阅读说明：本技术 一种环形泵浦光纤激光放大器 (Annular pump optical fiber laser amplifier ) 是由 雷敏 杨雨 武春风 *** 姜永亮 吕亮 刘厚康 宋祥 王光斗 胡阿健 戴玉芬 于 2020-06-12 设计创作，主要内容包括：本发明公开了一种环形泵浦光纤激光放大器,包括泵浦源、信号泵浦耦合器、增益光纤、泵浦滤除器,它们之间通过光纤熔接连,其特征在于所述信号泵浦耦合器为三个及以上,所述信号泵浦耦合器之间的泵浦臂通过光纤熔接连接,泵浦源发出的泵浦光通过信号泵浦耦合器进入增益光纤,未被吸收的大部分泵浦光由另一个信号泵浦耦合器的泵浦臂输出,将这部分输出的泵浦光通过信号泵浦耦合器再次注入增益光纤,循环吸收,由信号泵浦耦合器信号纤输出的泵浦光通过泵浦滤除器进行滤除。本发明能够将未吸收泵浦光进行循环吸收的光纤激光放大器方案,减少浪费的泵浦光功率,提高激光器斜率效率。(The invention discloses an annular pump optical fiber laser amplifier, which comprises a pump source, a signal pump coupler, a gain optical fiber and a pump filter, wherein the pump source, the signal pump coupler, the gain optical fiber and the pump filter are connected in a fusion mode through optical fibers. The invention can circularly absorb the unabsorbed pump light, reduce the wasted pump light power and improve the slope efficiency of the laser.)

1. An annular pumping optical fiber amplifier comprises a pumping source, signal pumping couplers, a gain optical fiber and a pumping filter, wherein the pumping source, the signal pumping couplers, the gain optical fiber and the pumping filter are connected through optical fiber fusion, the number of the signal pumping couplers is three or more, pumping arms among the signal pumping couplers are connected through the optical fiber fusion,

the pump light emitted by the pump source enters the gain fiber through the signal pump coupler, most of the unabsorbed pump light is output by the pump arm of the other signal pump coupler, the pump light output by the part of the unabsorbed pump light is injected into the gain fiber again through the signal pump coupler, the pump light is circularly absorbed, and the pump light output by the signal fiber of the signal pump coupler is filtered through the pump filter.

2. The ring pumped fiber amplifier of claim 1, wherein said signal pump coupler is of a conventional (6+1) x 1, (2+1) x 1 configuration, or of other pump configurations.

3. The ring pumped fiber amplifier according to claim 2, wherein the optical fiber used in said signal pump coupler is any passive fiber matched to the gain fiber.

4. Ring pumped fiber amplifier according to claim 3, wherein the gain fiber is a section of fiber or several sections of different kinds and lengths of fiber.

5. The ring-pumped optical fiber amplifier according to claim 4, wherein the number of the signal pump couplers is three, specifically two forward signal pump couplers and one backward signal pump coupler, and the forward signal pump couplers are led out from the signal pump couplers by one optical fiber after entering the signal pump couplers from a plurality of optical fibers along the signal light transmission direction with respect to the signal light transmission direction; the reverse signal pump coupler is relative to the signal light transmission direction, and is led out from the signal pump coupler by a plurality of optical fibers after entering the signal pump coupler by one optical fiber along the signal light transmission direction;

the device comprises a plurality of pumping sources, two forward signal pumping couplers, a section of gain fiber, a reverse signal pumping coupler and a pumping light filter, wherein the direction from the two forward signal pumping couplers to the reverse signal pumping coupler is a signal light transmission direction, the pumping sources, the two forward signal pumping couplers, the gain fiber, the reverse signal pumping coupler and the pumping light filter are sequentially connected through fiber fusion, and the pumping arms of the forward signal pumping coupler and the reverse signal pumping coupler are connected through fiber fusion;

the pumping light emitted by the pumping source is injected into the gain fiber through two forward signal pumping couplers, one part of the pumping light is absorbed by the gain fiber, the other part of the pumping light is output through the signal fiber and the pumping fiber of the backward signal pumping coupler, the part of the pumping light output by the pumping fiber is injected into the gain fiber again through one forward signal pumping coupler for circular absorption, and the output light of the signal fiber of the backward signal pumping coupler is filtered by the pumping filter to remove the cladding light so as to realize signal laser output.

