Compact mode-locked fiber laser

Abstract

The invention discloses a compact mode-locked fiber laser, which belongs to the technical field of time frequency and comprises a shell, an optical device and an electrical device, the interior of the shell is divided into a space A and a space B; the electrical device comprises a laser adapter plate, a circuit control board and a semiconductor laser driving board; the laser adapter plate and the circuit control board are located in the space A, and the semiconductor laser driving board is located in the space B; the optical device is located in the space A; the optical device comprises a collimator, a half-wave plate, a polarization beam splitter, an optical isolator, a PZT, a semiconductor laser, a wavelength division multiplexer and two 1 / 4 wave plates. The semiconductor laser is mounted on the laser adapter plate; the wavelength division multiplexer is connected with the semiconductor laser, the collimator and the PZT through optical fibers. According to the invention, layout optimization of internal devices of the mode-locked fiber laser is realized, and the influence of temperature during integrated arrangement is solved on the basis of realizing miniaturization, so that the mode-locked stability is ensured.

Description

Technical Field

[0001] The invention belongs to the field of time-frequency technology, and in particular relates to a compact mode-locked fiber laser. Background Art

[0002] Fiber lasers have attracted great attention for their advantages such as good beam quality, high efficiency, easy integration, good heat dissipation, and flexible structure. They have been successfully applied in the fields of fiber-optic communications, fiber-optic sensing, and ultrafast optics. Mode-locked fiber lasers are based on fiber lasers and use the method of mode locking to make the fiber laser output a series of ultrashort pulses. This type of laser is called a mode-locked fiber laser. Nonlinear polarization rotation mode locking technology is one of the most commonly used mode locking technologies, and it is also one of the main means to achieve all-fiber mode locking in fiber mode-locked fiber lasers.

[0003] At present, many oscillators, the core components of mode-locked fiber lasers, have been miniaturized. However, mode-locked fiber lasers are mainly built on optical platforms. Optical applications also involve a variety of circuits, and the components are scattered and difficult to transport. It is difficult to truly achieve miniaturized applications, and the stability of on-site construction cannot be guaranteed. The reasons are:

[0004] Fiber lasers include semiconductor laser driver boards. Since semiconductor laser driver boards contain power devices such as MOS tubes, TEC temperature controllers, and power inductors, they will generate a lot of heat when the semiconductor laser driver board is working normally, causing the heat in the cavity to increase, which will cause a significant drift in the cavity temperature, and then cause the repetition frequency of the optical frequency comb of the semiconductor laser to have a large frequency jitter. On the one hand, it will reduce the stability of the entire mode-locked laser, and on the other hand, it will lead to a decrease in accuracy after repetition frequency locking and a shortened locking time, which will have an adverse effect on both the short-term and long-term stability of the mode-locked laser.

[0005] Therefore, it is necessary to optimize the layout of optical and electrical devices in the mode-locked fiber laser so that the mode-locked fiber laser can meet the commercial requirements of miniaturization and high efficiency. Summary of the invention

[0006] In view of this, the present invention provides a compact mode-locked fiber laser, which realizes the layout optimization of the internal devices of the mode-locked fiber laser, compactly integrates the optical devices and the electrical devices, solves the influence of temperature in the integrated layout on the basis of miniaturization, thereby ensuring the mode-locking stability of the mode-locked fiber laser.

[0007] The present invention is achieved through the following technical solutions:

[0008] A compact mode-locked fiber laser comprises: a housing and optical and electrical components arranged inside the housing;

[0009] The interior of the shell is divided into two spaces, space A and space B.

[0010] The electrical components include: a laser adapter board, a circuit control board and a semiconductor laser driver board;

[0011] The laser adapter board and the circuit control board are located in space A, and the semiconductor laser driver board is located in space B;

[0012] The semiconductor laser driving board is electrically connected to the circuit control board;

[0013] The laser adapter board is electrically connected to the semiconductor laser driver board;

[0014] The optical devices are located in space A; the optical devices include: a collimator, a half-wave plate, a polarization beam splitter, an optical isolator, a PZT, a semiconductor laser, a wavelength division multiplexer and two quarter-wave plates;

[0015] A collimator, a quarter wave plate, a half wave plate, a polarization beam splitter, an optical isolator, another quarter wave plate and a PZT are coaxially arranged in sequence inside the housing;

[0016] The light exit hole of the polarization beam splitter is opposite to the light exit hole on the housing;

[0017] The semiconductor laser is mounted on the laser adapter board, and the two are electrically connected;

[0018] The wavelength division multiplexer is connected to the semiconductor laser, the collimator and the PZT through optical fibers respectively.

