CN207910227U - A kind of compound dual-cavity laser of all -fiber pulse - Google Patents

Abstract

The utility model discloses an all-fiber pulse composite double-cavity laser, which comprises a pumping source, a fiber combiner, a first gain fiber, a second gain fiber, a transition fiber, a first reflective fiber Bragg grating, and a second reflective fiber Bragg grating. Fiber Bragg grating, third reflective fiber Bragg grating, fourth reflective fiber Bragg grating, optical isolator, laser beam splitter. The utility model uses the optical fiber doped with rare earth elements as a gain medium and a saturable absorber, and at the same time uses a small-core-diameter gain fiber as the core of pulse generation to ensure single-mode operation, and a large-core-diameter gain fiber as a power amplifier, which can reduce nonlinearity effect, small core diameter and large core diameter optical fiber through the transition optical fiber to achieve mode field adaptation fusion is easy to bleach the inner cavity to obtain narrow pulse output; the utility model is also an all-fiber structure, with high stability, high power, high energy, high Features of efficiency.

Description

An all-fiber pulse-combined dual-cavity laser

technical field

The utility model belongs to the field of laser technology and nonlinear optics, in particular to an all-fiber pulse composite double-cavity laser

Background technique

High-power, high-energy pulsed fiber lasers are considered to be the development trend of future pulsed lasers due to their many advantages, and have gradually replaced traditional lasers in many fields. High-energy nanosecond pulsed fiber lasers are widely used in laser processing, optical time domain reflectometer (OTDR), second harmonic generation, military and other fields.

At present, in fiber lasers, there are generally two methods for obtaining pulse output: one is mode-locked fiber lasers, whose output pulse width is narrow, generally in the order of picoseconds or even femtoseconds; the second is Q-switched fiber lasers, Laser (giant pulse) output with nanosecond or submillisecond pulse width can be realized. Generally speaking, the traditional Q-switching method is realized by adding acousto-optic, electro-optic modulators or solid-state saturable absorbers. However, the combination of optical fibers and non-optical devices will increase the complexity of the system, affect system stability and anti-environmental interference, and is not conducive to Industrialization and practical promotion, so the realization of all-fiber high-energy and high-energy nanosecond pulsed fiber lasers is of great significance.

Utility model content

The problem to be solved by the utility model is to provide an all-fiber pulse compound dual-cavity laser in order to obtain nanosecond pulse output with high power, high energy and high beam quality, and avoid the use of space elements or additional modulators. The core diameter gain fiber is used as the core of pulse generation and ensures single-mode operation. The large core diameter gain fiber is used as a power amplifier, which can reduce the influence of nonlinear effects. The small core diameter and large core diameter fibers can achieve mode field adaptation and fusion splicing through transition fibers. Bleach lumen for narrow pulse output.

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

An all-fiber pulse compound dual-cavity laser, comprising: a pump source, a fiber combiner, a first gain fiber, a second gain fiber, a transition fiber, a first reflective fiber Bragg grating, a second reflective fiber Bragg grating, The third reflective fiber Bragg grating, the fourth reflective fiber Bragg grating, and the optical isolator; wherein, the pump source is connected to the pump input end of the fiber combiner; the signal end of the fiber combiner is connected to one end of the transition fiber ; The other end of the transition fiber is connected to one end of the first reflective fiber Bragg grating; the other end of the first reflective fiber Bragg grating is connected to one end of the first gain fiber; the other end of the first gain fiber is connected to the second reflective fiber Bragg One end of the grating; the other end of the second reflective fiber Bragg grating is connected to one end of the third reflective fiber Bragg grating; the common end of the fiber combiner is connected to one end of the second gain fiber; the other end of the second gain fiber is connected to the fourth One end of the reflective fiber Bragg grating; the third reflective fiber Bragg grating and the fourth reflective fiber Bragg grating form a first resonant cavity; the first reflective fiber Bragg grating and the second reflective fiber Bragg grating form a second resonant cavity; The pump light generated by the pump source enters the first resonant cavity through the pump input end of the fiber combiner, pumps the second gain fiber, and the formed laser passes through the fiber combiner, the first reflective fiber Bragg The grating enters the second resonant cavity, pumps the first gain fiber to generate another wavelength laser, and the other wavelength laser generated by the second resonant cavity passes through the fiber beam combiner, the second gain fiber, and the fourth reflective fiber Bragg in turn. Grating, optical isolator output.

