SESAM point changing device based on multi-core optical fiber fan-in and fan-out module and optical switch and laser

Abstract

The utility model discloses an SESAM switching device based on a multi-core optical fiber fan-in fan-out module and an optical switch and a laser, the SESAM switching device comprises the multi-core optical fiber fan-in fan-out module, the optical switch and a semiconductor saturable absorber mirror, and laser is excited by an external optical fiber laser system to enter the optical switch; laser selects a single-mode optical fiber from a fan-in end through the optical switch to enter the multi-core optical fiber fan-in and fan-out module, and enters a corresponding working point on the semiconductor saturable absorption mirror through a fiber core in the multi-core optical fiber at a fan-out end of the multi-core optical fiber fan-in and fan-out module. The scheme has the advantages of being easy to implement, simple to operate, simple in structure, convenient to integrate and low in dependence on the environment, the 1 * N optical switch can select a proper working point of the SESAM through computer operation, and compared with the existing technology that a single-mode fiber is connected with the SESAM, the service time of the single SESAM can be remarkably prolonged, so that the cost is reduced, and the precision is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of lasers, and in particular to a SESAM (Semiconductor Saturable Absorber Mirror) point switching device based on a multi-core optical fiber fan-in and fan-out module and an optical switch and a laser using the same, and in particular to a SESAM point switching device for a mode-locked optical fiber laser. Background Art

[0002] The statements in this section merely provide background technical information related to the present application and do not necessarily constitute prior art.

[0003] In the field of lasers, active mode locking and passive mode locking are the main means of generating pulsed lasers. Active mode locking refers to changing the loss or gain of the laser by providing a modulation signal to the laser externally, while passive mode locking uses the nonlinear absorption or phase change of the material to generate pulsed lasers. As a passive mode locking technology, SESAM mode locking technology has superior performance and high practicality, and is widely used in femtosecond and picosecond laser systems.

[0004] Since the laser pulse has high peak power and small spot, the SESAM spot position (working point) carries a high power density, so the SESAM working point is easily damaged, causing the laser system to fail. In order to avoid laser system failure, technicians need to replace the SESAM working point and recalibrate it at regular intervals. The existing method of replacing the SESAM working point generally uses precision mechanical point replacement, which has many problems. Precision machinery is easily affected by the environment and difficult to integrate, and the structure is complex and costly.

[0005] China's patent CN203288933U authorized and announced a utility model patent titled "A mode-locked laser using a SESAM point-changing device". The patent proposes a mode-locked laser using a SESAM point-changing device. The point-changing device includes an optical switch, an optical fiber, and a SESAM. The optical switch is a 1×N optical switch, where N is a natural number ≥ 2. The N output channels of the optical switch correspond to the N working points on the SESAM after passing through N optical fibers. However, this method of using optical fibers and 1×N optical switches to change points also has shortcomings. It is difficult for N optical fibers to be connected to a SESAM, and it is impossible to connect N optical fibers to the N working points of a SESAM.

[0006] In view of this, how to solve the problems of complexity and difficulty in integration of the existing method of replacing the SESAM working point using precision mechanical point replacement and difficulty in implementation of the method of using optical fiber and 1×N optical switch point replacement has become the subject to be studied and solved by the utility model. Utility Model Content

[0007] The utility model aims to provide a SESAM point switching device and a laser based on a multi-core optical fiber fan-in fan-out module and an optical switch.

[0008] To achieve the above-mentioned purpose, the first aspect of the utility model proposes a SESAM point switching device based on a multi-core fiber fan-in fan-out module and an optical switch, which is used for switching the SESAM working point of a fiber laser system. The innovation thereof is:

[0009] The SESAM switching device comprises a multi-core optical fiber fan-in and fan-out module, an optical switch, and a semiconductor saturable absorption mirror.

[0010] The multi-core fiber fan-in and fan-out module is a device for coupling each core in a multi-core fiber with multiple single-mode fibers. The fan-in end of the multi-core fiber fan-in and fan-out module has N single-mode fibers, and the fan-out end of the multi-core fiber fan-in and fan-out module has a multi-core fiber. The multi-core fiber has N cores, and the N single-mode fibers correspond one-to-one to the N cores in the multi-core fiber.

