All-fiber annular Mmyshev laser

Abstract

The invention discloses an all-fiber annular Mmyshev laser, a first part comprises a first Mmyshev oscillator, a first high-nonlinearity optical fiber and a first pump light generation module, a second part comprises a second Mmyshev, a second high-nonlinearity optical fiber and a second pump light generation module, the first high-nonlinearity optical fiber is connected with a second Mmyshev oscillator through a first filtering isolation coupler, the second high-nonlinearity optical fiber is connected with a second pump light generation module through a second filtering isolation coupler, and the second high-nonlinearity optical fiber is connected with a second pump light generation module through a second filtering isolation coupler. And the second high-nonlinearity optical fiber is connected with the first Mmyshev oscillator through the second filtering isolation coupler, so that the two parts are closed to form an annular cavity structure. The ultra-short pulse laser has the advantages of longer service life, higher output polarization and more compact structure, and ultra-short pulse output can be realized only by adjusting the length of the high-nonlinearity optical fiber in the oscillator on the premise of not increasing the pumping light power.

Description

Technical Field

[0001] The invention belongs to the technical field of lasers and relates to an all-fiber ring Mamyshev laser. Background Art

[0002] Ultrashort pulse lasers can achieve the characteristics of short pulse duration, high repetition rate, and large single pulse energy. They have been widely used in cutting-edge fields such as medicine and quantum, and there is still a broader market space. Among the commonly used lasers, fiber lasers are favored because of their compact structure, good robustness, low cost, and high repeatability of manufacturing processes. Pulsed light is generated by mode locking. Mode-locked lasers are divided into two categories: active mode locking and passive mode locking. Compared with the active mode-locked laser pump light generation module, the passive mode-locked laser can output ultrashort pulses without adding any modulator in the cavity. The mode locking is achieved by using the nonlinear effect or saturable absorber in the optical fiber. The implementation scheme of this principle is easier to be compatible with optical fibers. If the splitting ratio of the mode-locked fiber laser based on the nonlinear effect is not accurately controlled, it will cause pulse splitting; and the saturable absorber will have a short service life due to its low damage threshold.

[0003] Therefore, the introduction of Mamyshev oscillator (MO) in optical fiber to limit pulse splitting and the high damage threshold of the device have attracted widespread attention. Its principle is to achieve pulse broadening and spectral filtering compensation through self-phase modulation transfer effect and then achieve self-amplitude modulation effect, which is the same as the effect of saturable absorber. The introduction of this structure can realize the optical path of the all-fiber structure to withstand high nonlinear effects and achieve large output pulse energy.

[0004] The related solutions in the prior art can achieve pulse broadening through passive optical fiber, but it still cannot meet the requirements of achieving high-power pulse energy output. If the pump efficiency is directly improved, it will directly increase the burden on the optical components in the system and thus damage the optical path. Summary of the invention

[0005] Therefore, the present invention provides an all-fiber ring passive mode-locked laser, which introduces a Mamyshev oscillator to limit pulse splitting and improve the damage threshold, thereby solving the problem that the pulse energy cannot be obtained due to the limitation of the nonlinear effect on the pulse energy in the resonant cavity.

[0006] The technical solution adopted by the present invention to solve the technical problem is: an all-fiber ring Mamyshev laser, the first part includes a first Mamyshev oscillator and a first high nonlinear optical fiber connected to the first Mamyshev oscillator through a first three-port combiner, the first combiner is connected to the first Mamyshev oscillator and the first high nonlinear optical fiber through two ports, the first combiner is connected to a first pump light generating module through a third port, the second part includes a second Mamyshev oscillator and a second high nonlinear optical fiber connected to the second Mamyshev oscillator through a second three-port combiner, the second combiner is connected to the second Mamyshev oscillator and the second high nonlinear optical fiber through two ports, the second combiner is connected to the second pump light generating module through the third port, the first high nonlinear optical fiber is connected to the second Mamyshev oscillator through a first filter isolation coupler, and the second high nonlinear optical fiber is connected to the first Mamyshev oscillator through a second filter isolation coupler, so that the two parts complete a closed loop to form a ring cavity structure.

[0007] Furthermore, the first filter isolation coupler and the second filter isolation coupler are 1x2 fiber couplers, which combine the optical signal and the pump light into one beam and then send it into the first high nonlinear optical fiber and the second high nonlinear optical fiber for amplification.

[0008] Furthermore, a chirped fiber grating is provided at an output end of the first filter isolation coupler or / and the second filter isolation coupler.

[0009] Furthermore, the first high nonlinear optical fiber and the second high nonlinear optical fiber are both quartz optical fibers, which are generally applicable to nonlinear effects excited by different pump energies.

[0010] Furthermore, the first high nonlinear optical fiber and the second high nonlinear optical fiber are rare earth doped special optical fibers such as erbium and ytterbium co-doped optical fibers, which can amplify optical signals.

[0011] The beneficial effects of the present invention are as follows: the present invention adopts an all-fiber device, has a longer service life, higher output polarization, and a more compact structure. Under the premise of not increasing the pump light power, ultrashort pulse output can be achieved only by adjusting the length of the oscillator and the highly nonlinear optical fiber. This will be beneficial to the potential development needs in the fields of optical communications and laser micromachining, and is of great significance for subsequent research. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural schematic diagram of the present invention.

[0013] The figures are marked as follows: 1—first beam combiner, 2—first pump light generating module, 3—first highly nonlinear optical fiber, 4—first Mamyshev oscillator, 5—first filter isolation coupler, 6—second beam combiner, 7—second pump light generating module, 8—second highly nonlinear optical fiber, 9—second Mamyshev oscillator, 10—second filter isolation coupler. DETAILED DESCRIPTION

[0014] In order to better illustrate the design concept and technical solution of the structured laser, the implementation mode of the present invention is further described below in conjunction with the accompanying drawings.

