40 results about "Mode-locking" patented technology

The invention provides a femtosecond pulse width precision adjustment compensation device and method, and relates to the technical field of laser processing, the device comprises a mode locking seed source, a stretcher, an amplifier, a first compressor and a second compressor; the second compressor comprises a movable reflecting mirror, a climbing mirror, a grating and a grating base material; the movable reflecting mirror is configured to adjust the diffraction times of the femtosecond laser on the grating by changing the distance between the movable reflecting mirror and the grating base material; the grating base material is made of a nonlinear material and is used for generating a self-phase modulation effect under the action of femtosecond laser to realize spectrum broadening and pulse compression; precise adjustment compensation of the femtosecond pulse width is achieved by adjusting the diffraction times. The invention provides a technical scheme which not only can bear high-power and high-energy laser, but also can realize on-line precise adjustment and compensation of pulse width.

The invention discloses a near-infrared wide-spectrum pulse light source generator, belongs to the technical field of laser light source manufacturing, and aims to solve the problems of complex system structure and high cost due to the fact that a supercontinuum laser generates supercontinuum through multi-stage power amplification in the prior art. The device is composed of a first semiconductor pump laser, a first wavelength division multiplexer, a first gain optical fiber, a first filter, a first dispersion compensation optical fiber, a first high-nonlinearity optical fiber, a first isolator, an optical fiber coupler, a second semiconductor pump laser, a second wavelength division multiplexer, a second gain optical fiber, a second filter, a second dispersion compensation optical fiber, a second high-nonlinearity optical fiber and a second isolator. According to the invention, the characteristic of high mode-locked pulse energy of the Mmyshev oscillator is utilized, multi-stage power amplification is not needed, and the super-continuum spectrum can be directly generated, so that the system structure is simplified, and the cost is reduced; the laser light source can be applied to multiple fields of laser sensing, photoelectric countermeasure, remote sensing detection, optical imaging and the like.

The invention discloses a 2-micron short-period laser amplifier based on a thulium-doped positive dispersion fluorotellurite optical fiber, which can solve the problem that a negative dispersion thulium-doped optical fiber is not suitable for performing gain management nonlinear amplification on a 2-micron pulse, and can obtain a pulse width lt. 50 fs, and single pulse energy gt; the femtosecond laser output device has the advantages of being full-fibrillated and compact in structure. The 2-micron femtosecond seed source is femtosecond pulse laser of a 2-micron wave band generated based on nonlinear amplification loop mirror mode locking; the chirped pulse amplifier is used for obtaining sub-picosecond 1.9 mu m femtosecond laser output with the average power greater than or equal to 1W; the optical fiber GMN amplifier is used for obtaining a few-period femtosecond pulse; the high-power optical fiber pulse compressor is a hollow-core optical fiber and is used for carrying out accurate dispersion compensation and high-quality pulse compression.

The present application relates to a dual-comb laser, and in particular to a direction-polarization multiplexing single-cavity dual-comb laser, which solves the technical problems of the prior art that pulse components in different polarization directions are difficult to separate, leading to high difficulty in dual-polarization mode locking, harsh implementation conditions, or difficulty in adjusting the pulse repetition frequency difference, and the numerical value is small, or the mutual coherence of the output pulse sequence is low, and the signal-to-noise ratio is low. The present application adopts a full polarization maintaining optical fiber resonant cavity with a polarization beam splitter as a central node and a double-linked ring cavity structure composed of ring structure A and ring structure B. The laser transmitted in the counterclockwise direction in the ring structure A is cut off, and the laser transmitted in the clockwise direction is separated by the polarization beam splitter and transmitted in the opposite direction in the ring structure B, partially output, and partially returned to the ring structure A, thereby realizing cyclic oscillation.