[0011] The optical switch is a 1×N optical switch, and the optical switch is arranged between the optical path of the external optical fiber laser system and N single-mode optical fibers through an optical path.

[0012] The semiconductor saturable absorber mirror is connected to the multi-core optical fiber at the fan-out end of the multi-core optical fiber fan-in and fan-out module. The semiconductor saturable absorber mirror has N working points, and the N cores on the multi-core optical fiber correspond one-to-one to the N working points on the SESAM.

[0013] The SESAM switching device is configured as follows: an external fiber laser system excites laser light to enter the optical switch, the laser selects a single-mode optical fiber from the fan-in end through the optical switch to enter the multi-core optical fiber fan-in and fan-out module, and one of the cores of the multi-core optical fiber at the fan-out end of the multi-core optical fiber fan-in and fan-out module enters the corresponding working point on the semiconductor saturable absorber mirror.

[0014] To achieve the above-mentioned purpose, the second aspect of the present invention proposes a linear cavity SESAM mode-locked fiber laser using a SESAM point-changing device, the innovation of which lies in that the linear cavity SESAM mode-locked fiber laser comprises the SESAM point-changing device as described in the first aspect of the present invention, as well as a semiconductor laser, a wavelength division multiplexer, a gain fiber, and a fiber grating.

[0015] To achieve the above-mentioned purpose, the third aspect of the utility model proposes a ring-cavity SESAM mode-locked fiber laser using a SESAM point-changing device, the innovation of which lies in that the ring-cavity SESAM mode-locked fiber laser comprises the SESAM point-changing device as described in the first aspect of the utility model, as well as a semiconductor laser, a wavelength division multiplexer, a gain fiber, a circulator, and a fiber coupler.

[0016] To achieve the above-mentioned purpose, the fourth aspect of the utility model proposes a linear cavity SESAM mode-locked fiber laser using a SESAM point-changing device, the innovation of which lies in that the linear cavity SESAM mode-locked fiber laser comprises the SESAM point-changing device as described in the first aspect of the utility model, as well as a semiconductor laser, a wavelength division multiplexer, a fiber grating, a gain fiber, and a fiber isolator.

[0017] The relevant contents of this utility model are explained as follows:

[0018] 1. In the above technical scheme of the utility model, in view of the problems that the existing method of replacing the SESAM working point by using precision mechanical point-changing is complicated and difficult to integrate, and the method of using optical fiber and 1×N optical switch to change the point is difficult to implement, a point-changing device that is easy to implement, simple in structure and simple in operation is designed and developed, which is a SESAM point-changing device and a laser based on a multi-core optical fiber fan-in fan-out module and an optical switch. The SESAM point-changing device includes a multi-core optical fiber fan-in fan-out module, an optical switch, and a semiconductor saturable absorber mirror (SESAM). The multi-core optical fiber fan-in fan-out module is a device for coupling each fiber core in a multi-core optical fiber with multiple single-mode optical fibers. The optical switch is a 1×N optical switch. The semiconductor saturable absorber mirror (SESAM) There are N working points on the receiving mirror, and the N cores on the multi-core optical fiber correspond to the N working points on the SESAM one by one. The laser is excited by the external optical fiber laser system to enter the optical switch, and the laser selects a single-mode optical fiber from the fan-in end through the optical switch to enter the multi-core optical fiber fan-in fan-out module, and one core of the multi-core optical fiber at the fan-out end of the multi-core optical fiber fan-in fan-out module enters the corresponding working point on the semiconductor saturable absorber mirror; the 1×N optical switch can be controlled by a computer to select a single-mode optical fiber. When the working point is close to the damage threshold, the 1×N optical switch can select other channels to allow the laser to enter other working points of the SESAM. Repeat the above steps to complete the SESAM point change. The utility model realizes SESAM point change based on the multi-core optical fiber fan-in fan-out module and the optical switch, and has the advantages of easy implementation, simple operation, simple structure, convenient integration, and low dependence on the environment. The 1×N optical switch can select a suitable working point of the SESAM through computer operation. Compared with the current technology of connecting single-mode optical fiber to SESAM, the use time of a single SESAM can be significantly increased.

