CN206850211U - One kind is based on 1 micron of all -fiber ultrashort pulse laser caused by dispersive wave - Google Patents

Abstract

The utility model discloses a 1-micron all-fiber ultrashort pulse laser generated based on dispersion waves, which belongs to the fields of laser technology, fiber optics and nonlinear optics. The 1 micron all-fiber ultrashort pulse laser includes in the direction of the optical path: pumping and related devices, 1.5 micron fiber mode-locked laser, 1.5 micron fiber optic isolator, fiber combiner, gain fiber, nonlinear fiber, 1 micron band fiber optic isolator. Among them, the 1.5 micron fiber mode-locked laser can adopt a linear cavity structure or a ring cavity structure; the frequency conversion of the 1.5 micron laser can be performed by using the nonlinear effect in the nonlinear fiber to generate a 1 micron band broadband ultrashort pulse laser output. The device has the advantages of simple design, compact structure and cost saving, and can be applied in the fields of biomedicine, environmental monitoring, scientific research and the like.

Description

A 1 micron all-fiber ultrashort pulse laser based on dispersive wave generation

technical field

The utility model discloses a 1-micron all-fiber ultrashort pulse laser generated based on dispersion waves, and belongs to the fields of laser technology, fiber optics and nonlinear optics.

Background technique

Fiber lasers have the advantages of small size, light weight, compact structure, high conversion efficiency, and good output beam quality, and have been developed rapidly in recent years. Ultrashort pulse fiber lasers are gradually being used in material processing, laser medical treatment, The fields of industrial manufacturing, national defense and military, and scientific research have gained more and more users and market share, and have further become the research and development hotspots of various research institutions.

In the current research on 1-micron all-fiber ultrashort pulse lasers, the method of obtaining picosecond or femtosecond ultrashort pulses is mainly passive mode-locking technology, usually by placing a saturable absorber in the laser cavity, using its fast The saturable absorption property induces the self-modulation of light waves, resulting in a pulsed output. According to the difference in the amount of dispersion in the cavity, it can be divided into total positive dispersion dissipative soliton mode-locking and dispersion-managed soliton mode-locking.

In the most commonly used fully positive dispersion dissipative soliton mode-locking technology at present, all components and optical fibers in the resonator have positive dispersion in the 1 micron band, and it is necessary to add a spectral filter in the cavity to provide a dissipation mechanism to obtain a stable mode-locked output. , this method can only generate picosecond pulses, and the femtosecond laser output needs to be compressed outside the cavity to obtain the femtosecond laser output, which is not conducive to the all-fiber design. The dispersion-managed soliton mode-locking technology that introduces negative dispersion fiber into the cavity can directly obtain femtosecond laser output, but currently, fiber devices that can provide negative dispersion in the 1-micron band (such as chirped fiber gratings, bandgap photonic crystal fibers, High-order mode fibers, etc.) are basically dependent on imports and are expensive, which limits the reduction of the production cost of all-fiber ultrashort pulse lasers and is not conducive to the development of industrialization.

With the development of optical fiber nonlinear technology, femtosecond laser output in the 1 micron band can be generated by using 1.5 micron femtosecond laser through frequency conversion. The 1.5-micron band laser has been developed relatively maturely as a communication laser. There are various types of optical fibers in this band, which can be localized and relatively cheap. The 1.5-micron passive mode-locked resonator can directly output femtosecond laser pulses, and then amplify them for use The non-linear optical fiber produces a supercontinuum spectrum to obtain a dispersive wave light source in the 1 micron band, and can directly obtain a femtosecond laser output in the 1 micron band. This method is an all-fiber design, no space components, compact structure, low cost, and no need for imports, which makes the product have better promotion prospects and enhances its industry competitiveness.

Utility model content

In order to solve the problems of difficult direct fiber output femtosecond pulse output, complex compression system, and high cost in the 1-micron band passive mode-locked ultrashort pulse all-fiber laser, the utility model is based on the dispersion wave generation technology and uses a 1.5-micron passive mode-locked fiber laser pump Pu nonlinear optical fiber produces 1 micron ultrashort pulse laser output, and its all-fiber design does not require additional modulation devices and space compression devices, which greatly reduces system complexity and achieves highly integrated and stable ultrashort pulse laser output.

In order to achieve the above object, the utility model adopts the following technical solutions.