The application relates to a 9-shaped cavity laser with independently and continuously tunable wavelength and pulse width, which comprises a 9-shaped cavity oscillator and a laser parameter tuning and state monitoring feedback system. The 9-shaped cavity oscillator can realize self-starting fundamental mode locking through the introduction of a non-reciprocal device and the optimization of the positions of the devices in the 9-shaped cavity oscillator and the lengths of the optical fibers. The laser parameter tuning and state monitoring feedback system can continuously tune the wavelength and pulse width of the 9-shaped cavity oscillator, and can monitor the output state of the oscillator in real time to determine whether the oscillator is in a stable mode-locked state and control the angle of a half-wave plate and the current value of a laser diode by using a random collision recovery algorithm so that the 9-shaped cavity oscillator can always keep in a stable mode-locked state. The application can realize the independent and continuous tuning of the wavelength and pulse width of the 9-shaped cavity laser in a stable mode-locked state, and has a wide application prospect in the field of tunable lasers.

The application discloses a kind of high-power laser seed sources for multimodal medical imaging based on germanium saturable absorber, it is characterized in that, including first pump light source, second pump light source and laser resonator, the laser resonator is by first wave division multiplexer, second wave division multiplexer, erbium-doped optical fiber, polarization controller, polarization independent isolator, germanium saturable absorber, single-mode optical fiber, optical coupler sequentially connected, the first pump light source is connected with first wave division multiplexer, and second pump light source is connected with second wave division multiplexer.The germanium saturable absorber prepared in the application has good self-starting effect on pulse, the preparation method is simple, and the preparation cost is not high.And the stability of the obtained saturable absorber is good, and it can be used for passive mode locking for a long time.

The application provides a frequency stabilized laser device and a quantum communication system, and relates to the technical field of lasers.The frequency stabilized laser device comprises: a first distributed feedback laser for generating a first laser; a second distributed feedback laser for generating a second laser; an inner closed loop for cavity mode locking of the first distributed feedback laser and the second distributed feedback laser respectively, so as to suppress noise and cavity length disturbance and complete short-term stable regulation; and an outer closed loop for beat frequency processing of the first laser and the second laser according to a reference frequency, so that the frequencies of the first laser and the second laser remain stable, the long-term thermal drift of the first distributed feedback laser and the second distributed feedback laser is suppressed, and short-term and long-term stability is unified.The application can solve the technical problems that the existing laser cannot simultaneously realize short-term low noise and long-term low drift, the stable cavity effect is poor, and frequency difference monitoring is difficult, and realizes the unification of short-term stability and long-term stability of the laser signal.

The application provides a laser and a mode locking method based on a discrete echo wall microcavity, and relates to the technical field of lasers.The laser provided by the application comprises a pumping source, a resonant cavity packaging module and a feedback control module;the resonant cavity packaging module comprises a polarization maintaining fiber group, a phase modulator and an echo wall mode resonant cavity which are packaged in a shell;the polarization maintaining fiber group is coupled to the echo wall mode resonant cavity at a fixed distance;and the feedback control module is used for mode locking the resonant cavity packaging module.The laser and the mode locking method provided by the application design corresponding structures based on a discrete echo wall microcavity, solve the problem of precise coupling between an external cavity module and a laser chip, make the laser easy to assemble and deploy by realizing modular design, provide an adaptive compensation algorithm to enhance the locking effect, and provide a mode selection function for laser users to better support research in the fields of communication and calculation.

The invention discloses a repetition frequency tunable high-order collision mode-locked laser and an optical frequency comb, and the laser comprises a laser resonant cavity, the two ends of the laser resonant cavity are respectively provided with a high reflection coating end face and a low reflection coating end face, a saturable absorber SA region and a gain Gain region, the total length ratio of SA to Gain is 1: A, the resonant cavity is divided into (1 + A) large sections, each large section is divided into B small sections, and (1 + A) * B unit sections are arranged, the adjacent unit sections are electrically isolated and can be combined into an SA or Gain region through electrical connection; sA is composed of continuous B unit sections, Gain is composed of the remaining unit sections, and collision mode locking of different orders and repetition frequency tuning are achieved by changing the position of the SA. By changing the connection mode of the resonant cavity and combining with the conical ridge width structure, the high-power pulse light source with tunable repetition frequency is realized under the fixed resonant cavity, the system complexity and cost are reduced, the pulse stability and peak power are improved, and a scheme is provided for low-cost and miniaturized application.

