Seed source device and laser system

Abstract

The invention discloses a seed source device and a laser system, in the seed source device provided by the invention, first signal light is transmitted in a first optical fiber, and second signal light is transmitted in the first optical fiber and a second optical fiber; and the nonlinear phase shift generated by the first signal light in the first optical fiber is different from the nonlinear phase shift generated by the second signal light in the first optical fiber and the second optical fiber. The first optical fiber is arranged to transmit the first signal light and the second signal light, and the second optical fiber is arranged to transmit the second signal light, so that the propagation paths of the first signal light and the second signal light are different, different nonlinear phase shifts are generated, the saturable absorption effect can be generated in the polarization-maintaining optical fiber coupler, and ultra-short pulses are generated. A phase shifter with a space structure does not need to be additionally arranged, the arrangement space is reduced, manufacturing is easy, the anti-interference capacity is high, cost is low, large-scale production and application are easier, and the use experience of a user for the seed source device is improved.

Description

Technical Field

[0001] The present application relates to the field of laser technology, and in particular to a seed source device and a laser system. Background Art

[0002] Ultrashort pulses are mainly generated through active and passive mode-locking technologies. Mode-locking is achieved by adjusting the state in the cavity so that each independent longitudinal mode has a fixed phase relationship, and coherent superposition forms a periodic pulse sequence. Therefore, mode-locking is also called phase-locking. The commonly used mode-locking method for active mode-locked lasers is through acousto-optic or electro-optic debugging, which is generally in the ps (picosecond) level. It has the disadvantages of large size, complex system, high cost, and large pulse width, making it difficult to achieve laser cold processing.

[0003] Passive mode locking mainly uses the saturable absorption effect of natural or artificial saturable absorbers to produce ultrashort pulses. The mainstream industrial fully polarization-maintaining ultrashort pulse fiber laser seed source mainly uses natural saturable absorbers, such as semiconductor saturable absorber mirrors (SESAM) to achieve mode locking. Compared with artificial saturable absorbers, SESAM mode locking has low difficulty in self-starting and mature technology routes, but has long recovery time, low damage threshold, short service life, low signal-to-noise ratio, and high price. Compared with natural saturable absorbers, artificial saturable absorbers have the characteristics of low noise and short recovery time, and can produce shorter pulses. However, the mode locking technology using artificial saturable absorbers requires large nonlinear phase shift of the signal light, high threshold of self-starting mode locking, and high technical level requirements. Summary of the invention

[0004] In order to solve the above technical problems, the present application provides a seed source device, including a pump source, a polarization-maintaining fiber combiner and a polarization-maintaining fiber coupler;

[0005] The pump source is connected to the polarization-maintaining fiber combiner to generate pump light and transmit the pump light to the polarization-maintaining fiber combiner; the first output end of the polarization-maintaining fiber combiner is connected to the polarization-maintaining fiber coupler through a first optical fiber to transmit a first signal light and a second signal light to the polarization-maintaining fiber coupler, and the second output end of the polarization-maintaining fiber combiner is connected to the polarization-maintaining fiber coupler through a second optical fiber to transmit the second signal light; the polarization-maintaining fiber coupler is used to couple the first signal light and the second signal light;

[0006] The nonlinear phase shift generated by the first signal light in the first optical fiber is different from the nonlinear phase shift generated by the second signal light in the first optical fiber and the second optical fiber.

[0007] Wherein, the first optical fiber is a polarization-maintaining active optical fiber.

[0008] Wherein, the seed source device further includes a grating component, and the grating component is connected to the polarization-maintaining fiber coupler, and is used to receive the signal light coupled by the polarization-maintaining fiber coupler, and process the signal light.

[0009] Wherein, the grating component includes a chirped fiber Bragg grating.

[0010] Wherein, the polarization-maintaining active optical fiber is a double-clad optical fiber.

[0011] Wherein, the double-clad optical fiber comprises a core, an inner cladding and an outer cladding, wherein the inner cladding is sleeved on the core, and the outer cladding is sleeved on the inner cladding;

[0012] Wherein, the central axis of the inner cladding is staggered with the core.