A 1-micron all-fiber ultrashort pulse laser based on dispersion wave generation, which consists of a 1.5-micron fiber mode-locked laser, a 1.5-micron fiber amplifier, a nonlinear fiber, a laser output device and other auxiliary devices. The 1.5 micron fiber mode-locked laser includes pump source, fiber combiner or wavelength division multiplexer, gain fiber, laser cavity and saturable absorber. The 1.5 micron fiber amplifier includes a pump source, a fiber combiner or wavelength division multiplexer, and a gain fiber. The nonlinear fiber includes nonlinear fiber; the laser output device includes a fiber isolator or a fiber beam splitter; other auxiliary devices include a spectral filter, a fiber circulator, and a polarization controller.

The pump light generated by the pump source in the 1.5-micron fiber mode-locked laser is coupled into the resonator through a fiber combiner or a wavelength division multiplexer. Under the action of the gain fiber, the continuous laser light is first generated, and then it is absorbed by the saturable absorbing element. The pulsed laser is generated by the action, and then the generated pulsed laser is oscillated and amplified in the resonator, and the 1.5 micron ultrashort pulse laser output is realized through the laser output device. The laser is introduced into the fiber amplifier through the wavelength division multiplexer for further power amplification to increase the average power and peak power, and achieve high-power 1.5 micron ultrashort pulse laser output, and then guide it into the nonlinear optical fiber for frequency conversion to directly obtain 1 micron Ultrashort pulse laser. And output through the laser output device.

A 1-micron all-fiber ultrashort pulse laser based on dispersion waves, characterized in that the 1.5-micron fiber mode-locked laser 1 is connected to the input end of the 1.5-micron fiber isolator 2; the output end of the fiber isolator 2 is connected to the wavelength division multiplexer 4 Signal end, the pump source 3 is connected to the pump end of the wavelength division multiplexer 4; the common end of the wavelength division multiplexer 4 is connected to the gain fiber 5 for power amplification; the other end of the gain fiber 5 is connected to the nonlinear fiber 6; the output of the nonlinear fiber 6 The end is connected to the input end of the 1-micron fiber isolator; the input end of the 1-micron fiber isolator is used for laser output.

The 1.5 micron fiber mode-locked laser can be classified into fiber lasers with linear cavity or ring cavity structure.

1.5 micron line cavity mode-locked fiber laser is characterized in that the pumping source 111 is connected to the pumping end of the wavelength division multiplexer 112; the common end of the wavelength division multiplexer 112 is connected to the gain fiber 113; the gain fiber 113 is another One end is connected to the saturable absorber 114; the laser light reflected by the saturable absorber 114 reaches the signal end of the wavelength division multiplexer after passing through the common end of the gain fiber and the wavelength division multiplexer, and is connected with the reflective fiber Bragg grating 115; the reflective fiber Bragg grating The other end of the grating 115 is connected to a 1.5 micron fiber isolator 116 for laser output.

A 1.5-micron ring cavity mode-locked fiber laser is characterized in that the pump source 111 is connected to the pump end of the wavelength division multiplexer 112; the common end of the wavelength division multiplexer 112 is connected to the gain fiber 113; the other end of the gain fiber It is connected to the common end of the optical fiber splitter 117, and the splitting end 1 of the optical fiber splitter is used as the laser output port; the splitting end 2 of the optical fiber splitter is connected to the port A of the optical fiber circulator 119; the light comes out from the port B of the circulator After being reflected by the saturable absorber 114, it returns to the circulator port B and reaches the circulator port C; the circulator port C is connected to the spectral filter 121; the other end of the spectral filter 121 is connected to the signal end of the wavelength division multiplexer 112 to form a ring resonant cavity.

The reflective fiber Bragg grating 115 in the 1.5 micron line cavity mode-locked fiber laser can also be replaced by a total reflection mirror 118 to form a resonant cavity, and a fiber beam splitter 117 and a fiber isolator 116 are added in the resonant cavity as laser output devices .

The fiber circulator 119 and the saturable absorber 114 in the 1.5 micron ring cavity mode-locked fiber laser can be replaced with a pair of polarization controllers 120, 122 and a polarization-sensitive isolator 116 for mode-locking.

The reflective fiber Bragg grating in the linear resonator structure is a diffraction grating formed by periodically modulating the refractive index of the fiber core in the axial direction through a certain method, and its reflectivity R and reflection wavelength can be customized according to needs, wherein 0<R<1.

The pumping source is a semiconductor laser, a solid laser, a gas laser, a fiber laser or a Raman laser, and the central wavelength of the output pumping light ranges from 700nm to 1000nm.

The gain fiber is an optical fiber or photonic crystal fiber doped with rare earth elements, wherein the doped rare earth elements are ytterbium (Yb), neodymium (Nd), erbium (Er), thulium (Tm), holmium (Ho), samarium ( One or more of Sm), bismuth (Bi).