The polarization multiplexing double-frequency comb laser with online polarization and mode locking belongs to the field of double-frequency comb lasers. The problems of large preparation difficulty of double-frequency comb optical system, instability of double-frequency comb output light source and uncontrollable power loss are solved. The passive mode locking is realized through the mode locker, and the circulating oscillation of the set direction of the resonant cavity is realized through the direction control component (polarization insensitive isolator or ring). Since the mode locker and the online polarizer are prepared by the side polished fiber, the preparation difficulty is small, the power loss is controllable, and the online polarizer is introduced to replace the traditional unstable polarization control. The online polarizer introduced makes the double-frequency comb more stable output. The present application is mainly used for generating stable double-frequency comb light.

The invention provides an intelligent control method and device for a high-power optical fiber femtosecond laser, and belongs to the technical field of optical fiber femtosecond lasers. Comprising mode locking control and temperature control, specifically, the intelligent mode locking system is controlled to perform mode locking operation according to a feedback signal of the repetition frequency detection system, the intelligent temperature control system is controlled to perform graded temperature adjustment according to a feedback signal of the temperature sampling unit, and the intelligent temperature control system is controlled to adjust temperature setting to assist in mode relocking when mode locking fails. The high-power fiber femtosecond laser control system can adapt to complex external environment changes, and fast and effective control over the high-power fiber femtosecond laser is achieved.

The present application provides a mode-locked pulse light generating filter that simply realizes self-starting mode locking, and a laser device that generates a picosecond, femtosecond pulse laser by being provided with the filter, the laser device being provided with an amplification section that amplifies light within a resonator and outputs the light, and a mode-locked pulse light generating filter that has a first filter section that selectively outputs a first wavelength component that is a wavelength component of an oscillation band within the resonator, and a second filter section that selectively outputs a second wavelength component that is a wavelength component different from the oscillation band.

The utility model belongs to the technical field of lasers, and discloses a 9-shaped hybrid mode-locked fiber laser, which comprises a pumping source, a 2 * 2 polarization-maintaining fiber coupler, a nonlinear amplification loop mirror loop connected with a first side of the polarization-maintaining fiber coupler, and a chirp fiber Bragg grating connected with a second side of the polarization-maintaining fiber coupler, the polarization maintaining optical fiber coupler is located at the connecting position of the nonlinear amplification annular mirror loop and a linear arm of the laser resonant cavity and used for coupling laser of the nonlinear amplification annular mirror loop to the linear arm, and after being reflected by the chirp fiber bragg grating, the laser is output to the nonlinear amplification annular mirror loop through the chirp fiber bragg grating. And then the laser on the linear arm is split into two beams of light which are transmitted clockwise and anticlockwise in a loop of the nonlinear amplification annular mirror. According to the utility model, two passive mode locking technologies are combined, rapid and stable mode locking can be realized, the operation state is slightly influenced by the environment, the signal-to-noise ratio of output laser pulses can be improved, and ultra-short pulses with narrower pulse width can be realized.

The invention belongs to the field of solid-state lasers, and particularly discloses a Kerr lens mode-locked self-starting-based solid-state laser which comprises a laser generating unit used for generating laser and a mode-locked regulation and control unit arranged on a laser emergent light path. And the mode-locked regulation and control unit comprises a half-wave plate, a polaroid and a target reflector which are sequentially arranged along a preset light path, and is used for regulating and controlling the light intensity of the laser reflected back to the laser generation unit in a polarization state regulation mode and triggering the mode-locked state of the Kerr lens in a light disturbance mode. According to the invention, the Kerr lens mode locking state can be effectively triggered, a traditional mechanical disturbance mode is abandoned, all-optical active triggering is realized, and the operation convenience and long-term operation stability of the laser are greatly improved; in addition, a user can adjust the laser system to an optimal mode-locking trigger state, and the success rate and repeatability of mode-locking self-starting of the Kerr lens are remarkably improved.