[0013] Wherein, the double-clad optical fiber comprises a core, an inner cladding and an outer cladding, wherein the inner cladding is sleeved on the core, and the outer cladding is sleeved on the inner cladding;

[0014] Wherein, the radial cross-sectional shape of the inner cladding is one of an ellipse, a D-shape and a triangle.

[0015] Wherein, a propagation direction of the first signal light is opposite to a propagation direction of the second signal light.

[0016] Wherein, the pump source is a multi-mode laser.

[0017] In order to solve the above technical problems, the present application also provides a laser system, comprising the seed source device as described above, wherein the seed source device is used to generate ultrashort pulse laser.

[0018] Beneficial effects of the present application: Different from the prior art, the seed source device provided by the present application includes a pump source, a polarization-maintaining fiber combiner and a polarization-maintaining fiber coupler. The pump source is connected to the polarization-maintaining fiber combiner to generate pump light and transmit the pump light to the polarization-maintaining fiber combiner. The first output end of the polarization-maintaining fiber combiner is connected to the polarization-maintaining fiber coupler through a first optical fiber to transmit the first signal light and the second signal light to the polarization-maintaining fiber coupler. The second output end of the polarization-maintaining fiber combiner is connected to the polarization-maintaining fiber coupler through a second optical fiber to transmit the second signal light. The polarization-maintaining fiber coupler is used to couple the first signal light and the second signal light. The nonlinear phase shift generated by the first signal light in the first optical fiber and the nonlinear phase shift generated by the second signal light in the first optical fiber and the second optical fiber are different. By setting a first optical fiber to transmit the first signal light and the second signal light, and a second optical fiber to transmit the second signal light, the first signal light and the second signal light produce different nonlinear phase shifts, thereby achieving a saturable absorption effect to produce ultrashort pulses. There is no need to additionally set up a phase shifter with a spatial structure, thus reducing the setting space, making it simple to manufacture, having strong anti-interference ability, and low cost, making it easier to mass produce and apply, and improving the user experience of the seed source device. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0020] in:

[0021] Figure 1 It is a structural schematic diagram of an embodiment of a seed source device of the present application.

[0022] Reference numerals: seed source device A; pump source 1; polarization-maintaining fiber combiner 2; polarization-maintaining fiber coupler 3; polarization-maintaining active fiber 4; grating assembly 5. DETAILED DESCRIPTION

[0023] The scheme of the embodiment of the present application is described in detail below in conjunction with the drawings of the specification.

[0024] In the following description, for the purpose of explanation rather than limitation, specific details such as specific system structures, interfaces, and technologies are provided to facilitate a thorough understanding of the present application.

[0025] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0026] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the objects associated before and after are in an "or" relationship. In addition, "many" in this article means two or more than two. In addition, the term "at least one" in this article means any combination of at least two of any one or more of a plurality of, for example, including at least one of A, B, and C, and can mean including any one or more elements selected from the set consisting of A, B, and C. In addition, the terms "first", "second", and "third" in this application are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features.

[0027] The present application provides a seed source device, including a pump source, a polarization-maintaining fiber combiner, and a polarization-maintaining fiber coupler;

[0028] The pump source is connected to the polarization-maintaining fiber combiner to generate pump light and transmit the pump light to the polarization-maintaining fiber combiner; the first output end of the polarization-maintaining fiber combiner is connected to the polarization-maintaining fiber coupler through a first optical fiber to transmit a first signal light and a second signal light to the polarization-maintaining fiber coupler, and the second output end of the polarization-maintaining fiber combiner is connected to the polarization-maintaining fiber coupler through a second optical fiber to transmit the second signal light; the polarization-maintaining fiber coupler is used to couple the first signal light and the second signal light;

[0029] The nonlinear phase shift generated by the first signal light in the first optical fiber is different from the nonlinear phase shift generated by the second signal light in the first optical fiber and the second optical fiber.