Preferably, the reflectivity of the first reflective fiber Bragg grating, the second reflective fiber Bragg grating, the third reflective fiber Bragg grating, and the fourth reflective fiber Bragg grating are all R, wherein, 0<R< 1.

Preferably, the optical fiber combiner can be placed between the fourth reflective fiber Bragg grating and the optical isolator.

An all-fiber pulse compound dual-cavity laser, characterized in that it includes: a pump source, a fiber combiner, a first gain fiber, a second gain fiber, a transition fiber, a first reflective fiber Bragg grating, and a laser beam splitter , the fourth reflective fiber Bragg grating, an optical isolator; wherein, the pumping source is connected to the pumping input end of the fiber combiner; the signal end of the fiber combiner is connected to one end of the transition fiber; the other end of the transition fiber is connected to One end of the first gain fiber; the other end of the first gain fiber is connected to one end of the laser beam splitter; the other end of the laser beam splitter is directly connected to two output ports to form an optical ring; the common end of the fiber combiner is connected to the second gain fiber One end of the second gain fiber; the other end of the second gain fiber is connected to one end of the fourth reflective fiber Bragg grating; the laser beam splitter and the fourth reflective fiber Bragg grating form the first resonant cavity; the first reflective fiber Bragg grating and the laser beam splitter The pump constitutes the second resonant cavity; the pump light generated by the pump source enters the first resonant cavity through the pump input end of the fiber combiner, and pumps the second gain fiber, and the formed laser light passes through the fiber combiner , The first reflective fiber Bragg grating enters the second resonant cavity, pumps the first gain fiber to generate another wavelength laser, and the other wavelength laser generated by the second resonant cavity passes through the fiber combiner and the second gain fiber in turn , the fourth reflective fiber Bragg grating, optical isolator output.

Preferably, the reflectances of the first reflective fiber Bragg grating and the fourth reflective fiber Bragg grating are both R, wherein 0<R<1.

Preferably, the optical fiber combiner can be placed between the fourth reflective fiber Bragg grating and the optical isolator.

Preferably, the pump source is one of semiconductor lasers, solid lasers, gas lasers, fiber lasers, and Raman lasers, and the central wavelength range of the output pump light is: 700nm≤λ≤2000nm, the described The pumping method is one of core single-end pumping, fiber core double-end pumping, cladding single-end pumping, and cladding double-end pumping.

Preferably, the optical fiber combiner is a (2+1)×1 optical fiber combiner or a (6+1)×1 optical fiber combiner.

Preferably, the first gain fiber and the second gain fiber are polarization-maintaining fibers or photonic crystal polarization-maintaining fibers doped with rare earth elements, and the doped rare earth elements are ytterbium (Yb), erbium (Er), holmium One or more of (Ho), thulium (Tm), neodymium (Nd), chromium (Cr), samarium (Sm), and bismuth (Bi).

Preferably, the core diameter of the first gain fiber<the core diameter of the transition fiber<the core diameter of the second gain fiber.

Beneficial effect

The utility model resonator cross-modulated all-fiber pulse laser has the following advantages:

1. The utility model uses the optical fiber doped with rare earth elements as a gain medium and a saturable absorber, and does not require an additional external modulation source. It has an all-fiber structure, simple design, and low cost;

2. The utility model utilizes the cross-modulation function of the resonant cavity, and has higher output power and system stability than the traditional Q-switched laser;

3. The utility model is simple in design and compact in structure, and can output ultrashort pulse laser with high stability and large pulse energy, and is easy to realize industrialization.