[0019] Furthermore, a partition is provided inside the shell;

[0020] The internal space of the shell is divided into space A and space B by a partition;

[0021] The semiconductor laser driving board is mounted on the partition or the side wall of the housing;

[0022] The laser adapter board, circuit control board, collimator, half-wave plate, polarization beam splitter, optical isolator, PZT, wavelength division multiplexer and two 1 / 4 wave plates are installed on the upper end surface of the partition.

[0023] Furthermore, the upper end surface of the partition is divided into area A and area B;

[0024] The semiconductor laser and the wavelength division multiplexer are located in area A of the partition;

[0025] The collimator, two quarter wave plates, a half wave plate, a polarization beam splitter, an optical isolator and a PZT are located in region B of the partition.

[0026] Furthermore, the circuit control board is located in the space A and is installed on the inner wall of the shell.

[0027] Furthermore, the mode-locked fiber laser further comprises: an indicator light and a switch;

[0028] The indicator light and the switch are respectively mounted on the circuit control board, and the indicator light and the switch are respectively electrically connected to the circuit control board;

[0029] The side wall surface of the housing on which the circuit control board is mounted is processed with an indicator light hole and a switch hole;

[0030] The indicator light is opposite to the indicator light hole, and the indicator light extends out of the housing through the indicator light hole;

[0031] The switch is opposite to the switch hole, and the switch extends out of the shell through the switch hole.

[0032] Furthermore, the semiconductor laser is fastened and mounted on the laser adapter plate by fasteners.

[0033] Furthermore, the housing comprises: an outer shell, an upper cover plate and a lower cover plate;

[0034] The shell is open at both ends; the partition is arranged on the inner wall surface of the shell; the partition is parallel to the two open end surfaces of the shell;

[0035] The upper cover plate and the lower cover plate are respectively mounted on the two opening ends of the shell.

[0036] Beneficial effects:

[0037] (1) A compact mode-locked fiber laser in the present invention, wherein electrical and optical devices are installed inside a housing; the housing is conducive to maintaining the stability of the internal environment of the mode-locked fiber laser, and can protect the control circuit board, and prevent the control circuit board from being short-circuited due to accidental touch, thereby ensuring the long-term stable operation of the mode-locked fiber laser; the mode-locked fiber laser optimizes the layout of the internal electrical and optical devices, and realizes an optoelectronic integrated design; the interior of the housing is divided into space A and space B, and a laser adapter board, a circuit control board, a collimator, a half-wave plate, a semiconductor laser, and a polarization beam splitter are installed inside the housing. The optical isolator, PZT, wavelength division multiplexer and two 1 / 4 wave plates are located in space A, and the semiconductor laser driving board is located in space B; the mode-locked fiber laser isolates the semiconductor laser driving board from the optical device, thereby preventing the heat generated by the semiconductor laser driving board during operation from affecting the mode-locking stability, thereby improving the mode-locking effect; the optical device forms a ring cavity structure in the mode-locked fiber laser, which can generate and output stable mode-locked femtosecond pulses and realize self-starting mode locking; therefore, the mode-locked fiber laser reduces the structure occupied space of the mode-locked fiber laser while ensuring the mode-locking effect.

[0038] (2) In a compact mode-locked fiber laser of the present invention, the plate surface of the partition is divided into area A and area B, the semiconductor laser and the wavelength division multiplexer are located in area A of the partition, and the collimator, two 1 / 4 wave plates, a half-wave plate, a polarization beam splitter, an optical isolator and a PZT are located in area B of the partition. The above division method can reduce the interference of the heat generated by the semiconductor laser and the wavelength division multiplexer during operation on other optical devices, and can further ensure the stability and reliability of the mode-locked fiber laser.

[0039] (3) A compact mode-locked fiber laser in the present invention further includes an indicator light and a switch, and the operating status of the mode-locked fiber laser can be monitored by the indicator light.

