146 results about "Semiconductor saturable absorber" patented technology

The invention discloses a passive mode-locking fiber laser with a double-wavelength short pulse output. The invention has the characteristics of high stability, high efficiency, high power, high pulse repetition rate, synchronous passive laser impulse, single-line polarization, tunability, double wavelength and ultrashort pulse output. The ultrashort pulse fiber laser of the invention uses two polarization-preserving rare-earth doped (Er3+/ doped Yb3+) fibers as laser grain media, adopts a broadband polarization beam splitter spectrum and a broadband chirp polarization-preserving fiber grating and the like as cavity surface reflecting elements and chromatic dispersion compensation elements and utilizes a semiconductor saturable absorber as mode-locked elements and the like to achieve double-wavelength passive synchronous ultrashort pulse mode-locked fiber laser output. The passive mode-locking fiber laser with the double-wavelength short pulse output is a fiber laser with a novel structure of double-wavelength mode-locked ultrashort pulse output, which can achieve full-fiber.

The invention discloses a totally positive dispersion cavity mode-locked all-fiber laser which is a fiber laser structure with high repetition rate and power, simple structure and high efficiency and is an all-fibermode-locked ultrashort laser pulse laser with stable environment and novel structure. The all-fiber laser takes rare earth doped fiber as a laser gain medium, works in a totally positive dispersion area, uses a polarizing beam splitter to split light, uses a band-pass type long-period fiber grating filter for wavelength selectivity of a mode-locked laser centre and spectral filtering light pulse compression of mode-locked laser and takes a semiconductor saturable absorber as fiber laser structures. The totally positive dispersion cavity mode-locked all-fiber laser has picosecond and femtosecond light impulse length polarizing laser output and lasers with the wavelengths longer than 1 micrometer and can be used for pumping-detecting ultrafast light physical experiments or the environmental monitoring and the microwave photonics and biophysics detection of a molecular system, double-wavelength pumping-detecting ultrafast light physical experiments, frequency-combining light radiation generation, coherent anti-Stokes Raman scattering microscopy, micromachining, and the like by being amplified by a high-power fiber amplifier.

The invention discloses a double-coating large-mode-area photon crystal flysecond laser directly obtaining micro joule-level single pulse energy, belonging to the field of laser technique and nonlinear optics, where the laser main body is based on double-coating large-mode-area photon crystal optical fiber of polarization-protection structure and adopts high-power LD laser to directly pump; the laser uses grating pair to compensate dispersion, starts mode locking with the help of semiconductor saturable absorber mirror (SESAM), and controls polarization by wave plate and polarization beam splitter and implements tunable output; laser resonant cavity keeps net positive dispersion inside and runs in self-similar mode locking mode and outside-cavity dispersion compensation is made on the output pulse and the pulse is 100-200fs wide. And the advantages: the laser has good stability, and the output pulse has high energy and high repeating frequency. And the invention can effectively avoid split of pulse running at high energy.

A fiber laser system is provided with a laser cavity including at least a gain fiber, an output coupling mirror, and a saturable absorber mirror. A photo sensor detects leakage light passing through the saturable absorber mirror, for purposes of monitoring the performance of the laser system. The saturable absorber mirror may include a semiconductor saturable absorber having a Bragg reflector monolithically formed on one side thereof.

The invention provides a resonant cavity for outputting mode-locking picosecond laser and a mode-locking picosecond laser device. The mode-locking picosecond laser device comprises a pumping source, a focusing lens and the resonant cavity for outputting the mode-locking picosecond laser, and the pumping source, the focusing lens and the resonant cavity are sequentially arranged along a light path. The resonant cavity is characterized that a laser crystal, a focusing device, a Fabry-Perot etalon and a semiconductor saturable absorber mirror are arranged in the resonant cavity, and the energy density of light beams acting on the semiconductor saturable absorber mirror can be sufficient to realize continuous mode-locking owing to the focusing device. Peak power of the picosecond laser device can be accurately controlled, so that different application requirements can be effectively met advantageously. Besides, pulse width of the picosecond laser device can be controlled, so that different application requirements can be effectively met advantageously. In addition, picosecond pulse width can be tuned, operation is easy, and mode-locking stability is unaffected. A pulse width tunable device is small in size and is beneficial to saving space.