4. The utility model uses doped optical fibers with different core diameters and transition optical fibers to match, and has greater energy and higher power output.

Description of drawings:

Fig. 1 is the basic schematic diagram of the all-fiber pulse compound dual-cavity laser of embodiment 1;

Fig. 2 is the basic schematic diagram of the all-fiber pulse compound dual-cavity laser of embodiment 2;

Fig. 3 is the basic schematic diagram of the all-fiber pulse compound dual-cavity laser of embodiment 3;

Fig. 4 is the basic schematic diagram of the all-fiber pulse compound dual-cavity laser of embodiment 4;

In the figure: 1. Pump source; 2. Fiber combiner; 3. First gain fiber; 4. Second gain fiber; 5. Transition fiber; 6. First reflective fiber Bragg grating; 7. Second reflective fiber Fiber Bragg grating; 8. The third reflective fiber Bragg grating; 9. The fourth reflective fiber Bragg grating; 10. Optical isolator; 0. Laser beam splitter;

Detailed ways

Below in conjunction with illustration 1, 2, 3, 4, the utility model will be further described, but not limited to the following several embodiments.

Example 1

The structure of an all-fiber pulse compound dual-cavity laser is shown in Figure 1. In the figure, 1 is the pump source, and a semiconductor laser diode with a center wavelength of 976nm can be selected; 2 is an optical fiber combiner, and a (2+1)×1 pump signal combiner can be selected, such as 20/125; 3 is Rare-earth-doped optical fiber can be ytterbium-doped optical fiber with a core diameter of 10 microns produced by Nufern in the United States; 4 is a rare-earth-doped optical fiber with a core diameter of 20 microns produced by Nufern in the United States; 5 is a transition fiber , the transmission fiber with a core diameter of 15 microns produced by Canada’s CoActive company can be selected; 6, 7, 8, and 9 are reflective fiber Bragg gratings, and high-inversion and partial reflection gratings are optional. The reflectivity is R, where 0 <R<1; 10 is an optical isolator, an optional polarization-independent optical isolator.

The pump light enters the second gain fiber 4 through the pump end of the fiber combiner 2, and then reaches the fourth reflective fiber Bragg grating 9, which is a high inversion grating, that is, the reflectivity R, R≥99 %, almost all the light at the central wavelength will be reflected back, through the second gain fiber 4, fiber combiner 2, transition fiber 5, first reflective fiber Bragg fiber 6, first gain fiber 3 and the second reflection Type fiber Bragg grating 7 reaches the third reflective fiber Bragg grating 8, the fiber Bragg grating is a total reflection type grating, that is, the reflectivity R, R≥99%, almost all the light at the central wavelength will be reflected back. The third reflective fiber Bragg grating 8 and the fourth reflective fiber Bragg grating 9 form the first resonant cavity. The laser light produced by the first resonator enters the first gain fiber 3 through the second reflective fiber Bragg grating 7, and then reaches the first reflective fiber Bragg grating 6, the first reflective fiber Bragg grating 7 and the second reflective fiber Bragg The grating 6 constitutes the second resonant cavity. Under the excitation of the pump source 1, the first resonant cavity first forms laser oscillation, and then pumps the second resonant cavity to output laser light of another wavelength, which passes through the transition fiber (5) and the fiber combiner (2) in turn. , the output of the second gain fiber (4), the fourth reflective fiber Bragg grating (9), and the optical isolator (10).

Example 2

An all-fiber pulse compound dual-cavity laser structure is shown in Figure 2, the basic structure is similar to Figure 1, and the pump source (1) and fiber combiner (2) are placed on the fourth reflective fiber Bragg grating (9) and the optical isolator (10).