[0040] (4) In a compact mode-locked fiber laser of the present invention, the semiconductor laser is fastened to the laser adapter plate by fasteners, so that the semiconductor laser and the laser adapter plate can fit tightly together to ensure sufficient contact area. The heat of the semiconductor laser is transferred to the laser adapter plate, and then transferred to the partition through the laser adapter plate, and then transferred to the housing, thereby improving the heat dissipation effect and avoiding the influence of temperature on the stability of mode locking. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a three-dimensional diagram of the overall appearance of the present invention;

[0042] Figure 2 It is a bottom view of the present invention (without the lower cover plate);

[0043] Figure 3 It is a top view of the present invention (without the upper cover plate);

[0044] Figure 4 It is a side view of the present invention (without the upper cover plate);

[0045] Figure 5 It is a cross-sectional view of the right side of the present invention at AA;

[0046] Figure 6 It is a cross-sectional view of the front side BB of the present invention;

[0047] Among them, 1-housing, 101-partition, 102-indicator hole, 103-switch hole, 104-electric plug hole, 105-light output hole, 2-upper cover, 3-lower cover, 4-circuit control board, 5-semiconductor laser driving board, 6-laser adapter board, 7-semiconductor laser, 8-wavelength division multiplexer, 9-collimator, 10-1 / 4 wave plate, 11-half wave plate, 12-polarization beam splitter, 13-optical isolator, 14-PZT. DETAILED DESCRIPTION

[0048] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0049] This embodiment provides a compact mode-locked fiber laser, such as Figures 1 to 3 As shown, it includes: a shell, optical devices and electrical devices.

[0050] like Figure 1 As shown, the shell is a rectangular parallelepiped structure, including: an outer shell 1, an upper cover plate 2 and a lower cover plate 3.

[0051] The housing 1 is open at both ends. A partition 101 is provided on the inner wall of the housing 1. The partition 101 is parallel to the two open end surfaces of the housing 1, and the partition 101 divides the internal space of the housing 1 into two parts, upper and lower. The two spaces are space A and space B respectively. At the same time, the upper end surface of the partition 101 is divided into area A and area B. A light outlet hole 105, an indicator light hole 102, a switch hole 103, and a power plug hole 104 are processed on the side wall of the housing 1.

[0052] The indicator light hole 102 , the switch hole 103 and the power plug hole 104 are located on the same side wall of the housing 1 , and the light exit hole 105 is located on the other side wall.

[0053] The light exit hole 105 , the indicator light hole 102 and the switch hole 103 are located on the side wall at the corresponding position of the space A of the housing 1 .

[0054] The power plug hole 104 is located on the side wall at a position corresponding to the space B of the housing 1. The power plug hole 104 is used to insert a power connector. In this embodiment, the power plug hole 104 is a USB plug hole for connecting an external 24V adapter.

[0055] The upper cover plate 2 and the lower cover plate 3 are respectively mounted on the two end openings of the housing 1. The upper cover plate 2 and the lower cover plate 3 are used to seal the housing 1 to maintain a stable internal environment of the housing 1, thereby ensuring that the mode-locked fiber laser can operate stably for a long time.

[0056] In this embodiment, the dimensions of the shell are 140 mm×60 mm×40 mm (length×width×height).

[0057] The electrical components include: a laser adapter board 6, a circuit control board 4, a semiconductor laser driving board 5, an indicator light and a switch.

[0058] like Figure 5 As shown, the circuit control board 4 is located in the space A and is mounted on the inner wall of the housing 1 with the switch hole 103. The circuit control board 4 is electrically connected to the electrical plug hole 104, and the external power supply supplies power to the remaining electrical components in the mode-locked fiber laser through the circuit control board 4.

[0059] The switch is mounted on the circuit control board 4, and the switch is opposite to the switch hole 103; the switch extends out of the housing from the switch hole 103. The switch is electrically connected to the circuit control board 4 and is used to turn on or off the mode-locked fiber laser. In this embodiment, the switch is turned on or off by long pressing the switch, thereby avoiding a sudden change in current in the mode-locked fiber laser.

[0060] The indicator light is mounted on the circuit control board 4, and the indicator light is opposite to the indicator light hole 102; the indicator light extends out of the housing from the indicator light hole 102. The indicator light is electrically connected to the circuit control board 4, and is used to confirm the power supply status of the mode-locked fiber laser, and is also used to confirm whether the current reaches a preset value.