[0019] 2. In the technical solution of the first aspect above, the multi-core optical fiber includes a cladding and N fiber cores arranged inside the cladding, where N is greater than or equal to 7.

[0020] 3. In the technical solution of the first aspect above, the semiconductor saturable absorber mirror is fixed on the multi-core optical fiber by gel.

[0021] 4. In the technical solution of the second aspect above, the semiconductor laser is optically connected to the first port of the wavelength division multiplexer, the second port of the wavelength division multiplexer, the gain fiber, the optical switch, the single-mode fiber, the multi-core fiber fan-in and fan-out module, the multi-core fiber, and the semiconductor saturable absorber mirror in sequence, and the third port of the wavelength division multiplexer is optically connected to the fiber Bragg grating; the linear cavity SESAM mode-locked fiber laser is configured so that the laser generated by the semiconductor laser passes through the semiconductor saturable absorber mirror in sequence, and then returns to the wavelength division multiplexer through reflection of the semiconductor saturable absorber mirror along the original path, and the laser passing through the wavelength division multiplexer enters the fiber Bragg grating from the third port and is output.

[0022] 5. In the technical solution of the third aspect above, the semiconductor laser is optically connected to the first port of the wavelength division multiplexer, the second port of the wavelength division multiplexer, the gain fiber, and the first port of the circulator in sequence, and then one of the paths is optically connected to the optical switch, the single-mode optical fiber, the multi-core optical fiber fan-in and fan-out module, the multi-core optical fiber, and the semiconductor saturable absorber mirror in sequence through the second port of the circulator, and the other path is optically connected to the fiber coupler through the third port of the circulator, the third port of the fiber coupler is connected to the third port of the wavelength division multiplexer, and the second port of the fiber coupler serves as the output port.

[0023] 6. In the technical solution of the fourth aspect above, the semiconductor laser is optically connected to the first port of the wavelength division multiplexer, the second port of the wavelength division multiplexer, the fiber Bragg grating, the gain fiber, the optical switch, the single-mode fiber, the multi-core fiber fan-in and fan-out module, the multi-core fiber, and the semiconductor saturable absorber mirror in sequence, and the third port of the wavelength division multiplexer is optically connected to the fiber isolator; the linear cavity SESAM mode-locked fiber laser is configured so that the laser generated by the semiconductor laser passes through the semiconductor saturable absorber mirror in sequence, and then reflects back to the fiber Bragg grating, the wavelength division multiplexer, and the fiber isolator through the semiconductor saturable absorber mirror, and then outputs the laser through the fiber isolator.

[0024] 7. In this utility model, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0025] 8. In the present utility model, the terms "center", "upper", "lower", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional assembly relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application; if the manual pressure relief valve is turned upside down or placed horizontally, the corresponding orientation should also be adjusted accordingly.

[0026] 9. In the present invention, the terms "first", "second", etc. are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0027] 10. In addition, the term "and / or" in this application means three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or a solution in which both A and B are satisfied.

[0028] Due to the application of the above scheme, the utility model has the following advantages and effects compared with the prior art:

[0029] The above-mentioned scheme of the utility model realizes SESAM point switching based on a multi-core optical fiber fan-in and fan-out module and an optical switch, and has the advantages of easy implementation, simple operation, simple structure, convenient integration, and low dependence on the environment. The 1×N optical switch can select a suitable working point of the SESAM through computer operation. Compared with the current technology of connecting single-mode optical fiber to SESAM, it can significantly increase the use time of a single SESAM, thereby reducing costs and improving accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the structure of a SESAM switching device based on a multi-core optical fiber fan-in and fan-out module and an optical switch in Embodiment 1 of the present utility model;

[0031] Figure 2 This is a schematic diagram of the structure of a multi-core optical fiber in an embodiment of the utility model;

[0032] Figure 3 This is a schematic diagram of the structure of a linear cavity SESAM mode-locked fiber laser using a SESAM point-changing device in Example 2 of the utility model;

[0033] Figure 4 This is a schematic diagram of the structure of a ring cavity SESAM mode-locked fiber laser using a SESAM point-changing device in Embodiment 3 of the present utility model;

[0034] Figure 5 This is a schematic structural diagram of a linear cavity SESAM mode-locked fiber laser using a SESAM point-changing device according to a fourth embodiment of the utility model.