Example 3

The structure of an all-fiber pulse compound dual-cavity laser is shown in Fig. 3 . 3 in the figure is the pump source, which can be a semiconductor laser diode with a center wavelength of 976nm; 2 is an optical fiber combiner, and a (2+1)×1 pump signal combiner can be used, such as 20/125 type; 3 is Rare-earth-doped optical fiber can be ytterbium-doped optical fiber with a core diameter of 10 microns produced by Nufern in the United States; 4 is a rare-earth-doped optical fiber with a core diameter of 20 microns produced by Nufern in the United States; 5 is a transition fiber , you can choose a transmission fiber with a core diameter of 15 microns produced by Canada's CoActive company; It can achieve the function of total reflection mirror; 6 and 9 are reflective fiber Bragg gratings, high reflection and partial reflection gratings are optional, and the reflectivity is R, where 0<R<1; 10 is an optical isolator, optional polarization Nothing to do with optoisolators.

The pump light enters the second gain fiber 4 through the pump end of the fiber combiner 2, and then reaches the fourth reflective fiber Bragg grating 9, which is a high inversion grating, that is, the reflectivity R, R≥99 %, almost all the light at the central wavelength will be reflected back, through the second gain fiber 4, the fiber combiner 2, the transition fiber 5, the first reflective fiber Bragg fiber 6, and reach the laser beam splitter 0, the fiber The Bragg grating is a full-reflection grating, that is, the reflectivity R, R≥99%, and almost all the light at the central wavelength will be reflected back. The laser beam splitter 0 and the fourth reflective fiber Bragg grating 9 form the first resonant cavity. The laser light generated by the first resonant cavity enters the first gain fiber 3 and then reaches the first reflective fiber Bragg grating 6. The laser beam splitter and the second reflective fiber Bragg grating 6 form the second resonant cavity. Under the excitation of the pump source 1, the first resonant cavity first forms laser oscillation, and then pumps the second resonant cavity to output laser light of another wavelength, which passes through the transition fiber (5) and the fiber combiner (2) in turn. , the output of the second gain fiber (4), the fourth reflective fiber Bragg grating (9), and the optical isolator (10).

Example 4

An all-fiber pulse compound dual-cavity laser structure is shown in Figure 4, the basic structure is similar to Figure 3, the pump source (1) and fiber combiner (2) are placed on the fourth reflective fiber Bragg grating (9) and the optical isolator (10).

Claims (8)

1. An all-fiber pulse composite dual-cavity laser, comprising: the device comprises a pumping source (1), an optical fiber combiner (2), a first gain optical fiber (3), a second gain optical fiber (4), a transition optical fiber (5), a first reflection type optical fiber Bragg grating (6), a second reflection type optical fiber Bragg grating (7), a third reflection type optical fiber Bragg grating (8), a fourth reflection type optical fiber Bragg grating (9) and an optical isolator (10); wherein,

the pump source (1) is connected with the pump input end of the optical fiber beam combiner (2); the signal end of the optical fiber combiner (2) is connected with one end of the transition optical fiber (5); the other end of the transition optical fiber (5) is connected with one end of a first reflection type fiber bragg grating (6); the other end of the first reflection type optical fiber Bragg grating (6) is connected with one end of the first gain optical fiber (3); the other end of the first gain fiber (3) is connected with one end of a second reflection type fiber Bragg grating (7); the other end of the second reflection type fiber Bragg grating (7) is connected with one end of a third reflection type fiber Bragg grating (8); the common end of the optical fiber combiner (2) is connected with one end of a second gain optical fiber (4); the other end of the second gain fiber (4) is connected with one end of a fourth reflection type fiber Bragg grating (9); the third reflection type fiber Bragg grating (8) and the fourth reflection type fiber Bragg grating (9) form a first resonant cavity; the first reflection type fiber Bragg grating (6) and the second reflection type fiber Bragg grating (7) form a second resonant cavity; pump light generated by a pump source (1) enters a first resonant cavity through a pump input end of an optical fiber beam combiner (2) to pump a second gain optical fiber (4), formed laser enters a second resonant cavity through the optical fiber beam combiner (2) and a first reflection type optical fiber Bragg grating (6), the first gain optical fiber (3) is pumped to generate laser with another wavelength, and the laser with another wavelength generated by the second resonant cavity is output through the optical fiber beam combiner (2), the second gain optical fiber (4), a fourth reflection type optical fiber Bragg grating (9) and an optical isolator (10) in sequence.