[0030] Optionally, in some embodiments, the first optical fiber is a polarization-maintaining active optical fiber.

[0031] Optionally, in some embodiments, the seed source device further includes a grating component, and the grating component is connected to the polarization-maintaining fiber coupler, and is used to receive the signal light coupled by the polarization-maintaining fiber coupler, and process the signal light.

[0032] Optionally, in some embodiments, the grating assembly comprises a chirped fiber Bragg grating.

[0033] Optionally, in some embodiments, the polarization-maintaining active optical fiber is a double-clad optical fiber.

[0034] Optionally, in some embodiments, the double-clad optical fiber comprises a core, an inner cladding and an outer cladding, wherein the inner cladding is sleeved on the core, and the outer cladding is sleeved on the inner cladding;

[0035] Wherein, the central axis of the inner cladding is staggered with the core.

[0036] Optionally, in some embodiments, the double-clad optical fiber comprises a core, an inner cladding and an outer cladding, wherein the inner cladding is sleeved on the core, and the outer cladding is sleeved on the inner cladding;

[0037] Wherein, the radial cross-sectional shape of the inner cladding is one of an ellipse, a D-shape and a triangle.

[0038] Optionally, in some embodiments, a propagation direction of the first signal light is opposite to a propagation direction of the second signal light.

[0039] Optionally, in some embodiments, the pump source is a multi-mode laser.

[0040] The present application also provides a laser system, comprising the seed source device as described above, wherein the seed source device is used to generate ultrashort pulse laser.

[0041] The following is a description of the contents of the embodiments of the present application in conjunction with the accompanying drawings:

[0042] In the prior art, artificial saturable absorbers mainly include nonlinear polarization rotation (NPR), nonlinear optical loop mirror (NOLM), and nonlinear amplification fiber loop mirror (NALM).

[0043] Among them, NPR has a particularly high requirement for the precision of the welding angle in the production process of the fully polarization-maintaining seed source, which makes it difficult to replicate and produce in batches. Both NOLM and NALM locking technologies use a loop mirror (LM) to form a Sagnac interferometer. After two lights with opposite transmission directions experience different degrees of nonlinear phase shift, a saturable absorption effect is formed. Without considering the gain, the transmittance function is α represents the beam splitting ratio, It is the additional phase shift in LM transmission. Two lights with opposite transmission directions are coherently superimposed in the polarization-maintaining fiber coupler. The transmittance is also related to the coupling ratio, nonlinear phase shift, refractive index difference between fast and slow axes, and polarization angle of the polarization-maintaining fiber coupler. The larger the coupling ratio, the lower the modulation depth, the weaker the filtering effect, and the easier it is to self-start. When the coupling ratio is closer to 50:50, the modulation depth is greater, the filtering effect is the strongest, and the difficulty of self-start is the greatest. NOLM and NALM require large nonlinear phase shift, high threshold of mode-locking self-starting, and industrial seed sources require high repetition rate, which requires high technical level.

[0044] In order to solve the above technical problems, this application proposes a seed source device, please refer to Figure 1 , Figure 1 The seed source device A provided in the present application uses NALM mode locking technology, including a pump source 1, a polarization-maintaining fiber combiner 2 and a polarization-maintaining fiber coupler 3.

[0045] Among them, the pump source 1 is connected to the polarization-maintaining fiber combiner 2, which is used to generate pump light and transmit the pump light to the polarization-maintaining fiber combiner 2. The first output end of the polarization-maintaining fiber combiner 2 is connected to the polarization-maintaining fiber coupler 3 through the first optical fiber to transmit the first signal light and the second signal light to the polarization-maintaining fiber coupler 3. The second output end of the polarization-maintaining fiber combiner 2 is connected to the polarization-maintaining fiber coupler 3 through the second optical fiber to transmit the second signal light. The polarization-maintaining fiber combiner 2 is used to couple the pump light into the first optical fiber.