[0035] The various parts of the above drawings are shown as follows:

[0036] 1 Multi-fiber fan-in and fan-out modules

[0037] 2 Optical switch

[0038] 3 Semiconductor Saturable Absorber Mirror

[0039] 4 Single-mode fiber

[0040] 5 Multi-core optical fiber

[0041] 51 Cladding

[0042] 52 core

[0043] 6 Semiconductor Laser

[0044] 7 Wavelength Division Multiplexer

[0045] 8 Gain Fiber

[0046] 9 Fiber Bragg Grating

[0047] 10 Circulator

[0048] 11 Fiber Optic Coupler

[0049] 12 Fiber optic isolator.

[0050] In the drawings of the specification, the first port of each device is represented by I, the second port is represented by II, the third port is represented by III, and the arrow indicates the laser output direction. DETAILED DESCRIPTION

[0051] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0052] The utility model aims to solve the problems of the existing SESAM working point replacement method using precision mechanical point replacement, which is complicated and difficult to integrate, and the point replacement method using optical fiber and 1×N optical switch 2, which is difficult to implement, so as to provide the following point replacement solution device and laser which is easy to implement, simple in structure and simple in operation:

[0053] 1. A SESAM switching device based on a multi-core optical fiber fan-in fan-out module and an optical switch, the SESAM switching device comprising a multi-core optical fiber fan-in fan-out module 1, an optical switch 2, and a semiconductor saturable absorber mirror 3.

[0054] 2. A linear cavity SESAM mode-locked fiber laser using a SESAM switching device, comprising a SESAM switching device, a semiconductor laser 6, a wavelength division multiplexer 7, a gain fiber 8, and a fiber grating 9.

[0055] 3. A ring cavity SESAM mode-locked fiber laser using a SESAM switching device, comprising a SESAM switching device, a semiconductor laser 6, a wavelength division multiplexer 7, a gain fiber 8, a circulator 10, and a fiber coupler 11.

[0056] 4. A linear cavity SESAM mode-locked fiber laser using a SESAM switching device, comprising a SESAM switching device, a semiconductor laser 6, a wavelength division multiplexer 7, a fiber grating 9, a gain fiber 8, and a fiber isolator 12.

[0057] Embodiment 1, as Figure 1 and Figure 2 As shown, Embodiment 1 of the utility model discloses a SESAM point switching device based on a multi-core fiber fan-in fan-out module and an optical switch, which is used for switching the SESAM working point of a fiber laser system. The SESAM point switching device includes a multi-core fiber fan-in fan-out module 1, an optical switch 2, and a semiconductor saturable absorber mirror 3.

[0058] The multi-core fiber fan-in and fan-out module 1 is a device for coupling each fiber core 52 in a multi-core fiber 5 with multiple single-mode fibers 4. The fan-in end of the multi-core fiber fan-in and fan-out module 1 has N single-mode fibers 4, and the fan-out end of the multi-core fiber fan-in and fan-out module 1 has a multi-core fiber 5. The multi-core fiber 5 has N fiber cores 52, and the N single-mode fibers 4 correspond one-to-one to the N fiber cores 52 in the multi-core fiber 5.

[0059] The optical switch 2 is a 1×N optical switch 2 , and the optical switch 2 is arranged between the optical path of the external fiber laser system and N single-mode optical fibers 4 through an optical path.

[0060] The semiconductor saturable absorber mirror 3 is connected to the multi-core optical fiber 5 at the fan-out end of the multi-core optical fiber fan-in and fan-out module 1. The semiconductor saturable absorber mirror 3 has N working points, and the N fiber cores 52 on the multi-core optical fiber 5 correspond one-to-one to the N working points on the SESAM.