The nonlinear optical fiber is one of heavy metal ion-doped oxide glass optical fiber or optical crystal optical fiber.

The saturable absorber is one or more of semiconductor saturable absorber mirrors, graphene, graphene oxide, carbon nanotubes, and topological insulators.

The pumping method is fiber core single-end pumping, fiber core double-end pumping, cladding single-end pumping or cladding double-end pumping.

The optical fiber beam combiner is one of a polarized light beam combiner or a non-polarized light beam combiner. The optical fiber combiner can also be replaced with a wavelength division multiplexer;

The splitting ratio of the optical fiber splitter is between 0 and 1.

The filter is a fused cone fiber filter, a Fabry-Perot filter, a multilayer dielectric film filter, a Mach-Zehnder interference filter, a volume grating filter, an arrayed waveguide grating filter (AWG), a fiber grating filter One of the acousto-optic tunable filters.

Compared with the prior art, the utility model has the following beneficial effects.

1. The utility model uses a 1.5-micron fiber laser to perform frequency conversion in a nonlinear optical fiber to directly generate an ultrashort pulse laser output in a 1-micron band.

2. The utility model does not need to use 1 micron band dispersion management optical fiber, and all use 1.5 micron band commercial optical fiber, which has complete types of optical fibers, low cost, and is easy to industrialize.

3. The utility model adopts the all-fiber structure design and can directly generate 1 micron ultrashort pulse laser output without external additional pulse compressor, with simple design and compact structure.

Description of drawings

Fig. 1 is a schematic diagram of the basic principles of the 1 micron all-fiber ultrashort pulse laser based on the generation of dispersive waves in Embodiment 1.

Fig. 2 is a structural diagram of embodiment 2 when the resonant cavity is a linear structure.

Fig. 3 is a structural diagram of embodiment 3 when the resonant cavity is a linear structure.

Fig. 4 is a structural diagram of embodiment 4 when the resonant cavity is a ring structure.

Fig. 5 is a structural diagram of embodiment 5 when the resonant cavity is a ring structure.

In the figure: 1. 1.5 micron mode-locked fiber laser, 2. Fiber isolator, 3. Pump source, 4. Wavelength division multiplexer, 5. Gain fiber, 6. Nonlinear fiber, 7. Fiber isolator, 111 , pump source, 112, wavelength division multiplexer, 113, gain fiber, 114, saturable absorber, 115, reflective fiber Bragg grating, 116, optical fiber isolator, 117, optical beam splitter, 118, total reflection Mirror, 119, fiber optic circulator, 120, first polarization controller, 121, spectral filter, 122, second polarization controller.

detailed description

The utility model will be described in further detail below in conjunction with illustrations 1-5, but not limited to the following examples.

Example 1

A 1 micron all-fiber ultrashort pulse laser based on dispersive wave generation is shown in Figure 1. The 1.5-micron mode-locked fiber laser 1 in the figure is designed with an all-fiber structure, using linear cavity or ring cavity passive mode-locking technology to obtain 1.5-micron ultrashort pulse laser output; then connected to a 1.5-micron fiber isolator 2, whose function is to prevent light return Reflection, improve output power stability, connect the output light to the signal end of the wavelength division multiplexer 4, the pump end of the wavelength division multiplexer 4 can be connected to the semiconductor laser diode pump source 3 with a center wavelength of 976nm, and the wavelength division multiplexer Use the common end of the device 4 to connect a section of 1m-long single-clad erbium-doped fiber 5 for power amplification; the output end of the erbium-doped fiber is directly fused with the nonlinear fiber 6, and the nonlinear effect is used for frequency conversion to generate ultrashort pulse laser in the 1 micron band output, and then connect the 1 micron fiber optic isolator 7 to prevent back light reflection and improve output power stability.

Example 2

The structural diagram when the resonant cavity is a linear structure is shown in Figure 2. Among the figure, pumping source 111 can select the semiconductor laser diode that central wavelength is 976nm for use; It is connected with the pumping end of wavelength division multiplexer 112, provides pumping light for the laser; The erbium fiber 113 is connected to provide gain for the laser; the saturable absorber 114 is a key device for generating mode-locked pulses, and semiconductor saturable absorber mirrors, graphene, graphene oxide, carbon nanotubes or topological insulators can be selected; wavelength division multiplexer The signal end of 112 is connected to the reflective fiber Bragg grating 115, which acts as a cavity mirror and also defines the wavelength of the resonator; then connects a 1.5-micron fiber isolator 116 to prevent back-light reflection and improve output power stability.