[0046] Specifically, after the polarization-maintaining fiber combiner 2 receives the pump light, the polarization-maintaining fiber combiner 2 is used to couple the pump light into the first optical fiber. The pump light is used to inject energy into the first optical fiber so that the dopant in the first optical fiber absorbs the energy and excites, thereby emitting more photons, and finally enhancing the intensity of the optical signal. Then, the first optical fiber and the pump light act to generate a first signal light and a second signal light with opposite propagation directions, and the first signal light and the second signal light are transmitted to the polarization-maintaining fiber coupler 3 via the first optical fiber.

[0047] Furthermore, since the second signal light is also transmitted from the polarization-maintaining fiber coupler 3 to the polarization-maintaining fiber combiner 2 through the second optical fiber, and then transmitted from the polarization-maintaining fiber combiner 2 to the polarization-maintaining fiber coupler 3 through the first optical fiber, the first signal light in the opposite direction of propagation to the second signal light stays in the polarization-maintaining fiber coupler 3 after being transmitted to the polarization-maintaining fiber coupler 3 by the first optical fiber for the first time. Therefore, the propagation paths of the first signal light and the second signal light in the optical fiber are different, and the first signal light can generate a first nonlinear phase shift when it is transmitted in the first optical fiber, and the second signal light can generate a second nonlinear phase shift when it is transmitted in the first optical fiber and the second optical fiber, and the first nonlinear phase shift and the second nonlinear phase shift are different.

[0048] In one embodiment, the different nonlinear phase shifts of the first signal light and the second signal light are also related to the different splitting ratios of the polarization-maintaining fiber combiner 2 and the different amplification powers of the first optical fiber to the first signal light and the second signal light.

[0049] After the polarization-maintaining fiber coupler 3 receives the first signal light and the second signal light with different nonlinear phase shifts, the first signal light and the second signal light can be coherently combined in the cone region of the polarization-maintaining fiber coupler 3 to produce a saturable absorption effect and realize NALM mode locking.

[0050] In summary, by setting the first optical fiber to transmit the first signal light and the second signal light, and the second optical fiber to transmit the second signal light, the propagation paths of the first signal light and the second signal light are different, and different nonlinear phase shifts are generated, so that the saturable absorption effect can be realized in the polarization-maintaining fiber coupler 3, and the NALM mode-locked self-starting can be realized to generate ultra-short pulses. There is no need to additionally set up a phase shifter with a spatial structure, which reduces the setting space, is simple to manufacture, has strong anti-interference ability, low cost, long life, low pulse noise, high pulse repetition frequency, is easier to mass produce and apply, and improves the user experience of the seed source device.

[0051] Optionally, the first optical fiber is a polarization-maintaining active optical fiber 4 .

[0052] Among them, the polarization-maintaining active optical fiber 4 has the characteristics of high bandwidth, low latency, scalability, high reliability and anti-electromagnetic interference capability. The pump light can pump the low-energy-level electrons in the polarization-maintaining active optical fiber 4 to the high-energy level, generating a large number of upper-energy-level particles, and then generating the first signal light and the second signal light with opposite propagation directions in the first optical fiber, thereby improving the reliability and practicality of the seed source device A.

[0053] The second optical fiber may be a common passive optical fiber, a highly nonlinear optical fiber, or other types of optical fibers, etc. On the basis of achieving the propagation of the second signal light, the present application does not impose any specific limitation on this.

[0054] Among them, the polarization-maintaining fiber combiner 2, the polarization-maintaining active fiber 4, the second optical fiber and the polarization-maintaining fiber coupler 3 form the ring mirror (LM) mentioned above, and then after the polarization-maintaining fiber coupler 3 receives the first signal light and the second signal light with opposite propagation directions and different nonlinear phase shifts, the first signal light and the second signal light can be coherently combined in the cone region of the polarization-maintaining fiber coupler 3 to produce a saturable absorption effect, realize NALM mode-locked self-start, generate ultrashort pulse laser, and improve the practicality and operation efficiency of the seed source device A.