[0061] like Figure 2 and Figure 6 As shown, the semiconductor laser driving board 5 is located in the space B. The semiconductor laser driving board 5 is mounted on the lower end surface of the partition 101, and can also be mounted on the side wall of the housing. The semiconductor laser driving board 5 is electrically connected to the circuit control board 4 through the wire passing through the partition 101. The semiconductor laser driving board 5 is used to stably increase or decrease the current of the mode-locked fiber laser, thereby ensuring the stability of the semiconductor laser.

[0062] like Figure 3 and Figure 4 As shown, the laser adapter board 6 is located in the space A and is installed on the upper end surface of the partition 101. The laser adapter board 6 is located in the area A of the partition 101. The laser adapter board 6 is electrically connected to the semiconductor laser driving board 5 through the wire passing through the partition 101.

[0063] The optical device is located in the space A and is mounted on the upper end surface of the partition 101. Figure 3 and Figure 4 As shown, the optical device includes: a collimator 9, a half-wave plate 11, a polarization beam splitter 12, an optical isolator 13, PZT (abbreviation of lead zirconate titanate piezoelectric ceramic) 14, a semiconductor laser 7, a wavelength division multiplexer 8 and two 1 / 4 wave plates 10.

[0064] The collimator 9, the quarter wave plate 10, the half wave plate 11, the polarization beam splitter 12, the optical isolator 13, another quarter wave plate 10 and the PZT 14 are sequentially arranged in the region B of the partition 101 through the corresponding frames. The optical axes of the collimator 9, a quarter wave plate 10, the half wave plate 11, the polarization beam splitter 12, the optical isolator 13, another quarter wave plate 10 and the PZT 14 are aligned (i.e. coaxial). The light exit hole of the polarization beam splitter 12 is opposite to the light exit hole 105. The frame is used to support and adjust the optical device corresponding to it. In this embodiment, the frame of the polarization beam splitter 12 is fixed to the partition 101 by bonding, and the frames other than the frame of the polarization beam splitter 12 are fixed to the partition 101 by screws.

[0065] The semiconductor laser 7 is mounted on the laser adapter plate 6. The semiconductor laser 7 is electrically connected to the laser adapter plate 6. The semiconductor laser 7 is fastened to the laser adapter plate 6 by fasteners, so that the semiconductor laser 7 and the laser adapter plate 6 are tightly combined, which can ensure sufficient contact area, which is conducive to the heat transfer of the semiconductor laser 7 to the laser adapter plate 6, and the heat is transferred to the partition 101 through the laser adapter plate 6, and then transferred to the housing 1, thereby improving the heat dissipation effect and avoiding the influence of temperature on the locking mode stability.

[0066] The wavelength division multiplexer 8 is mounted on the partition 101 and is located in the area A of the partition 101. The wavelength division multiplexer 8 is connected to the semiconductor laser 7, the collimator 9 and the PZT 14 through optical fibers. The wavelength division multiplexer 8 is used to combine optical signals of different wavelengths into one beam.

[0067] In this embodiment, the material of the housing and the frame of the optical device is preferably aluminum, which can reduce the weight of the mode-locked fiber laser and make the mode-locked fiber laser easy to carry. Aluminum has high thermal conductivity, which helps to maintain a stable operating temperature inside the mode-locked fiber laser, thereby ensuring the optical stability of the mode-locked fiber laser.

[0068] Working principle:

[0069] Before locking mode starts:

[0070] After the mode-locked fiber laser is turned on, the indicator light turns red. At this time, the current of the semiconductor laser driver board rises steadily, and when the current of the laser driver board reaches the preset current value (that is, the power of the circuit meets the mode-locking requirement at this time), the indicator light turns green.