An intracavity resonant Fabry-Perot saturable absorber (R-FPSA) induces modelocking in a laser such as a fiber laser. An optical limiter such as a two photon absorber (TPA) can be used in conjunction with the R-FPSA, so that Q-switching is inhibited, resulting in laser output that is cw modelocked. By using both an R-FPSA and a TPA, the Q-switched modelocked behavior of a fiber laser is observed to evolve into cw modelocking.

The invention discloses an all-fiber pulsed laser, and belongs to the field of laser technology and nonlinear optics. The all-fiber pulsed laser includes a pump source (1), an optical combiner (2), a first gain fiber (3), a second gain fiber (4), a first reflective fiber Bragg grating (5), a second reflective fiber Bragg grating (6), an optical isolator (7), a full reflection mirror (8) and a circulator (9), and adopts a structure of linear cavity or annular cavity. By use of the rare earth-doped gain fibers as a laser modulator, with no additional external modulation source and an all-fiber structure, ultrashort pulse laser output of high stability, high power, high energy and high efficiency is achieved. Compared with a semiconductor saturable absorption mirror (SESAM) and graphene (Graphene) modulation Q, mode-locking technology, the all-fiber pulsed laser employs gain fiber for direct pulse modulation, has the advantages of simple design, compact structure and high stability, and is easier to industrialize.

The invention relates to the technical field of lasers, and provides a two-dimensional semiconductor saturable absorber mirror. The two-dimensional semiconductor saturable absorber mirror comprises an optical fiber, a two-dimensional semiconductor film attached to the optical fiber end face and a gold film attached to the two-dimensional semiconductor film. The invention further provides a preparation method of the two-dimensional semiconductor saturable absorber mirror. The preparation method comprises the steps of: cutting the optical fiber; placing the cut optical fiber and a two-dimensional semiconductor target material in a vacuum chamber, depositing two-dimensional semiconductor plasma on the optical fiber end face, forming the two-dimensional semiconductor film, and enabling the two-dimensional semiconductor film to reach the required thickness by controlling the deposition time and/or the deposition temperature; and plating the gold film on the obtained two-dimensional semiconductor film. The novel two-dimensional semiconductor saturable absorber mirror provided by the invention is composed of the optical fiber end face, the two-dimensional semiconductor film and the gold film, and has the advantages of being high in damage threshold, simple in structure, low in cost, and high in reliability.

The present invention describes a method to achieve stabilization of the repetition rate in a passive harmonic mode-locked fiber laser employing semiconductor saturable absorbers. The pulse organization is accomplished by electrically modulating the amplifier pump source that in turn optically modulates the saturable loss of semiconductor absorber. Moreover owing on an efficient modulation mechanism of the cavity loss, the method can be used to generate an actively mode-lock pulse train. The invention offers the advantages of an actively modulated mode-locked laser while maintaining the simplicity and the cost effectiveness of a passive mode-locked system. We expect that this approach combined with the use of regenerative modulation technique and polarization-maintaining fiber components will permit the generation of the dropout-free pulse trains at gigahertz repetition rates with good long-term stability and minimal cost.

The solid state laser comprises a laser gain medium (1), pumping means for pumping the laser gain medium, and a laser cavity having a first end (3) and a second end (17), wherein the laser gain medium is at, or in the vicinity of, said first end (3) of said cavity. A semiconductor saturable absorber mirror (SESAM) can be placed at the second end (17) of the cavity. The laser gain medium can comprise at least one face for receiving pumping energy from the pumping means, the face being made reflective at a laser frequency of the laser, so that it can form the first end of the laser cavity. The resulting setup used for generating femtosecond laser pulses.