6. The ring-pumped optical fiber amplifier according to claim 4, wherein the number of the signal pump couplers is three, specifically two backward signal pump couplers and one forward signal pump coupler, and the forward signal pump coupler is led out from the signal pump coupler by one optical fiber after entering the signal pump coupler by a plurality of optical fibers along the signal light transmission direction with respect to the signal light transmission direction; the reverse signal pump coupler is relative to the signal light transmission direction, and is led out from the signal pump coupler by a plurality of optical fibers after entering the signal pump coupler by one optical fiber along the signal light transmission direction;

the device comprises a plurality of pumping sources, two reverse signal pumping couplers, a section of gain fiber, a forward signal pumping coupler and two pumping light filters, wherein the direction from the two reverse signal pumping couplers to the forward signal pumping coupler is a signal light transmission direction, the pumping sources, the two reverse signal pumping couplers, the gain fiber, the forward signal pumping coupler and the two pumping light filters are sequentially connected through fiber fusion, and the reverse signal pumping coupler is connected with a pumping arm of the forward signal pumping coupler through fiber fusion;

the pump light emitted by the pump source is injected into the gain fiber through the two reverse signal pump couplers, one part of the pump light is absorbed by the gain fiber, the other part of the pump light is output through the signal fiber and the pump fiber of the forward signal pump coupler, the part of the pump light output by the pump fiber is injected into the gain fiber again through one reverse signal pump coupler for cyclic absorption, the pump light output by the signal fiber of the forward signal pump coupler is filtered by the pump filter, and the signal laser output is realized after the cladding light is filtered by the pump filter.

7. The ring-pumped optical fiber amplifier according to claim 4, wherein the number of the signal pump couplers is three, specifically two forward signal pump couplers and one backward signal pump coupler, and the forward signal pump couplers are led out from the signal pump couplers by one optical fiber after entering the signal pump couplers from a plurality of optical fibers along the signal light transmission direction with respect to the signal light transmission direction; the reverse signal pump coupler is relative to the signal light transmission direction, and is led out from the signal pump coupler by a plurality of optical fibers after entering the signal pump coupler by one optical fiber along the signal light transmission direction;

the device comprises a first pump source group and a second pump source group which are composed of a plurality of pump sources, two forward signal pump couplers, two sections of gain fibers, a reverse signal pump coupler and a pump light filter, wherein the direction from the two forward signal pump couplers to the reverse signal pump coupler is a signal light transmission direction, the first pump source group and the second pump source group, the forward signal pump coupler, the two sections of gain fibers, the reverse signal pump coupler and the pump light filter are sequentially connected through fiber fusion, and the pump arms of the forward signal pump coupler and the reverse signal pump coupler are connected through fiber fusion;

the pumping light emitted by the pumping source of the first pumping source group is injected into the gain fiber through the forward signal pumping coupler, one part of the pumping light is absorbed by the gain fiber, the rest pumping light and the pumping light output by the second pumping source group are injected into the gain fiber through the forward signal pumping coupler, one part of the pumping light is absorbed by the gain fiber, the other part of the pumping light is output through the signal fiber and the pumping fiber of the backward signal pumping coupler, the part of the pumping light output by the pumping fiber is injected into the two sections of gain fibers again through the two forward signal pumping couplers for circular absorption, and the output light of the signal fiber of the backward signal pumping coupler is filtered by the pumping filter to remove the cladding light so as to realize signal laser output.

Technical Field

The invention belongs to the technical field of optical fiber laser amplifiers, and particularly relates to an annular pumping optical fiber laser amplifier.

Background

In the high-power optical fiber laser amplifier, the power of optical fiber transmission is high, the sectional area of a fiber core is small, the interaction distance of transmitted light in the optical fiber is very long, and the nonlinear effects such as SBS, SRS, FWM and the like are easily generated in the laser amplification process. The SBS and the SRS are two main factors influencing the output laser power, the threshold values of the SBS and the SRS are in inverse proportion to the length of the optical fiber, and in the process of laser development, in order to inhibit the nonlinear effects and improve the nonlinear threshold values, the length of the gain optical fiber needs to be shortened as much as possible. However, since the absorption coefficient of the gain fiber to the pump light is constant, when the length of the gain fiber is too short, a large amount of pump light power cannot be sufficiently absorbed, which causes energy waste, increases the system heat dissipation requirement, and reduces the efficiency of the laser; moreover, the pump light which can not be absorbed sufficiently can also increase the index requirement of the cladding light filter, and increase the manufacturing cost of the system.