[0015] Reference Figure 1 As shown, the present invention discloses an all-fiber ring Mamyshev laser, which has two parts: the first part includes a first Mamyshev oscillator 4, a three-port first combiner 1 and a first high nonlinear optical fiber 3 connected in sequence, the port 1-1 of the first combiner 1 is connected to the first pump light generating module 2, and the ports 1-3 and 1-2 of the first combiner 1 are respectively connected to the first Mamyshev oscillator 4 and the first high nonlinear optical fiber 3; the second part includes a second Mamyshev oscillator 9, a three-port second combiner 6 and a second high nonlinear optical fiber 8 connected in sequence, the ports 6-1 and 6-3 of the second combiner 6 are respectively connected to the second high nonlinear optical fiber 8 and the second Mamyshev oscillator 9, the port 6-2 of the second combiner 6 is connected to the second pump light generating module 7, the first high nonlinear optical fiber 3 is connected to the second Mamyshev oscillator 9 through the first filter isolation coupler 5, and the second high nonlinear optical fiber 8 is connected to the first Mamyshev oscillator 4 through the second filter isolation coupler 10, so that the two parts complete the closed loop to form a ring cavity structure.

[0016] The first high nonlinear optical fiber 3 and the second high nonlinear optical fiber 8 are single-mode optical fibers, which provide gain and have a larger output power. Moreover, both are quartz optical fibers and are generally applicable to nonlinear effects excited by different pump energies.

[0017] The first part of the present invention is connected in series with a first high nonlinear optical fiber 3, a first filtering isolation coupler 5 and a second Mamyshev oscillator 9. After the light is transmitted from two directions through a loop, it is continuously filtered in the oscillator to increase the pulse energy, thereby making it easier for the intracavity loop light to generate giant pulses; the second part of the present invention is connected in series with a second high nonlinear optical fiber 8, a second filtering isolation coupler 10 and a first Mamyshev oscillator 4. After the light is transmitted from two directions through a loop, it is continuously filtered in the oscillator to increase the pulse energy, thereby making it easier for the intracavity loop light to generate giant pulses; the two parts of the optical path are processed by optical fiber fusion.

[0018] The first filter isolation coupler 5 and the second filter isolation coupler 10 added to the ring cavity structure of the present invention are 1x2 fiber couplers, which ensure unidirectional operation of the laser to ensure stable transmission of the laser. The 1x2 fiber coupler combines the optical signal and the pump light into one beam and sends it to the first high nonlinear optical fiber 3 and the second high nonlinear optical fiber 8 for amplification. The coupler with an asymmetric fiber coupler splitting ratio pump light generation module (pump light generation module is 99:1, 98:2, 97:3 pump light generation module or any other asymmetric splitting ratio pump light generation module) can be preferred.

[0019] The first high nonlinear optical fiber 3 and the second high nonlinear optical fiber 8 of the present invention are rare earth doped special optical fibers such as erbium and ytterbium co-doped, and can amplify optical signals.

[0020] Some alternatives use a non-reciprocal optical element placed at one end of the loop to change the amount of nonlinear phase shift accumulated when the light propagates in the cavity.

[0021] Optionally, a chirped fiber grating is selected at the output end of the first filter isolation coupler 5 and the second filter isolation coupler 10, so that the generated mode-locked light can be compressed at the grating and then enter the cavity as signal light and then be amplified and output.

[0022] The above embodiments are only illustrative of the principles and effects of the present invention, as well as some embodiments of its application. For those skilled in the art, several modifications and improvements may be made without departing from the creative concept of the present invention, and all of these belong to the protection scope of the present invention.

Claims

1. An all-fiber ring Mamyshev laser, characterized in that: The invention comprises a first Mamyshev oscillator (4) and a first high nonlinear optical fiber (3) connected to the first Mamyshev oscillator (4) through a first three-port combiner (1), the first combiner (1) being connected to the first Mamyshev oscillator (4) and the first high nonlinear optical fiber (3) through two ports respectively, the first combiner (1) being connected to a first pump light generating module (2) through a third port, and further comprises a second Mamyshev oscillator (9) and a second high nonlinear optical fiber (8) connected to the second Mamyshev oscillator (9) through a second three-port combiner (6), the second combiner (6) being connected to the second Mamyshev oscillator (9) and the second high nonlinear optical fiber (8) through two ports respectively, the second combiner (6) being connected to a second pump light generating module (7) through a third port, the first high nonlinear optical fiber (3) being connected to the second Mamyshev oscillator (9) through a first filter isolation coupler (5), and the second high nonlinear optical fiber (8) being connected to the first Mamyshev oscillator (4) through a second filter isolation coupler (10).

2. The all-fiber ring Mamyshev laser according to claim 1, characterized in that: The first filtering isolation coupler (5) and the second filtering isolation coupler (10) are 1x2 optical fiber couplers.

3. The all-fiber ring Mamyshev laser according to claim 1, characterized in that: The output end of the first filtering isolation coupler (5) or / and the second filtering isolation coupler (10) is provided with a chirped fiber grating.

4. An all-fiber ring Mamyshev laser according to claim 1, 2 or 3, characterized in that: The first high nonlinear optical fiber (3) and the second high nonlinear optical fiber (8) are quartz optical fibers.

5. The all-fiber ring Mamyshev laser according to claim 4, characterized in that: The first high nonlinear optical fiber (3) and the second high nonlinear optical fiber (8) are erbium-ytterbium co-doped rare earth-doped special optical fibers.

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