Example 3

The structural diagram when the resonant cavity is a linear structure is shown in Figure 3. Among the figure, pumping source 111 can select the semiconductor laser diode that central wavelength is 976nm for use; It is connected with the pumping end of wavelength division multiplexer 112, provides pumping light for the laser; The erbium fiber 113 is connected to provide gain for the laser; the saturable absorber 114 is a key device for generating mode-locked pulses, and semiconductor saturable absorber mirrors, graphene, graphene oxide, carbon nanotubes or topological insulators can be selected; wavelength division multiplexer The signal end of 112 is connected to the common end of the optical fiber beam splitter 117 as an intracavity output device, and the beam splitting end 1 of the optical fiber beam splitter 117 is connected to the bandpass total reflection mirror 118 as a cavity mirror while defining the wavelength of the resonant cavity ; Fiber splitter 117 beam splitter end 2 is connected to 1.5 micron fiber isolator 116, play a role in preventing back light reflection and improving output power stability.

Example 4

The structural diagram when the resonant cavity is a ring structure is shown in Fig. 4 . Among the figure, pumping source 111 can select the semiconductor laser diode that central wavelength is 976nm for use; It is connected with the pumping end of wavelength division multiplexer 112, provides pumping light for the laser; The erbium fiber 113 is connected to provide gain for the laser; the erbium-doped fiber is connected to the common end of the fiber beam splitter 117, and the beam splitter 1 of the fiber beam splitter is used as the laser output port, and the beam splitter 2 is connected to the port A of the optical fiber circulator 119, The light coming out of the circulator port B is reflected by the saturable absorber 114 and returns to the circulator port B to reach the circulator port C. The saturable absorber 114 is the key device for generating the mode-locked pulse, and a semiconductor saturable absorber mirror can be selected , graphene, graphene oxide, carbon nanotubes or topological insulators; the circulator port C is connected to the spectral filter 121 to define the wavelength of the resonant cavity; the output light is connected to the signal end of the wavelength division multiplexer 112 to form a ring resonant cavity.

Example 5

The structural diagram when the resonant cavity is a ring structure is shown in Fig. 5 . Among the figure, pumping source 111 can select the semiconductor laser diode that central wavelength is 976nm for use; It is connected with the pumping end of wavelength division multiplexer 112, provides pumping light for the laser; The erbium fiber 113 is connected to provide gain for the laser; the erbium-doped fiber is connected to the common end of the fiber beam splitter 117, and the beam splitter 1 of the fiber beam splitter is used as the laser output port, and the beam splitter 2 is connected to a pair of polarization controllers 120,122. A polarization-sensitive isolator 116 is added between the two polarization controllers, and the two polarization controllers and the polarization-sensitive isolator together function as saturable absorbers for generating mode-locked pulse output. The output light enters the spectral filter 121 for wavelength selection and stable output wavelength. The output terminal of the spectral filter 121 is connected with the signal terminal of the wavelength division multiplexer to form a ring resonant cavity.

Claims (10)

