A pump light source and an optical fiber amplifier composed of the same

Abstract

The present invention relates to a pump light source capable of simultaneously outputting single-mode and multi-mode light and an optical fiber amplifier composed thereof. The pump light source comprises a multi-mode pump laser, a coupler and a mode converter; the input end of the coupler is connected to the output end of the multi-mode pump laser, the first output end of the coupler is connected to the input end of the mode converter, the output end of the mode converter outputs single-mode pump light, and the second output end of the coupler outputs multi-mode pump light. The optical fiber amplifier comprises the pump light source and an amplifying optical path; the amplifying optical path comprises a primary amplifying optical path and a secondary amplifying optical path, the single-mode pump light output by the pump light source is connected to the primary amplifying optical path, and the signal light is amplified in the primary stage; the multi-mode pump light output by the pump light source is connected to the secondary amplifying optical path, and the signal light amplified in the primary stage is amplified in the secondary stage.

Description

Technical Field

[0001] The present invention relates to the technical field of optical fiber amplifiers, and in particular to a pump light source capable of simultaneously outputting single-mode and multi-mode light and an amplifier composed of the pump light source. Background Art

[0002] The current pump laser can only output pump light in either single-mode or multi-mode. When single-mode is output, core pumping is used, and the pump power is low; when multi-mode is output, the pump power is high, but it can only be applied to double-clad optical fibers with cladding pumping. In actual high-power erbium-doped fiber amplifiers, both single-mode pumping and multi-mode pumping are usually required.

[0003] At present, conventional high-power erbium-doped fiber amplifiers generally include a preamplifier stage and a power amplifier stage, such as Figure 1 As shown, the pre-amplifier stage uses the erbium-doped fiber 103 as the active fiber, uses the single-mode pump laser 108 for pumping, and the pumping method is core pumping. The signal light passes through the first optical isolator 101 to reach the wavelength division multiplexer 102. The pumping light output by the single-mode pump laser 108 directly enters the wavelength division multiplexer 102. The wavelength division multiplexer 102 couples the signal light and the pumping light and outputs them into the core of the erbium-doped fiber 103 to pre-amplify the signal light. The power amplifier stage after the pre-amplifier stage uses the erbium-ytterbium double-clad fiber 106 as the active light. The multimode pump laser 109 is used for pumping, and the pumping method is cladding pumping. The pre-amplified signal light reaches the pump coupler 105 through the second optical isolator 104. The pump light output by the multimode pump laser 109 directly enters the pump coupler 105. The pump coupler 105 couples the signal light to the core of the erbium ytterbium double-clad optical fiber 106 at the output end for transmission, and couples the pump light to the cladding of the erbium ytterbium double-clad optical fiber 106 at the output end for transmission. The signal light is further amplified and output from the output end 107. Therefore, the prior art needs to use two independent pump lasers to obtain single-mode and multi-mode pumping at the same time, resulting in high power consumption of the module, non-compact structure, and high cost. Summary of the invention

[0004] Based on this, an object of the present invention is to provide a pump light source that can output single-mode and multi-mode light simultaneously and an optical fiber amplifier composed of the pump light source.

[0005] The objective of the present invention is achieved through the following technical scheme: a pump light source, comprising a multi-mode pump laser, a coupler and a mode converter; the input end of the coupler is connected to the output end of the multi-mode pump laser, the first output end of the coupler is connected to the input end of the mode converter, the output end of the mode converter outputs single-mode pump light, and the second output end of the coupler outputs multi-mode pump light.

[0006] Compared with the prior art, the present invention organically combines a multi-mode pump laser, a coupler and a mode converter through reasonable design. The light output by the multi-mode pump laser is divided into two beams after passing through the coupler, one beam is used as a multi-mode pump light, and the other beam is converted into a single-mode pump light through the mode converter, so that only one multi-mode pump laser is needed to output single-mode and multi-mode pump light at the same time, making the structure of the pump light source more compact, reducing costs and reducing power consumption.

[0007] Furthermore, the multimode pump laser comprises a multimode pump chip and an output pigtail, and the output pigtail is a double-clad optical fiber.

[0008] Furthermore, the multi-mode pump laser is a 980nm multi-mode pump laser.

[0009] Furthermore, the splitting ratio between the first output end and the second output end of the coupler is 30 / 70.

[0010] The present invention also provides an optical fiber amplifier, comprising the pump light source and the amplification optical path described in the present invention; the amplification optical path comprises a primary amplification optical path and a secondary amplification optical path, the single-mode pump light output by the pump light source is connected to the primary amplification optical path, and the signal light is amplified in the primary stage; the multi-mode pump light output by the pump light source is connected to the secondary amplification optical path, and the signal light after the primary amplification is amplified in the secondary stage.

[0011] Compared with the prior art, the optical fiber amplifier of the present invention can simultaneously pump the two-stage amplification structure using a single pump light source, which can make up for the shortcomings of the existing structure and overcome the problems of high power consumption, low pump utilization, and insufficiently compact structure, as well as the use of a variety of pump lasers leading to complex driving and control.