[0055] In one embodiment, the seed source device A further includes a grating component 5, which is connected to the polarization-maintaining fiber coupler 3 and is used to receive the signal light coupled by the polarization-maintaining fiber coupler 3 and process the signal light.

[0056] Specifically, after the polarization-maintaining fiber coupler 3 couples the first signal light and the second signal light, the generated signal light is an ultrashort pulse laser. The grating component 5 can modulate the pulse width of the ultrashort pulse through its diffraction and interference effects. When the ultrashort pulse passes through the grating component 5, components of different wavelengths will diffract at different angles, causing the pulse to be stretched in time. By adjusting the parameters of the grating and the angle of the incident light, the stretching degree of the pulse can be accurately controlled, and then the dispersion of the signal light can be managed to generate laser pulses of different pulse widths and types, thereby increasing the application range of the seed source device A.

[0057] After the grating component 5 processes the signal light, the processed signal light can be output, so that the laser device can operate using the processed signal light.

[0058] In other embodiments, after the polarization-maintaining fiber coupler 3 couples the first signal light and the second signal light, the laser device may be directly connected to the polarization-maintaining fiber coupler 3, and the polarization-maintaining fiber coupler 3 directly outputs the coupled signal light.

[0059] Optionally, the grating component 5 includes a chirped fiber Bragg grating.

[0060] Among them, the chirped fiber Bragg grating is an excellent dispersion management device. It has the characteristics of small size, large compensation, low insertion loss, and good fiber compatibility. It is widely used in important fields such as fiber laser, fiber communication, and fiber sensing. As a non-uniform grating, the main feature of the chirped fiber Bragg grating is that the refractive index modulation period and amplitude of the core change in a certain regularity along the axial direction of the optical fiber. From a structural point of view, it can be regarded as an orderly combination of multiple uniform gratings with different periods. Normally, when a light pulse is transmitted in a fiber grating, Bragg reflection will be generated at a specific wavelength due to the mode coupling effect of the optical waveguide. The wavelength is linearly related to the period of the grating. Since the period of each segment of the chirped fiber Bragg grating is different, the corresponding Bragg wavelength will also change, resulting in a larger reflection spectrum width. At the same time, a certain pulse delay will be generated with the introduction of the optical path difference.

[0061] Therefore, this embodiment can use a linear chirped fiber Bragg grating to perform online dispersion compensation, broaden the ultrashort pulse, and improve the practicality and reliability of the seed source device A.

[0062] Optionally, the polarization-maintaining active optical fiber 4 is a double-clad optical fiber.

[0063] In a double-clad optical fiber, the pump light and the signal light can be conducted in different media in the optical fiber. Specifically, the double-clad optical fiber includes a core, an inner cladding and an outer cladding, wherein the inner cladding is sleeved on the core and the outer cladding is sleeved on the inner cladding. The core can be the dopant described above, which can be particles of different concentrations and types. The signal light generated after being excited by the pump light can be conducted in the optical fiber, while the pump light is restricted by the outer cladding with a lower refractive index to propagate in the inner cladding, and can be absorbed by the ions in the core to generate signal light.

[0064] Specifically, the inner cladding has a larger area than the core and usually has a larger numerical aperture, which can support more propagation modes, effectively couple light, and transmit higher power. This allows for cheaper, higher-power multimode lasers (LDs) to be pumped, resulting in higher laser power, making it easier to meet the mode-locking self-starting threshold, improving the reliability and practicality of the seed source device A, while reducing the manufacturing cost of the seed source device A and improving the user experience of the seed source.

[0065] In one embodiment, the double-clad optical fiber is an asymmetric structure to increase the overlap between the pump light and the core and to increase the excitation effect of the pump light on the core. In practical applications, if the double-clad optical fiber is a symmetrical structure, there is a hole in the core region of the pump light intensity distribution. The pump light is not completely absorbed, which will reduce the excitation effect of the pump light on the core, and further affect the quality of the first signal light and the second signal light, resulting in low coupling efficiency of the polarization-maintaining optical fiber coupler 3. In this embodiment, the double-clad optical fiber is set to an asymmetric structure to increase the overlap between the pump light and the core, increase the excitation effect of the pump light on the core, and improve the quality of the first signal light and the second signal light, thereby improving the operating efficiency of the seed source device A.