[0071] After the locking mode is started:

[0072] After the indicator light turns green, the mode locking is started, and the semiconductor laser 7 emits a laser beam. In this embodiment, the laser beam passes through the wavelength division multiplexer 8 and is successively transmitted to the collimator 9, a 1 / 4 wave plate 10, a half-wave plate 11, a polarization beam splitter 12, an optical isolator 13, another 1 / 4 wave plate 10 and PZT14 to complete the screening of the femtosecond mode-locked pulse mode, and finally achieve mode locking, thereby completing the self-starting of the mode-locked laser. The laser beam passes through the PZT14 and then returns to the wavelength division multiplexer 8. The semiconductor laser 7, the wavelength division multiplexer 8, the collimator 9, a 1 / 4 wave plate 10, a half-wave plate 11, a polarization beam splitter 12, an optical isolator 13, another 1 / 4 wave plate 10 and PZT14 form a ring cavity structure.

[0073] Among them, the collimator 9 is used to collimate the laser beam. Two 1 / 4 wave plates 10 and a half-wave plate 11 are used to adjust the polarization state of the laser beam. The polarization beam splitter 12 is used to export part of the polarized beam to the outside of the mode-locked fiber laser. The emitted laser beam is output to the outside of the housing through the light outlet 105. The emitted laser beam is used for subsequent measurement, etc. The unemitted laser continues to circulate in the ring cavity after passing through the polarizer of the polarization beam splitter 12. PZT14 is used to control the cavity length of the mode-locked fiber laser and lock the repetition frequency.

[0074] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A compact mode-locked fiber laser, characterized in that: include: A housing and optical and electrical components disposed inside the housing; The interior of the shell is divided into two spaces, space A and space B. The electrical components include: a laser adapter board, a circuit control board and a semiconductor laser driver board; The laser adapter board and the circuit control board are located in space A, and the semiconductor laser driver board is located in space B; The semiconductor laser driving board is electrically connected to the circuit control board; The laser adapter board is electrically connected to the semiconductor laser driver board; The optical devices are located in space A; the optical devices include: a collimator, a half-wave plate, a polarization beam splitter, an optical isolator, a PZT, a semiconductor laser, a wavelength division multiplexer and two quarter-wave plates; A collimator, a quarter wave plate, a half wave plate, a polarization beam splitter, an optical isolator, another quarter wave plate and a PZT are coaxially arranged in sequence inside the housing; The light exit hole of the polarization beam splitter is opposite to the light exit hole on the housing; The semiconductor laser is mounted on the laser adapter board, and the two are electrically connected; The wavelength division multiplexer is connected to the semiconductor laser, the collimator and the PZT through optical fibers respectively.

2. A compact mode-locked fiber laser as claimed in claim 1, characterized in that: A partition is provided inside the shell; The internal space of the shell is divided into space A and space B by a partition; The semiconductor laser driving board is mounted on the partition or the side wall of the housing; The laser adapter board, circuit control board, collimator, half-wave plate, polarization beam splitter, optical isolator, PZT, wavelength division multiplexer and two 1 / 4 wave plates are installed on the upper end surface of the partition.

3. A compact mode-locked fiber laser as claimed in claim 2, characterized in that: The upper end surface of the partition is divided into area A and area B; The semiconductor laser and the wavelength division multiplexer are located in area A of the partition; The collimator, two quarter wave plates, a half wave plate, a polarization beam splitter, an optical isolator and a PZT are located in region B of the partition.

4. A compact mode-locked fiber laser as claimed in claim 2, characterized in that: The circuit control board is located in the space A and is installed on the inner wall of the shell.

5. A compact mode-locked fiber laser as claimed in claim 4, characterized in that: The mode-locked fiber laser also includes: an indicator light and a switch; The indicator light and the switch are respectively mounted on the circuit control board, and the indicator light and the switch are respectively electrically connected to the circuit control board; The side wall surface of the housing on which the circuit control board is mounted is processed with an indicator light hole and a switch hole; The indicator light is opposite to the indicator light hole, and the indicator light extends out of the housing through the indicator light hole; The switch is opposite to the switch hole, and the switch extends out of the shell through the switch hole.

6. A compact mode-locked fiber laser as claimed in claim 1, characterized in that: The semiconductor laser is fastened and mounted on the laser adapter plate by fasteners.

7. A compact mode-locked fiber laser as claimed in claims 1 to 6, characterized in that: The housing comprises: an outer shell, an upper cover plate and a lower cover plate; The shell is open at both ends; the partition is arranged on the inner wall surface of the shell; the partition is parallel to the two open end surfaces of the shell; The upper cover plate and the lower cover plate are respectively mounted on the two opening ends of the shell.

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