The invention relates to the technical field of semiconductor laser devices, in particular to a high-power-density distributed feedback type laser chip and a preparation process thereof. According to the technical scheme, the chip comprises a chip body, the chip body comprises a back electrode, a substrate, a lower waveguide layer, a lower limiting layer, an active layer, an upper limiting layer, an upper waveguide layer, a highly-doped layer and a front electrode which are sequentially stacked from bottom to top, and graphene layers are arranged on the sides, close to the active layer, of the lower limiting layer and the upper limiting layer. According to the invention, the graphene heat conduction layer and the conical bulge and micropore array are introduced between the active layer and the limiting layer, so that heat is directly and quickly dredged, thermal resistance and interface strain are reduced, heat accumulation is relieved from the source, and the reliability of the chip is improved; the artificial micro-nano grating formed by the conical structure and the DFB built-in grating cooperatively enhance longitudinal mode feedback, and improve the side mode rejection ratio and the light field limiting factor. Meanwhile, mode locking and 1 microsecond-level wavelength tuning are achieved through array type current injection, and the light spot and coupling efficiency is improved in cooperation with a unit-level micro lens.

The invention discloses a high repetition frequency wide spectrum all-fiber femtosecond oscillator with a full polarization-maintaining structure, which comprises an LD semiconductor pump laser, a polarization-maintaining wavelength division multiplexer of a DEWDM composite fiber, a PS phase delay polarization-maintaining rotating mirror, an OC polarization-maintaining fiber coupler and an AM polarization-maintaining holophote, the polarization-maintaining wavelength division multiplexer of the DEWDM composite optical fiber comprises a first polarization-maintaining single-mode optical fiber, a dispersion compensation optical fiber, a wavelength division multiplexer and a high-gain erbium-doped optical fiber. The phase delay rotating mirror is added, the mode locking self-starting characteristic is improved, the dispersion compensation optical fiber is added, dispersion management in the cavity is achieved, and narrower pulse width and wider spectrum can be obtained.

The embodiment of the invention provides a femtosecond laser beauty instrument system based on a full polarization-maintaining linear cavity seed source and a use method, and belongs to the technical field of laser equipment. The system comprises a full polarization-maintaining linear cavity femtosecond laser seed source module, a femtosecond laser amplification module, a laser transmission module, a treatment head module, an energy monitoring and feedback module and an intelligent control module. The seed source module is used for executing self-starting mode locking output by adopting a non-reciprocal mode locking mechanism; the amplification module is used for performing optical fiber amplification and pulse width compression on the femtosecond laser; the laser transmission module is used for transmitting the amplified femtosecond laser through a polarization maintaining optical fiber; the treatment head module is used for focusing the femtosecond laser transmitted to the treatment end to skin tissue; the energy monitoring and feedback module is used for detecting the fluctuation range of laser energy on line; the intelligent control module is used for integrating parameter setting and fault detection. According to the embodiment of the invention, stable output of femtosecond pulse energy can be ensured, system miniaturization and operation intellectualization are realized, and the overall cost is reduced.

The invention belongs to the technical field of lasers, and particularly provides a high repetition frequency 9-shaped cavity fiber laser which comprises a wavelength division multiplexing coupler, a laser output assembly and a nonreciprocal phase shift assembly used for generating nonlinear phase shift. The non-reciprocal phase shift assembly comprises a phase shifter and a tapering optical fiber; the phase shifter is located on an emergent light path of the wavelength division multiplexing coupler; the input end of the tapering optical fiber is located on an emergent light path of the phase shifter, and the output end of the tapering optical fiber is connected with the wavelength division multiplexing coupler; the laser output assembly is connected with the wavelength division multiplexing coupler; and the laser output assembly is used for reflecting one part of the laser input by the wavelength division multiplexing coupler back to the wavelength division multiplexing coupler and outputting the other part of the laser. According to the high repetition frequency 9-shaped cavity fiber laser, the tapering fiber area is integrated in the non-reciprocal phase shift section, so that non-linear phase shift enough for mode locking can be generated without a very long passive fiber, the cavity length is shortened, the repetition frequency is improved, and the fiber laser can output laser with high repetition frequency.