[0066] The asymmetric structure of the double-clad optical fiber does not mean that the radial cross-section of the double-clad optical fiber is an asymmetric shape, but that the thickness of the inner cladding corresponding to each point on the circumference of the core of the double-clad optical fiber is different.

[0067] Optionally, the asymmetric structure of the double-clad optical fiber can be such that the central axis of the inner cladding is staggered from the core, that is, the core is not arranged at the central axis of the double-clad optical fiber, so as to achieve different thicknesses of the inner cladding corresponding to various points on the circumference of the core in the double-clad optical fiber, so as to increase the degree of overlap between the pump light and the core, increase the excitation effect of the pump light on the core, improve the quality of the first signal light and the second signal light, and thereby improve the operating efficiency of the seed source device A.

[0068] Optionally, the asymmetric structure of the double-clad optical fiber can also be one of the radial cross-sectional shapes of the inner cladding, such as an ellipse, a D shape, and a triangle, wherein when the radial cross-sectional shape of the inner cladding is an ellipse, etc., the thickness of the inner cladding corresponding to each point in the circumference of the core is different, so as to improve the overlap degree of the pump light and the core, improve the excitation effect of the pump light on the core, improve the quality of the first signal light and the second signal light, and thus improve the operation efficiency of the seed source device A. In other embodiments, the radial cross-sectional shape of the inner cladding can also be other specific shapes, and the present application does not limit this on the basis of realizing the double-clad optical fiber as an asymmetric structure.

[0069] In one embodiment, the pump source 1 may be a multi-mode laser (LD).

[0070] Among them, the energy of the pump light generated by the multi-mode laser is relatively uniform, and the pump power is high and the cost is low. As mentioned above, the polarization-maintaining active optical fiber 4 is a double-clad optical fiber, which has a high transmission power for the signal light and allows the connection of the multi-mode laser. Among them, since the polarization-maintaining active optical fiber 4 has a high transmission power and the multi-mode laser has a high pump power, the quality of the first signal light and the second signal light can be improved, and it is easier to meet the locking mode self-starting threshold, improve the operating efficiency of the seed source device A, and improve the reliability and practicality of the seed source device A. At the same time, the manufacturing cost of the seed source device A is reduced, and the user's experience of using the seed source is improved.

[0071] In summary, in the seed source device A provided by the present application, by setting a first optical fiber to transmit the first signal light and the second signal light, and a second optical fiber to transmit the second signal light, the propagation paths of the first signal light and the second signal light are different, and different nonlinear phase shifts are generated, so that the saturable absorption effect can be realized in the polarization-maintaining fiber coupler 3, and the NALM mode-locked self-starting can be realized to generate ultra-short pulses. There is no need to additionally set up a phase shifter with a spatial structure, which reduces the setting space, has simple production, strong anti-interference ability, low cost, long life, low pulse noise, high pulse repetition frequency, is easier to mass produce and apply, and improves the user experience of the seed source device.

[0072] At the same time, since the polarization-maintaining fiber combiner 2 and the polarization-maintaining fiber coupler 3 are connected by the polarization-maintaining active fiber 4, the polarization-maintaining active fiber 4 is a double-clad fiber with an asymmetric structure, the excitation effect of the pump light on the optical fiber is improved, the quality of the first signal light and the second signal light is improved, and the operating efficiency of the seed source device A is improved.

[0073] Furthermore, the polarization-maintaining fiber coupler 3 is also connected to a grating component 5. The grating component 5 is used to manage the dispersion of the ultrashort pulse laser after the polarization-maintaining fiber coupler 3 couples the first signal light and the second signal light to obtain the ultrashort pulse laser, thereby generating laser pulses with different pulse widths and types and improving the application range of the seed source device A.