A semiconductor wafer with variable transmittance, serves as a saturable absorber for performing passive Q-switching in a laser system to produce laser pulses having defined output characteristics. By translating or rotating the semiconductor saturable absorber, loss properties of a laser cavity may be altered. In this manner, the output characteristics of the laser pulses can be varied without changing other parameters of laser operation. The output characteristics may include pulse duration, pulse repetition rate, peak power and average output power of the laser pulses. The semiconductor wafer can be made of doped or undoped GaAs, AlGaAs, InP, etc. Furthermore, the tunable Q-switch may simultaneously serve as an output coupler for the laser cavity.

A design of a semiconductor saturable absorber that offers a convenient and reliable way to control/decrease the recovery time of the absorption. The absorption recovery time is controlled during the epitaxial growth by using lattice-mismatched layer(s) to induce dislocations, and implicitly non-radiative recombination centers within the nonlinear absorbing region. These lattice reformation layer(s) are interposed between the distributed Bragg reflector and the nonlinear absorption region, containing quantum-wells, quantum-dots or bulk semiconductor material. The thickness and composition of the lattice reformation layer(s) is an instrumental to control the amount of non-radiative recombination centers used to trap the optically excited carriers generated in the absorption region.

Providing a soliton mode-locked solid-state laser that includes a resonator, a first end of which is formed of a semiconductor saturable absorption mirror, a solid-state laser medium, a negative group velocity dispersion compensator for compensating for group velocity dispersion within the resonator, and an excitation optical system that outputs excitation light for exciting the solid-state laser medium, and oscillates soliton pulse laser light with a repetition frequency of not less than 1 GHz, an intensity modulator that includes a waveguide electrooptic modulator for modulating intensity of the soliton pulse laser light and a driver for applying a voltage to the waveguide electrooptic modulator according to desired information, and a nonlinear optical element for converting the intensity-modulated soliton pulse laser light to a second harmonic wave.

An Ultra-broadband graphene-based saturable absorber mirror (graphene SAM) used as passive mode locker and Q-switch of lasers was invented. The graphene SAM comprises an optical substrate, an Aurum(Au) reflection film and graphene layer(s). Combining the ultra-broadband high reflectivity of Au film with ultra-broadband saturable absorption of graphene, the graphene SAM could be used as saturable absorber for passive mode locking and Q-switching over an ultra-wide spectral range from near-infrared to mid-infrared spectral region. Compared to semiconductor saturable absorber mirror (SESAM), the graphene SAM has the advantages of ultra-broadband operation, low linear loss, easy fabrication, low cost, and enabling mass production. This invented graphene SAM will have a wide prospect of application.

The invention discloses an all-solid-state femtosecond laser of passive mode locking Nd,Y:CaF2 of diode pumping. An Nd,Y:CaF2 laser crystal of the laser receives pumping laser penetrating through an optical coupling focusing system and a dichroic mirror; a first concave mirror, a second concave mirror and the dichroic mirror form a compact type confocal folded cavity; a third concave mirror focuses gain laser in a resonant cavity to a semiconductor saturable absorber mirror; the semiconductor saturable absorber mirror is used for starting and maintaining stable mode locking; a first GTI mirror and a second GTI mirror are used for compensating for positive chromatic dispersion in the resonant cavity; a coupling output mirror is used for outputting a stable passive mode locking pulse sequence. The all-solid-state femtosecond laser formed in the mode that a pumping source based on a laser diode is obtained, CaF2 with Nd3+ and Y3+ co-doped serves as a gain medium, the GTI mirrors are used for compensating for chromatic dispersion and the semiconductor saturable absorber mirror is used for starting mode locking, and the stable mode locking pulse sequence with the pulse width of 264 fs is output inside the resonant cavity. A laser diode pumping technology is adopted, so that the all-solid-state femtosecond laser has broader application prospects.

The invention discloses a novel microchip laser supporting optical fiber output, which belongs to the fields of laser technology and non-linear optics. The novel microchip laser mainly comprises a laser diode pumping source, an optical fiber output system, an optical collimation system, a laser light gain medium and optical elements, wherein pump light enters the optical collimation system for collimating after passing through the optical fiber output system, and is focused onto the gain medium; the film-plated optical elements are arranged in front of and behind the gain medium; the gain medium and the film-plated optical elements in front of and behind the gain medium construct a laser resonant cavity with a sandwich structure; laser light generated by the laser resonant cavity returns along the incident direction of the pump light, passes through the optical collimation system once again, and is output through the optical fiber output system. The novel microchip laser has the characteristics that optical fiber output is performed during the use of an optical fiber pump without any additional output device in a sandwich microchip structure, and a fiber-core pump or a cladding pump can be adopted, so that the flexibility of a system is improved greatly; and meanwhile, the structure can also be applied to pulse modulation of materials such as semiconductor saturable absorbing mirrors, single-wall carbon nanotubes or graphene and the like, and stable pulse output is realized.