[0061] The SESAM switching device is configured as follows: the laser is excited by an external fiber laser system to enter the optical switch 2, the laser selects a single-mode optical fiber 4 from the fan-in end through the optical switch 2 to enter the multi-core optical fiber fan-in and fan-out module 1, and enters the corresponding working point on the semiconductor saturable absorber mirror 3 from a core 52 in the multi-core optical fiber 5 at the fan-out end of the multi-core optical fiber fan-in and fan-out module 1.

[0062] Through the implementation of the first embodiment of the utility model, the SESAM switching device includes a multi-core fiber fan-in fan-out module 1, an optical switch 2, and a semiconductor saturable absorber mirror 3 (SESAM). The multi-core fiber fan-in fan-out module 1 is a device for coupling each core 52 in the multi-core optical fiber 5 with multiple single-mode optical fibers 4. The optical switch 2 is a 1×N optical switch 2. The semiconductor saturable absorber mirror 3 has N working points. The N cores 52 on the multi-core optical fiber 5 correspond to the N working points on the SESAM one by one. The laser is excited by an external fiber laser system to enter the optical switch. 2. The laser selects a single-mode optical fiber 4 from the fan-in end through the optical switch 2 to enter the multi-core optical fiber fan-in and fan-out module 1, and enters the corresponding working point on the semiconductor saturable absorber mirror 3 through a core 52 of the multi-core optical fiber 5 at the fan-out end of the multi-core optical fiber fan-in and fan-out module 1; the 1×N optical switch 2 can be controlled by a computer to select the single-mode optical fiber 4. When the working point is close to the damage threshold, the 1×N optical switch 2 can select other channels to allow the laser to enter other working points of the SESAM. Repeat the above steps to complete the SESAM point change. The utility model realizes the SESAM point change based on the multi-core optical fiber fan-in and fan-out module 1 and the optical switch 2, and has the advantages of easy implementation, simple operation, simple structure, convenient integration, and low dependence on the environment. The 1×N optical switch 2 can select the appropriate working point of the SESAM through computer operation. Compared with the current technology of connecting the single-mode optical fiber 4 with the SESAM, the use time of a single SESAM can be significantly increased.

[0063] In the first embodiment of the present invention, Figure 2 As shown, the multi-core optical fiber 5 includes a cladding 51 and N fiber cores 52 arranged inside the cladding 51, wherein N is greater than or equal to 7, but the utility model is not limited to this. The figure shows the cladding 51 of the multi-core optical fiber 5, and the small circles in the middle of the cladding 51 and around it are the 7 fiber cores 52 of the multi-core optical fiber 5, and the number of fiber cores 52 can continue to increase.

[0064] In the first embodiment of the present invention, the semiconductor saturable absorber mirror 3 is fixed on the multi-core optical fiber 5 by gel. Using gel to fix SESAM can ensure its stability and reliability on the optical fiber, while reducing the impact of the external environment on the performance of SESAM. In addition, the gel can also provide a certain buffering and shock-absorbing effect to protect SESAM from mechanical shock and vibration.

[0065] The usage process of the first embodiment of the present invention can be referred to as follows:

[0066] Step 1: The laser system emits laser light which enters the 1×N optical switch 2.

[0067] Step 2: The laser selects a channel through the optical switch 2 to enter the multi-core optical fiber fan-in and fan-out module 1 and enter the multi-core optical fiber 5.

[0068] Step 3: The laser enters a working point of the SESAM through a core 52 of the multi-core optical fiber 5.

[0069] After the SESAM works at this working point for a period of time, it returns to step 1 and uses the 1×N optical switch 2 to switch to other channels, thereby entering other working points of the SESAM.

[0070] Embodiment 2, as Figure 3 As shown, the second embodiment of the present invention proposes a linear cavity SESAM mode-locked fiber laser using a SESAM point-changing device, and its innovation lies in: the linear cavity SESAM mode-locked fiber laser includes the SESAM point-changing device as described in the first aspect of the present invention, as well as a semiconductor laser 6, a wavelength division multiplexer 7, a gain fiber 8, and a fiber grating 9.