The invention relates to a broadband measurement system and method based on Rydberg atoms, and belongs to the technical field of spectrum measurement. According to the system, the frequency of the local oscillation field applied to the atomic gas chamber is scanned, the frequency spectrums of the obtained intermediate frequency signals are continuously collected, and finally the broadband frequency spectrum information is obtained through splicing, so that the technical problems existing in the optical frequency comb mode locking process are solved, and cross-multi-frequency-range broadband electromagnetic frequency spectrum monitoring can be realized. According to the invention, the electromagnetic spectrum can be measured through the Rydberg probe. The microstrip line structure can generate a strong electric field on the surface and is small in size, so that the microstrip line structure is combined with the atomic probe to form the integrated atomic probe. Therefore, the measurement range of Rydberg atoms is expanded from a resonance point to a non-resonance point by using a heterodyne method, and the optimal sensitivity is-100dBm / Hz.

The application discloses an all-fiber time-space mode-locked laser, which comprises a pump source, a beam combiner, a multimode gain optical fiber, a coupler, a filter, an isolator and a mode-locked device, the beam combiner, the multimode gain optical fiber, the coupler, the filter, the isolator and the mode-locked device are sequentially arranged and fused to form a ring-shaped laser resonant cavity; the pump light emitted by the pump source is coupled into the multimode gain optical fiber through the beam combiner; the multimode gain optical fiber absorbs the pump light, forms population inversion and generates a laser beam; the laser beam is coupled out to the filter through the coupler, the filter transmits the laser beam to the isolator after performing spectral filtering on the laser beam; the laser beam is transmitted to the mode-locked device after passing through the isolator, and the laser beam realizes time-space mode locking through the mode-locked device. Through the multimode gain optical fiber, the mode-locked device, the filter, the isolator, the beam combiner, the coupler and other devices, high-power, high-beam-quality and stable time-space mode-locked laser output is realized.

The application provides a self-locked mode VECSEL mode-stable chip packaging device, method and control method. The packaging device comprises a gain chip, a metal round sheet and a pressure device. The pressure device is arranged on the lower surface of the metal round sheet and is used for generating pressure to deform the metal round sheet and the gain chip. When the surface deformation focal length of the gain chip reaches one half of the central deformation, the nonlinear equivalent focal length of the gain chip is enhanced, mode stabilization is achieved, and the nonlinear equivalent focal length is adjusted by the surface deformation self-defocusing focal length of the gain chip and the nonlinear Kerr lens focal length determined by the material inside the gain chip. The packaging device has the advantages of simple structure, convenient operation and convenience for stabilizing the output of self-locked mode pulses. The packaging method can achieve stable mode locking at a low power without continuously increasing the pump power to increase the light intensity to achieve a stable mode locking state.

This application provides a tunable optical pulse source chip, relating to the field of semiconductor optoelectronic integrated device technology. The optical pulse source chip includes: a gain region for generating and amplifying an optical signal; a pulse selection region for receiving an external periodic electrical signal to form a periodically switching switching window, through which the amplified optical signal passes or is blocked; and a saturable absorption region for nonlinearly absorbing the optical signal passing through the pulse selection region to achieve mode locking, thereby generating and outputting an optical pulse. The repetition frequency of the optical pulse is tunable by controlling the frequency of the periodic electrical signal. This application integrates the gain region, pulse selection region, and saturable absorption region monolithically, and uses a periodic electrical signal to control the switching window of the pulse selection region. The output optical pulse repetition frequency is independently controlled by the frequency of the external electrical signal, decoupling the repetition frequency from the cavity length, thus enabling a wide-range, continuously tunable pulse repetition frequency.