The invention relates to a totally solidified femtosecond laser with a double cavities series structure, which is made up of four semiconductor laser pumping sources, four plating sphere mirrors, two blocks of laser crystals used as gain media, two prism pairs, a fully reflector (or semiconductor saturated absorbing mirror) and a output coupling mirror. The centre wavelength outputted by the laser is 830nm, the tuning range is 100nm, and the outputted pulse width is about 100fs. The centre wavelength outputted by semiconductor pumping light source is 673nm. The laser is compact, the cost is low and the performance is stable.

The invention discloses an all-fiber pulse laser utilizing cross modulation of resonant cavities, and belongs to the fields of laser technologies and nonlinear optics. The all-fiber pulse laser mainly comprises a pumping source (1), a fiber combiner (2), a wavelength division multiplexer (2'), a first gain fiber (3), a second gain fiber (4), reflection type fiber Bragg gratings (5)(6)(7)(8), an optical isolator (9), a total reflector (0), a circulator (10), a filter (11) and an optical fiber coupler (12). According to the all-fiber pulse laser, an optical fiber doped with a rare earth element is taken as a gain medium and a saturable absorber and is of an all-fiber structure, and has the characteristics of high stability, high power, high energy and high efficiency. The all-fiber pulse laser is different from acousto-optic, electro-optic, semiconductor saturable absorber mirror (SESAM) and graphene (Graphene) Q modulation and mode-locking techniques, pulse modulation is directly carried out by utilizing the gain fiber, so that the all-fiber pulse laser is simple in design, compact in structure and cost-saving, and meanwhile, through the dual-cavity structural design utilizing the cross modulation effect of the resonant cavities, stability of system output is effectively improved.

The invention discloses a passive mode-locking laser with a tunable pulse width. The passive mode-locking laser with the tunable pulse width comprises an 880nm pumping source, a pumping light transmission optical fiber, a pumping light coupling system, a dichroic mirror, a gain crystal, a planar-concave reflecting mirror set, a cavity length regulator, a planar output mirror and a semiconductor saturable absorber, wherein the 880nm pumping source is coupled to the pumping light coupling system through the pumping light transmission optical fiber, the pumping light coupling system is coupled with the dichroic mirror, the dichroic mirror is respectively coupled with the gain crystal and the planar-concave reflecting mirror set, the gain crystal, the cavity length regulator and the planar output mirror are coupled in sequence, the planar-concave reflecting mirror set is coupled with the semiconductor saturable absorber, assemblies between the planar output mirror and the semiconductor saturable absorber jointly form a resonant cavity of a laser, the cavity length regulator is composed of two prisms, and the cavity length of the resonant cavity can be continuously adjusted by adjusting the distance between the two prisms. The passive mode-locking laser with the tunable pulse width can easily adjust the cavity length of the resonant cavity by adjusting the distance between the two prisms, continuously adjusts the laser output pulse width, obtains laser of different pulse widths, and solves the problem that continuously tunable mode locking laser with the output pulse width smaller than 100ps can not be output in the prior art.