[0071] In the second embodiment of the present utility model, the semiconductor laser 6 is optically connected to the first port of the wavelength division multiplexer 7, the second port of the wavelength division multiplexer 7, the gain fiber 8, the optical switch 2, the single-mode fiber 4, the multi-core fiber fan-in and fan-out module 1, the multi-core fiber 5, and the semiconductor saturable absorber mirror 3 in sequence, and the third port of the wavelength division multiplexer 7 is optically connected to the fiber grating 9; the linear cavity SESAM mode-locked fiber laser is configured so that the laser generated by the semiconductor laser 6 passes through the semiconductor saturable absorber mirror 3 in sequence, and then returns to the wavelength division multiplexer 7 through the semiconductor saturable absorber mirror 3 to reflect the original path, and the laser passing through the wavelength division multiplexer 7 enters the fiber grating 9 from the third port and is output.

[0072] refer to Figure 3 , the specific implementation of the second embodiment of the utility model is as follows: the laser generated by the semiconductor laser 6 (LD) passes through the first port of the wavelength division multiplexer 7 (WDM), the second port of the wavelength division multiplexer 7 (WDM), and the gain fiber 8 in sequence, and then the laser passes through the single-mode fiber 4, the optical switch 2, the multi-core fiber fan-in and fan-out module 1, and the SESAM, and is reflected by the SESAM and returns to the wavelength division multiplexer 7 (WDM) along the original path. Most of the laser light passing through the wavelength division multiplexer 7 (WDM) is output from the third port of the wavelength division multiplexer 7 (WDM), passes through the Bragg fiber grating 9FBG, and a part of it returns to the laser cavity to continue oscillating, and a part of it outputs laser light.

[0073] Embodiment three, as Figure 4 As shown, the third embodiment of the utility model proposes a ring cavity SESAM mode-locked fiber laser using a SESAM switching device, including a SESAM switching device, a semiconductor laser 6, a wavelength division multiplexer 7, a gain fiber 8, a circulator 10, and a fiber coupler 11.

[0074] In the third embodiment of the present invention, the semiconductor laser 6 is optically connected to the first port of the wavelength division multiplexer 7, the second port of the wavelength division multiplexer 7, the gain fiber 8, and the first port of the circulator 10 in sequence, and then one of the paths is optically connected to the optical switch 2, the single-mode optical fiber 4, the multi-core optical fiber fan-in and fan-out module 1, the multi-core optical fiber 5, and the semiconductor saturable absorber 3 in sequence through the second port of the circulator 10, and the other path is optically connected to the fiber coupler 11 through the third port of the circulator 10, and the third port of the fiber coupler 11 is connected to the third port of the wavelength division multiplexer 7, and the second port of the fiber coupler 11 is used as the output port.

[0075] refer to Figure 4 The structure diagram of the utility model, the specific implementation of the third embodiment of the present invention is: the laser generated by the semiconductor laser 6 (LD) passes through the first port of the wavelength division multiplexer 7 (WDM), the second port of the wavelength division multiplexer 7 (WDM), and the gain fiber 8 in sequence, and then the laser passes through the first port of the circulator 10, and the second port of the circulator 10 is connected to the 1×N optical switch 2. The laser passes through the 1×N optical switch 2, the multi-core fiber fan-in and fan-out module 1, and the SESAM in sequence, and is reflected by the SESAM and returns to the second port of the circulator 10. The laser enters the first port of the optical fiber coupler 11 through the third port of the circulator 10, a part of which is output from the second port of the optical fiber coupler 11, and the other part enters the ring cavity through the third port of the optical fiber coupler 11 to continue oscillating.

[0076] Embodiment 4, as Figure 5 As shown, the fourth embodiment of the utility model proposes a linear cavity SESAM mode-locked fiber laser using a SESAM switching device, including a SESAM switching device, a semiconductor laser 6, a wavelength division multiplexer 7, a fiber grating 9, a gain fiber 8, and a fiber isolator 12.