2. The all-fiber pulse composite dual-cavity laser as claimed in claim 1, wherein: the reflectivities of the first reflection type fiber Bragg grating (6), the second reflection type fiber Bragg grating (7), the third reflection type fiber Bragg grating (8) and the fourth reflection type fiber Bragg grating (9) are all R, wherein R is more than 0 and less than 1.

3. An all-fiber pulse composite dual-cavity laser, comprising: the device comprises a pumping source (1), an optical fiber beam combiner (2), a first gain optical fiber (3), a second gain optical fiber (4), a transition optical fiber (5), a first reflection type optical fiber Bragg grating (6), a laser beam splitter (0), a fourth reflection type optical fiber Bragg grating (9) and an optical isolator (10);

the pump source (1) is connected with the pump input end of the optical fiber beam combiner (2); the signal end of the optical fiber combiner (2) is connected with one end of the transition optical fiber (5); the other end of the transition optical fiber (5) is connected with one end of the first gain optical fiber (3); the other end of the first gain fiber (3) is connected with one end of the laser beam splitter; two output ends at the other end of the laser beam splitter are directly connected to form a light ring; the common end of the optical fiber combiner (2) is connected with one end of a second gain optical fiber (4); the other end of the second gain fiber (4) is connected with one end of a fourth reflection type fiber Bragg grating (9); the laser beam splitter (0) and the fourth reflection type optical fiber Bragg grating (9) form a first resonant cavity; the first reflection type fiber Bragg grating (6) and the laser beam splitter (7) form a second resonant cavity; pump light generated by a pump source (1) enters a first resonant cavity through a pump input end of an optical fiber beam combiner (2) to pump a second gain optical fiber (4), formed laser enters a second resonant cavity through the optical fiber beam combiner (2) and a first reflection type optical fiber Bragg grating (6), the first gain optical fiber (3) is pumped to generate laser with another wavelength, and the laser with another wavelength generated by the second resonant cavity is output through the optical fiber beam combiner (2), the second gain optical fiber (4), a fourth reflection type optical fiber Bragg grating (9) and an optical isolator (10) in sequence.

4. The all-fiber pulse composite dual-cavity laser as claimed in claim 3, wherein: the reflectivity of the first reflection type fiber Bragg grating (6) and the reflectivity of the fourth reflection type fiber Bragg grating (9) are both R, wherein R is more than 0 and less than 1.

5. The all-fiber pulse composite dual-cavity laser as claimed in claim 1 or 3, wherein: the pump source (1) is one of a semiconductor laser, a solid laser, a gas laser, a fiber laser and a Raman laser, and the range of the central wavelength of the output pump light is as follows: and lambda is more than or equal to 700nm and less than or equal to 2000nm, and the pumping mode is one of fiber core single-end pumping, fiber core double-end pumping, cladding single-end pumping and cladding double-end pumping.

6. The all-fiber pulse composite dual-cavity laser as claimed in claim 1 or 3, wherein: the optical fiber combiner (2) is a (2+1) x 1 optical fiber combiner or a (6+1) x 1 optical fiber combiner.

7. The all-fiber pulse composite dual-cavity laser device according to claim 1 or 3, wherein the first gain fiber (3) and the second gain fiber (4) are polarization maintaining fibers or photonic crystal polarization maintaining fibers doped with rare earth elements, and the doped rare earth elements are one or more of ytterbium Yb, erbium Er, holmium Ho, thulium Tm, Nd, chromium Cr, samarium Sm and bismuth Bi.

8. The all-fiber pulse composite dual-cavity laser as claimed in claim 1 or 3, wherein: the core diameter of the first gain fiber (3) is less than that of the transition fiber (5) and less than that of the second gain fiber (4).