The invention discloses a polarization-maintaining all-fiber mode-locked laser with the low repetition frequency. An optical fiber type semiconductor saturable absorption mirror, a polarization-maintaining optical fiber mode field adapter, a polarization-maintaining single mode optical fiber, a polarization-maintaining optical fiber wavelength division multiplexer, a polarization-maintaining ytterbium-doped gain optical fiber and a polarization-maintaining optical fiber grating are connected in sequence in the optical transmission direction. A pump optical transmission optical fiber is connected with the input end of the polarization-maintaining optical fiber wavelength division multiplexer, wherein the input end is located on one side of the polarization-maintaining ytterbium-doped gain optical fiber. The polarization-maintaining all-fiber mode-locked laser with the low repetition frequency is based on the semiconductor saturable absorption mirror, the optical fiber type semiconductor saturable absorption mirror and the polarization-maintaining optical fiber grating form a linear cavity structure, stable mode locking automatic start is achieved, unstable mode locking caused by external slight vibration cannot occur, the all-fiber structure is achieved, integration is easy, all optical fiber devices of the laser adopt polarization-maintaining optical fiber splicing, it is ensured that the laser can output linear polarized light, and the polarization-maintaining all-fiber mode-locked laser with the low repetition frequency is simple and compact in structure, and good in mode locking stability.

The invention discloses a method for realizing an all-fiber package of a semiconductor saturable absorption mirror. The method comprises the following steps of: uniformly spreading ultraviolet glue on the upper surface of a ceramic fiber pin except for the part of the head face of a fiber core; slowly placing a semiconductor saturable absorption mirror which is not packaged on the upper surface of the ceramic fiber pin of a fiber ferrule connector (FC) joint horizontally; and connecting a fiber at the other end of the fiber FC joint in a cavity of a fiber laser. The semiconductor saturable absorption mirror or the fiber FC joint can be changed when experiments show that parameters of the placed semiconductor saturable absorption mirror of the model fail to satisfy the experiment requirements or show that the head face of a fiber core corresponding to the semiconductor saturable absorption mirror is damaged in the experiment process; and the ultraviolet glue can be adopted to cure when the experiments provs that the various parameters of the semiconductor saturable absorption mirror are accordant with the requirements. The method provided by the invention breaks through the technological monopoly at home and abroad, and is simple in operation, low in cost and excellent in repeatability; and the method fills the blank in the technical field at home.

The present invention provides a mode-locked laser for outputting a femtosecond pulse. The mode-locked laser includes a semiconductor saturable absorber, a semiconductor light amplifier, a multi-channel array waveguide grate and a phase delay waveguide array that are sequentially connected through a passive ridge waveguide between two cleavage planes. The mode-locked laser can output the femtosecond pulse without using an external pulse compression technology, and has the advantages of simple manufacture process, compact structure, low cost, and mass production.

The invention discloses a small-size frequency doubling green light optical fiber laser. The small-size frequency doubling green light optical fiber laser comprises a semiconductor saturable absorber mirror (SESAM), a pump light stripper, a double-cladding ytterbium-doped optical fiber, a pump combiner, a quasi-phase matching PPLN crystal, a broadband fiber bragg grating and an optical fiber collimator. The PPLN crystal is a waveguide device packaged by a temperature controller. According to the optical fiber laser of a full-waveguide structure, efficient lasers with the bandwidth central wavelength of 532 nm can be obtained based on the intracavity frequency doubling technology. The optical fiber laser is miniaturized, compact in structure, high in stability, high in frequency doubling efficiency and suitable for being applied to the application fields of laser projection machines and the like.

The invention discloses a totally positive dispersion cavity mode-locked all-fiber laser, which is an environmentally-stable, novelly-structured and totally-optical mode-locked super-short laser pulse laser which works in a totally positive dispersion area and uses rare earth-mixed optical fibers as a laser gain medium, a polarization beam splitter to split light, a band-pass long-period fiber grafting filter as a mode-locked laser centre wavelength selection and mode-locked laser spectrum filtering optical pulse compression element, and a semiconductor saturable absorber as a mode-locked element and the like to form an optical fiber laser structure with high repetition rate, high power, simple structure and high efficiency. The laser outputs picosecond and femtosecond optical pulse-width polarized laser with a wavelength of 1 mu m which, after being amplified by the high-power optical fiber amplifier, can be used for molecularly systemic pumping-detection ultrafast optical physical experiment or environment monitoring, microwave photonic or biophysical detection, double-wavelength pumping-detection ultrafast optical physical experiment, frequency-combining optical radiation generation, coherent anti-stokes Raman scattering microscopy, micromachining and the like.