[0077] In the fourth embodiment of the present utility model, the semiconductor laser 6 is optically connected to the first port of the wavelength division multiplexer 7, the second port of the wavelength division multiplexer 7, the fiber grating 9, the gain fiber 8, the optical switch 2, the single-mode fiber 4, the multi-core fiber fan-in and fan-out module 1, the multi-core fiber 5, and the semiconductor saturable absorber mirror 3 in sequence, and the third port of the wavelength division multiplexer 7 is optically connected to the optical fiber isolator 12; the linear cavity SESAM mode-locked fiber laser is configured so that the laser generated by the semiconductor laser 6 passes through the semiconductor saturable absorber mirror 3 in sequence, and then reflects the semiconductor saturable absorber mirror 3 back to the fiber grating 9, the wavelength division multiplexer 7, and the optical fiber isolator 12 along the original path, and then outputs the laser through the optical fiber isolator 12.

[0078] refer to Figure 5 The structure diagram of the utility model, the specific implementation method of the fourth embodiment of the utility model is: the laser generated by the semiconductor laser 6 (LD) passes through the first port of the wavelength division multiplexer 7 (WDM), the second port of the wavelength division multiplexer 7 (WDM), the fiber grating 9, and the gain fiber 8 in sequence, and then the laser passes through the single-mode fiber 4, the optical switch 2, the multi-core fiber fan-in and fan-out module 1, and the SESAM, and is reflected by the SESAM and returns to the fiber grating 9 along the original path. A part of the laser is reflected back to the resonant cavity through the fiber grating 9 to continue oscillating, and a part of the laser is transmitted to the second port of the wavelength division multiplexer 7 (WDM). Most of the laser passing through the wavelength division multiplexer 7 (WDM) will be output from the third port of the wavelength division multiplexer 7 (WDM), and the laser is output through the optical fiber isolator 12 (ISO).

[0079] The above embodiments are only for illustrating the technical concept and features of the utility model, and their purpose is to enable people familiar with the technology to understand the content of the utility model and implement it accordingly, and they cannot be used to limit the protection scope of the utility model. Any equivalent changes or modifications made according to the spirit of the utility model should be included in the protection scope of the utility model.

Claims

1. A SESAM point switching device based on a multi-core fiber fan-in fan-out module and an optical switch, used for switching the SESAM working point of a fiber laser system, characterized by: The SESAM switching device comprises a multi-core optical fiber fan-in and fan-out module (1), an optical switch (2), and a semiconductor saturable absorber mirror (3); The multi-core optical fiber fan-in and fan-out module (1) is a device for realizing coupling between each fiber core (52) in a multi-core optical fiber (5) and a plurality of single-mode optical fibers (4); the fan-in end of the multi-core optical fiber fan-in and fan-out module (1) has N single-mode optical fibers (4); the fan-out end of the multi-core optical fiber fan-in and fan-out module (1) has a multi-core optical fiber (5); the multi-core optical fiber (5) has N fiber cores (52); the N single-mode optical fibers (4) correspond one to one with the N fiber cores (52) in the multi-core optical fiber (5); The optical switch (2) is a 1×N optical switch (2), and the optical switch (2) is arranged between an optical path of an external optical fiber laser system and N single-mode optical fibers (4) through an optical path; The semiconductor saturable absorber mirror (3) is connected to the multi-core optical fiber (5) at the fan-out end of the multi-core optical fiber fan-in and fan-out module (1), the semiconductor saturable absorber mirror (3) has N working points, and the N fiber cores (52) on the multi-core optical fiber (5) correspond one-to-one to the N working points on the SESAM; The SESAM switching device is configured such that: an external fiber laser system excites laser light to enter the optical switch (2); the laser light selects a single-mode optical fiber (4) from a fan-in end through the optical switch (2) to enter the multi-core optical fiber fan-in and fan-out module (1); and a core (52) in the multi-core optical fiber (5) at the fan-out end of the multi-core optical fiber fan-in and fan-out module (1) enters a corresponding working point on the semiconductor saturable absorber mirror (3).

2. The SESAM switching device based on a multi-core optical fiber fan-in and fan-out module and an optical switch according to claim 1, characterized in that: The multi-core optical fiber (5) comprises a cladding (51) and N fiber cores (52) arranged inside the cladding (51), wherein N is greater than or equal to 7.