The invention relates to an opto-mechanical microwave clock (100, 300, 400) integrated on a chip (103), comprising:-an optical waveguide (102) arranged on the chip (103),-a nanocavity (101) arranged substantially parallel to the optical waveguide (102), in which a modulation frequency of an optical mode excited in the nanocavity (101) corresponds to an oscillation frequency of a mechanical mode of the nanocavity (101), the modulated optical mode is evanescently coupled with the optical waveguide (102) in at least one coupling region; wherein the opto-mechanical clock (100, 300, 400) further comprises:-mode locking means configured to control opto-mechanical oscillation stability of the opto-mechanical microwave clock, the mode locking means comprising at least one of a contactless radio frequency mode locking means, an acoustic passive automatic mode locking means, an optical mode locking means comprising an optical ring resonator.

The application discloses a mode locking system and mode locking method suitable for micro-cavity ultrasonic detection, and the system comprises a control module, a laser output module and a detection module; the laser output module comprises a single-frequency laser, a temperature adjusting unit, a temperature detecting unit and a heat transfer unit, the detection module is used for detecting transmission spectrum lines of the micro-cavity ultrasonic probe and transmitting the transmission spectrum lines to the control module; the control module is used for controlling the intracavity temperature of the single-frequency laser through linear interpolation data, realizing linear regulation and scanning of the intracavity wavelength, screening and locking the micro-cavity mode of the micro-cavity ultrasonic probe; and the control module is also used for detecting the locking point of the micro-cavity mode by adopting temperature detection and light intensity voltage feedback design, automatically adjusting the temperature for wavelength adjustment in the mode drift process, and correcting the mode drift of the micro-cavity. The application can independently complete the functions of micro-cavity ultrasonic probe mode scanning, active mode selection and mode locking, and provides a new scheme which is stable, reliable, low in cost and high in sensitivity for ultrasonic detection.

This invention discloses a precision laser selective melting system based on a high-repetition-rate femtosecond laser pulse train. The system includes a substrate forming unit, a displacement system, a powder spreading system, an environmental control system, a control system, a laser system, a scanning system, and a forming chamber. This invention employs passive mode-locking technology with an ultrashort fiber resonator to generate high-repetition-rate pulses. Through pulse broadening, modulation amplification, and recompression, a high-repetition-rate femtosecond laser output is achieved, which is then focused onto the powder surface by the scanning system. The control system is connected to the displacement system, powder spreading system, laser system, and scanning system to control the entire laser selective melting process. The laser selective melting system of this invention uses an ultrafast laser with a repetition rate exceeding 1 GHz and modulated pulses instead of the continuous-wave laser in existing equipment, balancing high heating rate and energy utilization efficiency, thereby improving efficiency while reducing energy consumption.

The invention discloses an ultra-narrow linewidth fiber laser based on distributed feedback and an output method, and belongs to the technical field of electric power communication link monitoring. The laser comprises an erbium-doped optical fiber amplifier, an optical isolator, a polarization controller, a line width compression and frequency selection integrated module and an output port, the output end of the erbium-doped fiber amplifier is connected with the input end of the optical isolator, the output end of the optical isolator is connected with the input end of the polarization controller, the output end of the polarization controller is connected with the input end of the line width compression and frequency selection integrated module, one output end of the line width compression and frequency selection integrated module is connected with the input end of the erbium-doped fiber amplifier, and the other output end of the erbium-doped fiber amplifier is connected with the output end of the optical isolator. The other output end is connected with the output port; by inserting the linewidth compression and frequency selection integrated module into the optical fiber loop, ultra-narrow linewidth laser output can be realized, a mode locking effect can be achieved, and high-stability laser output is realized.