[0074] The following briefly describes the operation process of the seed source device A:

[0075] The pump source 1 transmits pump light to the polarization-maintaining fiber combiner 2. After receiving the pump light, the polarization-maintaining fiber combiner 2 couples the pump light into the first optical fiber. The pump light injects energy into the first optical fiber so that the dopant in the first optical fiber absorbs the energy and excites it, generating a first signal light and a second signal light with opposite propagation directions. Since the first signal light is transmitted in the first optical fiber, a first nonlinear phase shift can be generated, and the second signal light is transmitted in the first optical fiber and the second optical fiber, a second nonlinear phase shift can be generated. Therefore, the first nonlinear phase shift and the second nonlinear phase shift are different.

[0076] After the polarization-maintaining fiber coupler 3 receives the first signal light and the second signal light with opposite propagation directions and different nonlinear phase shifts, the first signal light and the second signal light can be coherently combined in the cone region of the polarization-maintaining fiber coupler 3 to produce a saturable absorption effect, realize NALM mode locking, and generate ultrashort pulse laser. After receiving the ultrashort pulse laser, the grating component modulates the pulse width of the ultrashort pulse laser and then outputs the processed laser so that the laser equipment can operate using the laser, thereby improving the practicality of the seed source device A.

[0077] The present application also provides a laser system (not shown), wherein the laser system includes a seed source device A and a laser device as described above, wherein the seed source device A is used to generate an ultrashort pulse laser and output it to the laser device, and the laser device uses the ultrashort pulse laser to operate, thereby improving the operating efficiency of the laser system.

[0078] The above description is only an implementation method of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A seed source device, characterized in that: It includes a pump source, a polarization-maintaining fiber combiner and a polarization-maintaining fiber coupler; The pump source is connected to the polarization-maintaining fiber combiner to generate pump light and transmit the pump light to the polarization-maintaining fiber combiner; the first output end of the polarization-maintaining fiber combiner is connected to the polarization-maintaining fiber coupler through a first optical fiber to transmit a first signal light and a second signal light to the polarization-maintaining fiber coupler, and the second output end of the polarization-maintaining fiber combiner is connected to the polarization-maintaining fiber coupler through a second optical fiber to transmit the second signal light; the polarization-maintaining fiber coupler is used to couple the first signal light and the second signal light; The nonlinear phase shift generated by the first signal light in the first optical fiber is different from the nonlinear phase shift generated by the second signal light in the first optical fiber and the second optical fiber.

2. The seed source device according to claim 1, characterized in that: The first optical fiber is a polarization-maintaining active optical fiber.

3. The seed source device according to claim 1, characterized in that: The seed source device further comprises a grating component, which is connected to the polarization-maintaining fiber coupler and is used to receive the signal light coupled by the polarization-maintaining fiber coupler and process the signal light.

4. The seed source device according to claim 3, characterized in that: The grating assembly includes a chirped fiber Bragg grating.

5. The seed source device according to claim 2, characterized in that: The polarization-maintaining active optical fiber is a double-clad optical fiber.

6. The seed source device according to claim 5, characterized in that: The double-clad optical fiber comprises a core, an inner cladding and an outer cladding, wherein the inner cladding is sleeved on the core, and the outer cladding is sleeved on the inner cladding; Wherein, the central axis of the inner cladding is staggered with the core.

7. The seed source device according to claim 5, characterized in that: The double-clad optical fiber comprises a core, an inner cladding and an outer cladding, wherein the inner cladding is sleeved on the core, and the outer cladding is sleeved on the inner cladding; Wherein, the radial cross-sectional shape of the inner cladding is one of an ellipse, a D-shape and a triangle.

8. The seed source device according to claim 2, characterized in that: A propagation direction of the first signal light is opposite to a propagation direction of the second signal light.

9. The seed source device according to claim 1, characterized in that: The pump source is a multi-mode laser.

10. A laser system, characterized in that: The invention comprises a seed source device as described in any one of claims 1 to 9, wherein the seed source device is used to generate ultrashort pulse laser.

Images