1. A 1 micron all-fiber ultrashort pulse laser based on dispersion wave generation, characterized in that: the laser comprises a 1.5 micron fiber mode-locked laser, a 1.5 micron fiber amplifier, a nonlinear optical fiber, and a laser output device; wherein the 1.5 micron fiber lock Mode lasers include pump sources, fiber combiners or wavelength division multiplexers, gain fibers, laser resonators and saturable absorbers; 1.5 micron fiber amplifiers include pump sources, fiber combiners or wavelength division multiplexers, Gain fiber; the laser output device includes a fiber isolator or a fiber splitter; The pump light generated by the pump source in the 1.5-micron fiber mode-locked laser is coupled into the resonator through a fiber combiner or a wavelength division multiplexer. Under the action of the gain fiber, the continuous laser light is first generated, and then it is absorbed by the saturable absorbing element. The pulsed laser is generated by the action, and then the generated pulsed laser is oscillated and amplified in the resonator, and the 1.5 micron ultrashort pulse laser output is realized through the laser output device; the laser is introduced into the fiber amplifier through a wavelength division multiplexer for further power amplification to improve the average Power and peak power, to achieve higher power 1.5 micron ultrashort pulse laser output, and then guide it into a nonlinear optical fiber for frequency conversion to directly obtain 1 micron ultrashort pulse laser; and output through the laser output device. 2. a kind of 1 micron all-fiber ultrashort pulse laser that produces based on dispersion wave according to claim 1, is characterized in that, described gain fiber is the optical fiber or the photonic crystal fiber doped with rare earth element, wherein the doped rare earth The element is one or more of ytterbium, neodymium, erbium, thulium, holmium, samarium, and bismuth; the nonlinear fiber is one of heavy metal ion-doped oxide glass fiber or optical crystal fiber; the saturable absorption The body is one or more of semiconductor saturable absorbing mirrors, graphene, graphene oxide, carbon nanotubes, and topological insulators. 3. a kind of 1 micron all-fiber ultrashort pulse laser that produces based on dispersion wave according to claim 1, is characterized in that, described pumping mode is fiber core single-ended pumping, fiber core double-ended pumping, wrapping Layer single-ended pumping or cladding double-ended pumping; the fiber beam combiner is a polarized beam combiner or a non-polarized beam combiner; the splitting ratio of the fiber beam splitter is between 0 and 1 between. 4. a kind of 1 micron all-fiber ultrashort pulse laser that produces based on dispersion wave according to claim 1, is characterized in that, described pumping source is semiconductor laser, solid laser, gas laser, fiber laser or Raman laser , the range of the central wavelength of the output pump light is: 700nm-2000nm. 5. A 1 micron all-fiber ultrashort pulse laser based on dispersion wave generation, characterized in that the 1.5 micron fiber mode-locked laser (1) is connected to the 1.5 micron fiber isolator (2) input; the fiber isolator (2) output The end is connected to the signal end of the wavelength division multiplexer (4), and the pump source (3) is connected to the pump end of the wavelength division multiplexer (4); the common end of the wavelength division multiplexer (4) is connected to one end of the gain fiber (5) Power amplification is performed; the other end of the gain fiber (5) is connected to the nonlinear fiber (6); the output end of the nonlinear fiber is connected to the input end of the 1-micron fiber isolator; the input end of the 1-micron fiber isolator is used for laser output. 6. a kind of 1 micron all-fiber ultrashort pulse laser that produces based on dispersion wave according to claim 5 is characterized in that, described pumping source is semiconductor laser, solid laser, gas laser, fiber laser or Raman laser , the range of the central wavelength of the output pump light is: 700nm-2000nm. 7. A kind of 1-micron all-fiber ultrashort pulse laser based on dispersion wave generation according to claim 5, characterized in that, in the 1.5-micron line cavity mode-locked fiber laser, the reflective fiber Bragg grating is formed by a total reflection mirror Instead of forming a resonant cavity, a fiber beam splitter and a fiber isolator are added in the resonant cavity as a laser output device. 8. A kind of 1 micron all-fiber ultrashort pulse laser that produces based on dispersion wave according to claim 7, is characterized in that, in the resonant cavity structure, reflective fiber Bragg grating is a kind of refraction of the fiber core by a certain method. The diffraction grating is formed by axial periodic modulation of the rate, and its reflectivity R and reflection wavelength can be customized as required, where 0<R<1. 9. A 1-micron all-fiber ultrashort pulse laser based on dispersion waves, characterized in that the 1.5-micron fiber mode-locked laser is divided into fiber lasers with linear cavity or ring cavity structure; 1.5 micron line cavity mode-locked fiber laser, the pump source is connected to the pump end of the wavelength division multiplexer; the common end of the wavelength division multiplexer is connected to one end of the gain fiber; the other end of the gain fiber is connected to a saturable absorber ; The laser reflected by the saturable absorber passes through the common end of the gain fiber and the wavelength division multiplexer, then reaches the signal end of the wavelength division multiplexer and connects with one end of the reflective fiber Bragg grating; the other end of the reflective fiber Bragg grating is isolated from the 1.5 micron optical fiber The device is connected for laser output; 1.5 micron ring cavity mode-locked fiber laser, the pump source is connected to the pump end of the wavelength division multiplexer; the common end of the wavelength division multiplexer is connected to one end of the gain fiber; the other end of the gain fiber is common to the fiber splitter One end of the fiber splitter is used as the laser output port; the other end of the fiber splitter is connected to the port A of the fiber circulator; the light comes out from the port B of the circulator and is reflected by a saturable absorber Return to circulator port B and reach circulator port C; circulator port C is connected to one end of the spectral filter; the other end of the spectral filter is connected to the signal end of the wavelength division multiplexer 112 to form a ring resonant cavity. 10. A kind of 1 micron all-fiber ultrashort pulse laser based on dispersion wave generation according to claim 9, characterized in that, the fiber circulator and saturable absorber in the 1.5 micron ring cavity mode-locked fiber laser are replaced Mode-locks a pair of polarization controllers and polarization-sensitive isolators.