Disclosure of Invention

In order to solve the problems, a scheme of the optical fiber laser amplifier for circularly absorbing the unabsorbed pump light is provided, so that the wasted pump light power is reduced, and the slope efficiency of the laser is improved.

The invention relates to an annular pump optical fiber laser amplifier, which comprises a pump source, signal pump couplers, a gain optical fiber and a pump filter, wherein the pump source, the signal pump couplers, the gain optical fiber and the pump filter are connected through optical fiber fusion, the number of the signal pump couplers is three or more, the pump fibers among the signal pump couplers are connected through optical fiber fusion,

the pump light emitted by the pump source enters the gain fiber through the signal pump coupler, most of the unabsorbed pump light is output by the pump fiber of the other signal pump coupler, the output pump light is injected into the gain fiber again through the signal pump coupler for cyclic absorption, and the pump light output by the signal fiber of the signal pump coupler is filtered through the pump filter.

Specifically, the signal pumping coupler is a conventional (6+1) × 1, (2+1) × 1 structure, or a (18+1) × 1, (1+1) × 1 structure, or other (N +1) × 1 pumping structures, and N is a natural number.

In particular, the optical fiber used by the signal pump coupler is any passive optical fiber matched with the gain optical fiber.

The optical fiber used by the signal pump coupler comprises a signal fiber and a pump fiber, wherein the signal fiber is a double-clad optical fiber with 10/125, 25/400 and 30/250 in various sizes, and the pump fiber is a single-clad or double-clad optical fiber with 105/125, 200/220 and 220/242 in various sizes.

Optionally, the gain fiber is a section of fiber, or several sections of fibers of different kinds and lengths.

Preferably, the number of the signal pump couplers is three, specifically, two forward signal pump couplers and one backward signal pump coupler, and the forward signal pump couplers are, with respect to the signal light transmission direction, led out from the signal pump couplers by one optical fiber after entering the signal pump couplers from a plurality of optical fibers along the signal light transmission direction; the reverse signal pump coupler is relative to the signal light transmission direction, and is led out from the signal pump coupler by a plurality of optical fibers after entering the signal pump coupler by one optical fiber along the signal light transmission direction;

the device comprises a plurality of pumping sources, two forward signal pumping couplers, a section of gain fiber, a reverse signal pumping coupler and a pumping light filter, wherein the direction from the two forward signal pumping couplers to the reverse signal pumping coupler is a signal light transmission direction, the pumping sources, the two forward signal pumping couplers, the gain fiber, the reverse signal pumping coupler and the pumping light filter are sequentially connected through fiber fusion, and the forward signal pumping coupler and the pumping fiber of the reverse signal pumping coupler are connected through fiber fusion;

the pumping light emitted by the pumping source is injected into the gain fiber through two forward signal pumping couplers, one part of the pumping light is absorbed by the gain fiber, the other part of the pumping light is output through the signal fiber and the pumping fiber of the backward signal pumping coupler, the part of the pumping light output by the pumping fiber is injected into the gain fiber again through one forward signal pumping coupler for circular absorption, and the output light of the signal fiber of the backward signal pumping coupler is filtered by the pumping filter to remove the cladding light so as to realize signal laser output.

Preferably, the number of the signal pump couplers is three, specifically, two backward signal pump couplers and one forward signal pump coupler, and the forward signal pump coupler is, with respect to the signal light transmission direction, led out from the signal pump coupler by one optical fiber after entering the signal pump coupler from a plurality of optical fibers along the signal light transmission direction; the reverse signal pump coupler is relative to the signal light transmission direction, and is led out from the signal pump coupler by a plurality of optical fibers after entering the signal pump coupler by one optical fiber along the signal light transmission direction;

the device comprises a plurality of pumping sources, two reverse signal pumping couplers, a section of gain fiber, a forward signal pumping coupler and two pumping light filters (6,9), wherein the direction from the two reverse signal pumping couplers to the forward signal pumping coupler is a signal light transmission direction, the pumping sources, the two reverse signal pumping couplers, the section of gain fiber, the forward signal pumping coupler and the two pumping light filters (6,9) are sequentially connected through fiber fusion, and the reverse signal pumping coupler is connected with the pumping fiber of the forward signal pumping coupler through fiber fusion;

the pump light emitted by the pump source is injected into the gain fiber through the two reverse signal pump couplers, one part of the pump light is absorbed by the gain fiber, the other part of the pump light is output through the signal fiber and the pump fiber of the forward signal pump coupler, the part of the pump light output by the pump fiber is injected into the gain fiber again through one reverse signal pump coupler for cyclic absorption, the pump light output by the signal fiber of the forward signal pump coupler is filtered by the pump filter, and the signal laser output is realized after the cladding light is filtered by the pump filter.