The utility model relates to a mode-locked measuring device for space-time mode-locked laser. The mode-locked measuring device comprises a space-time mode-locked fiber laser, a space sampling device and a detection device which are connected in sequence, the space sampling device comprises a first optical coupler, a first collimator, a beam splitter, a first diaphragm, a second collimator, a second diaphragm and a third collimator which are connected in sequence; a first space channel is formed among the beam splitter, the first diaphragm and the second collimator; a second space channel is formed among the beam splitter, the second diaphragm and the third collimator; the first diaphragm is movably arranged between the beam splitter and the second collimator; the second diaphragm is movably arranged between the beam splitter and the third collimator; the second collimator and the third collimator are respectively connected with the detection device; the first optical coupler is connected with the output end of the space-time mode-locked fiber laser; the technical problems that a mode-locked measuring device of a traditional space-time mode-locked laser is too complex in structure and high in cost are solved.

The invention relates to a carrier envelope phase shift frequency control device and method of an optical frequency comb, the device comprises an intracavity loss modulator, an EOM crystal and a reflector, the intracavity loss modulator is used for controlling the polarization state of an optical signal incident from an optical signal source, so that the EOM crystal works at an optimal polarization modulation working point, and the EOM crystal is used for controlling the polarization state of the optical signal incident from the optical signal source; the carrier envelope phase shift frequency of the optical signal is controlled through polarization modulation of the EOM crystal; the reflector reflects the optical signal of which the polarization state is controlled by the intra-cavity loss modulator and the polarization modulation of the EOM crystal, and the reflected optical signal is recovered to the initial polarization state through the EOM crystal and the intra-cavity loss modulator and returns to the optical signal source. Compared with the prior art, the carrier envelope phase shift frequency tuning range can be widened, the modulation bandwidth can be improved, the intra-cavity loss can be reduced, the mode locking threshold can be reduced, self-starting mode locking under high repetition frequency can be realized, a shorter EOM crystal can be allowed to be used to reduce thermal interference, and the frequency locking stability of the whole optical frequency comb system can be effectively improved.

The invention discloses a high-power 4.5 GHz femtosecond laser generating device based on a Yb: KGW crystal, and belongs to the technical field of all-solid-state ultrafast laser. The device comprises a multimode pumping source, a collimation focusing system, a pair of plane mirrors serving as folding elements, a Yb: KGW crystal, a large-curvature radius concave mirror with a dispersion compensation function, a small-hole diaphragm and a large-curvature radius output coupling mirror. The length of a physical cavity is compressed by folding a light path through a plane mirror so as to realize the repetition frequency of more than GHz, and meanwhile, a laser mode at a gain crystal is increased by utilizing a large-curvature radius lens combination so as to be matched with a multimode pumping light spot. In combination with intracavity dispersion management and a hard Kerr lens mode locking technology, high-performance femtosecond laser output with the repetition frequency larger than 4 GHz and the average power larger than 3 W is finally achieved. The device is compact in structure, low in cost and good in stability, and has important application value in the fields of optical frequency combs, biological imaging, micromachining and the like.

The invention provides a space-time mode locking mode separation device based on a symmetric fused biconical taper coupler, and belongs to the technical field of laser. The device comprises a space-time mode-locked fiber laser used for generating mixed mode space-time solitons containing an LP01 mode and an LP11 mode; the symmetric fused biconical taper coupler is connected with the output end of the space-time mode-locked fiber laser and is used for separating the mixed mode space-time soliton into an independent LP01 mode and an independent LP11 mode; and the measuring assembly is connected with the output end of the symmetric fused biconical taper coupler and is used for measuring the time domain pulse sequence, the spectral information, the light spot shape and the pulse repetition frequency of the modes before and after separation. According to the invention, information-crosstalk-free accurate separation of a low-order mode (such as an LP01 mode) and a high-order mode (such as an LP11 mode) can be realized, the separation is not limited to a time domain, and effective separation of the two modes can be realized in space, so that the requirements of research on dynamic characteristics in different mode cavities and interaction between the modes are met, and the method has a wide application prospect. And powerful support is provided for the technical development of the space-time mode-locked fiber laser.