3. The SESAM switching device based on a multi-core optical fiber fan-in and fan-out module and an optical switch according to claim 2, characterized in that: The semiconductor saturable absorber mirror (3) is fixed on the multi-core optical fiber (5) via gel.

4. A linear cavity SESAM mode-locked fiber laser using a SESAM point-changing device, characterized in that: The linear cavity SESAM mode-locked fiber laser comprises the SESAM switching device as claimed in any one of claims 1 to 3, as well as a semiconductor laser (6), a wavelength division multiplexer (7), a gain fiber (8), and a fiber grating (9).

5. The linear cavity SESAM mode-locked fiber laser using the SESAM point changing device according to claim 4, characterized in that: The semiconductor laser (6) is optically connected in sequence to the first port of the wavelength division multiplexer (7), the second port of the wavelength division multiplexer (7), the gain fiber (8), the optical switch (2), the single-mode fiber (4), the multi-core fiber fan-in and fan-out module (1), the multi-core fiber (5), and the semiconductor saturable absorber mirror (3); the third port of the wavelength division multiplexer (7) is optically connected to the fiber grating (9); the linear cavity SESAM mode-locked fiber laser is configured such that the laser light generated by the semiconductor laser (6) passes through the semiconductor saturable absorber mirror (3) in sequence, and then returns to the wavelength division multiplexer (7) through reflection of the semiconductor saturable absorber mirror (3); the laser light passing through the wavelength division multiplexer (7) enters the fiber grating (9) from the third port and is then output.

6. A ring cavity SESAM mode-locked fiber laser using a SESAM point changing device, characterized in that: The ring cavity SESAM mode-locked fiber laser comprises the SESAM switching device as claimed in any one of claims 1 to 3, as well as a semiconductor laser (6), a wavelength division multiplexer (7), a gain fiber (8), a circulator (10), and a fiber coupler (11).

7. The ring cavity SESAM mode-locked fiber laser using the SESAM point changing device according to claim 6, characterized in that: The semiconductor laser (6) is optically connected to the first port of the wavelength division multiplexer (7), the second port of the wavelength division multiplexer (7), the gain fiber (8), and the first port of the circulator (10) in sequence, and then one of the paths is optically connected to the optical switch (2), the single-mode optical fiber (4), the multi-core optical fiber fan-in and fan-out module (1), the multi-core optical fiber (5), and the semiconductor saturable absorber (3) in sequence through the second port of the circulator (10), and the other path is optically connected to the optical fiber coupler (11) through the third port of the circulator (10), the third port of the optical fiber coupler (11) is connected to the third port of the wavelength division multiplexer (7), and the second port of the optical fiber coupler (11) serves as an output port.

8. A linear cavity SESAM mode-locked fiber laser using a SESAM point-changing device, characterized in that: The linear cavity SESAM mode-locked fiber laser comprises the SESAM switching device as claimed in any one of claims 1 to 3, as well as a semiconductor laser (6), a wavelength division multiplexer (7), a fiber grating (9), a gain fiber (8), and a fiber isolator (12).

9. The linear cavity SESAM mode-locked fiber laser using the SESAM point changing device according to claim 8, characterized in that: The semiconductor laser (6) is optically connected to the first port of the wavelength division multiplexer (7), the second port of the wavelength division multiplexer (7), the fiber grating (9), the gain fiber (8), the optical switch (2), the single-mode fiber (4), the multi-core fiber fan-in and fan-out module (1), the multi-core fiber (5), and the semiconductor saturable absorber mirror (3) in sequence, and the third port of the wavelength division multiplexer (7) is optically connected to the optical fiber isolator (12); the linear cavity SESAM mode-locked fiber laser is configured such that the laser light generated by the semiconductor laser (6) passes through the semiconductor saturable absorber mirror (3) in sequence, and then returns to the fiber grating (9), the wavelength division multiplexer (7), and the optical fiber isolator (12) through reflection of the semiconductor saturable absorber mirror (3), and then outputs the laser light through the optical fiber isolator (12).

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