Preferably, the number of the signal pump couplers is three, specifically, two forward signal pump couplers and one backward signal pump coupler, and the forward signal pump couplers are, with respect to the signal light transmission direction, led out from the signal pump couplers by one optical fiber after entering the signal pump couplers from a plurality of optical fibers along the signal light transmission direction; the reverse signal pump coupler is relative to the signal light transmission direction, and is led out from the signal pump coupler by a plurality of optical fibers after entering the signal pump coupler by one optical fiber along the signal light transmission direction;

the device comprises a first pump source group and a second pump source group which are composed of a plurality of pump sources, two forward signal pump couplers, two sections of gain fibers, a reverse signal pump coupler and a pump light filter, wherein the direction from the two forward signal pump couplers to the reverse signal pump coupler is a signal light transmission direction, the first pump source group and the second pump source group, the forward signal pump coupler, the two sections of gain fibers, the reverse signal pump coupler and the pump light filter are sequentially connected through fiber fusion, and the forward signal pump coupler and the pump fibers of the reverse signal pump coupler are connected through fiber fusion;

the pumping light emitted by the pumping source of the first pumping source group is injected into the gain fiber through the forward signal pumping coupler, one part of the pumping light is absorbed by the gain fiber, the rest pumping light and the pumping light output by the second pumping source group are injected into the gain fiber through the forward signal pumping coupler, one part of the pumping light is absorbed by the gain fiber, the other part of the pumping light is output through the signal fiber and the pumping fiber (10) of the backward signal pumping coupler, the part of the pumping light output by the pumping fiber (10) is injected into the two sections of gain fibers through the two forward signal pumping couplers for cyclic absorption, and the output light of the signal fiber of the backward signal pumping coupler is filtered by the pumping filter to remove the cladding light, so that the output of the signal laser is realized.

The ring-shaped pumping optical fiber laser amplifier provided by the invention has the following advantages:

1. the unabsorbed pump light is circularly absorbed, so that the wasted pump light power is reduced, and the slope efficiency of the laser is improved;

2. the optical path length is reduced under the condition of keeping the absorption of the pump light unchanged, and the nonlinear effect of the optical fiber is favorably inhibited;

3. the combination of gain fiber segmented pumping reduces the heat density in the fiber, and is beneficial to inhibiting the mode instability effect of the fiber laser amplifier.

In summary, the present invention utilizes the characteristic that the pump light is output from the pumping fiber of the signal pumping coupler, and uses a plurality of forward and backward signal pumping couplers to realize the reuse of the pump light, which is favorable for reducing the wasted pump light power and improving the slope efficiency of the laser.

Drawings

FIG. 1 is a schematic diagram and an optical path structure of the present invention using a backward signal pump coupler to extract unabsorbed pump light and re-inject the unabsorbed pump light into a gain fiber by a forward pump coupler;

FIG. 2 is a schematic diagram and an optical path structure of the present invention using a forward signal pump coupler to extract unabsorbed pump light and re-inject the unabsorbed pump light into a gain fiber by a backward pump coupler;

fig. 3 is a schematic diagram of an optical path structure in which unabsorbed pump light and new pump light are injected into a next section of gain fiber through a forward signal pump coupler by using a segmented pumping gain fiber, the unabsorbed pump light is guided out by a reverse signal pump coupler, and the pump light is injected into the gain fiber again by an idle pump fiber of the forward pump coupler;

in the figure, 1-a plurality of pump sources, 1 a-a first pump source group, 1 b-a second pump source group, 2-a forward signal pump coupler, 4-a gain fiber, 5-a reverse signal pump coupler, 6-a pump light filter, 7-a signal fiber and 8-a pump fiber.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention are further described below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not to be construed as limiting the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.