress applied to the micro-bottle cavity, rapid tuning of the positions of the comb teeth of the optical frequency comb can be realized, the system structure and the operation process are simplified, and the usability of the system is improved. The adjustability of the optical frequency comb is realized under the condition that the optical frequency of the pump laser is not changed, and the stability and the anti-interference capability of the system are greatly enhanced. Meanwhile, the stable mode field in the micro-bottle cavity provides high signal quality, the output stability of the optical frequency comb is improved, and the application value of the system is enhanced.

The invention discloses a solid laser with a heat effect reducing structure, and relates to the technical field of lasers, the solid laser comprises a laser gain medium, a pump light source and a heat management module, the laser gain medium is arranged in a laser resonant cavity formed by at least one reflector, the pump light source is used for exciting the laser gain medium, and the heat management module is used for controlling the heat effect reducing structure. The heat management module comprises a heat conduction substrate, a plurality of micro-channel cooling structures arranged in parallel along the interior of the heat conduction substrate, a heat diffusion layer and a heat interface material. By installing the rectangular micro-channel cooling structure, local heat generated by the laser gain medium is efficiently absorbed and conducted, uniform cooling is achieved, local overheating, hot plate and thermal lens effects are effectively prevented, optical distortion and device deformation caused by thermal gradient on the surface are avoided, the overall thermal management efficiency is improved, and the service life of the laser is prolonged. The laser is ensured to work stably under a high-power operation condition, the service life of the device is prolonged, and the output beam quality is improved.

A line narrowing device includes a first prism; first and second gratings arranged on the optical path of the light beam having passed through the first prism at positions different in a direction of grooves of either the first grating or the second grating; a beam adjustment optical system arranged on the optical path of the light beam between the first prism and at least one grating of the first and second gratings, and causing a first portion of the light beam to be incident on the first grating and causing a second portion of the light beam to be incident on the second grating; a first actuator adjusting an incident angle of the first portion on the first grating; a second actuator adjusting an incident angle of the second portion on the second grating; and a third actuator adjusting an energy ratio of the first and second portions.

The utility model provides an NPE mode-locking polarization-maintaining large-mode-field fiber laser with enhanced self-starting capability, and relates to the technical field of fiber lasers, the fiber laser comprises a pumping source and a laser oscillation cavity, the pumping source is connected with a gain fiber through a fiber beam combiner, and the laser oscillation cavity is connected with the gain fiber through a fiber beam combiner. The gain fiber is connected with a spatial light path of the laser oscillation cavity part through the photonic crystal fiber, a polarization beam splitter is arranged in the laser oscillation cavity, and a phase shifter is arranged between the polarization beam splitter and a spatial light path of the pumping source part and used for realizing nonlinear polarization rotation (NPE) mode locking; the polarization beam splitter is arranged at the position where two orthogonal polarization states transmitted in the optical fiber interfere, dual-port output of the laser is provided, vertical polarized light is output from a reflection port, horizontal polarized light is output from a transmission port, and the mode locking self-starting capacity and stability of the laser are improved.

To provide a laser device which can make the output energy large.SOLUTION: A laser device includes an oscillator which emits pulse-shaped seed light, a first amplifier which amplifies the seed light and emits first amplified light, a first pulse extender that extends the pulse width of the first amplified light, a beam splitter that divides the first amplified light with the extended pulse width into first split light and second split light with less energy than the first split light, a second amplifier that amplifies a portion of the second split light and emits a second amplified light, a second pulse stretcher that stretches the pulse width of the second amplified light, and a beam combiner that emits combined light that combines the first split light and the second amplified light whose pulse width has been stretched.SELECTED DRAWING: Figure 3