[0012] Furthermore, the first-stage amplification optical path includes a first optical isolator, a wavelength division multiplexer and an erbium-doped optical fiber; the second-stage amplification optical path includes a second optical isolator, a combiner and a double-clad erbium-ytterbium co-doped optical fiber; the signal input end of the wavelength division multiplexer is connected to the output end of the first optical isolator, the pump input end of the wavelength division multiplexer is connected to the output end of the mode converter, and the output end of the wavelength division multiplexer is connected to the input end of the erbium-doped optical fiber; the input end of the second optical isolator is connected to the output end of the erbium-doped optical fiber; the signal input end of the combiner is connected to the output end of the second optical isolator, the pump input end of the combiner is connected to the second output end of the coupler, and the output end of the combiner is connected to the input end of the double-clad erbium-ytterbium co-doped optical fiber.

[0013] Furthermore, the optical fiber amplifier also includes a third optical isolator, and an input end of the third optical isolator is connected to an output end of the double-clad erbium-ytterbium co-doped optical fiber.

[0014] Furthermore, the wavelength division multiplexer is a 980 / 1550 wavelength division multiplexer.

[0015] Furthermore, the signal input end of the beam combiner is a single-mode optical fiber, the pump input end is a multi-mode optical fiber, and the output end is a double-clad optical fiber.

[0016] For better understanding and implementation, the present invention is described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the structure of an existing optical fiber amplifier.

[0018] Figure 2 FIG. 4 is a schematic diagram of the structure of a pump light source of an embodiment.

[0019] Figure 3 Schematic diagram of the structure of the optical fiber amplifier of the embodiment. DETAILED DESCRIPTION

[0020] Please also see Figure 2-3 , Figure 2 is a schematic diagram of the structure of the pump light source of this embodiment, Figure 3 Schematic diagram of the structure of the optical fiber amplifier of the embodiment.

[0021] The pump light source 200 of this embodiment includes a multi-mode pump laser 210, a coupler 220 and a mode converter 230. The input end of the coupler 220 is connected to the output end of the multi-mode pump laser 210, the first output end of the coupler 220 is connected to the input end of the mode converter 230, the output end of the mode converter 230 outputs single-mode pump light, and the second output end of the coupler 220 outputs multi-mode pump light.

[0022] Specifically, the multimode pump laser 210 is a 980nm multimode pump laser, which includes a multimode pump chip 211 and an output pigtail 212, and the output pigtail 212 is a double-clad optical fiber; the coupler 220 is insensitive to the mode, and the splitting ratio of the first output end and the second output end is 30 / 70; the mode converter 230 can convert the multimode pump light into a single-mode pump light. Therefore, after the pigtail is output, it is divided into two beams through the coupler, one beam is coupled into the multimode optical fiber as a multimode pump, and the other beam is converted into a single-mode light in the cladding through the mode converter and coupled into the single-mode optical fiber as a single-mode pump. The mode converter has no effect on the pump light originally transmitted by the core, and this part of the pump light can be directly coupled into the single-mode optical fiber.

[0023] The optical fiber amplifier of this embodiment includes a pump light source 200 and an amplifying optical path 300. The amplifying optical path 300 includes a primary amplifying optical path and a secondary amplifying optical path. The single-mode pump light output by the pump light source 200 is connected to the primary amplifying optical path to perform primary amplification on the signal light; the multi-mode pump light output by the pump light source 200 is connected to the secondary amplifying optical path to perform secondary amplification on the signal light after the primary amplification.

[0024] Specifically, the first-stage amplification optical path includes a first optical isolator 311, a wavelength division multiplexer 312 and an erbium-doped optical fiber 313; the second-stage amplification optical path includes a second optical isolator 321, a beam combiner 322 and a double-clad erbium-ytterbium co-doped optical fiber 323; the signal input end of the wavelength division multiplexer 312 is connected to the output end of the first optical isolator 311, the pump input end of the wavelength division multiplexer 312 is connected to the output end of the mode converter 230, and the wavelength division multiplexer 312 is connected to the output end of the mode converter 230. The output end of the optical coupler 312 is connected to the input end of the erbium-doped optical fiber 313; the input end of the second optical isolator 321 is connected to the output end of the erbium-doped optical fiber 313; the signal input end of the combiner 322 is connected to the output end of the second optical isolator 321, the pump input end of the combiner 322 is connected to the second output end of the coupler 220, and the output end of the combiner 322 is connected to the input end of the double-clad erbium-ytterbium co-doped optical fiber 323.

[0025] Specifically, the optical fiber amplifier further includes a third optical isolator 400 , and an input end of the third optical isolator 400 is connected to an output end of the double-clad erbium-ytterbium co-doped optical fiber 323 .

[0026] In this embodiment, the coupler 220 is a 30 / 70 coupler; the wavelength division multiplexer 312 is a 980 / 1550 wavelength division multiplexer; the signal input end of the combiner 322 is an ordinary G.652 optical fiber, the pump input end is a 105 / 125 multimode optical fiber, and the output end is an 8 / 125 double-clad optical fiber of OFS. The device can combine the single-mode signal light and the multi-mode pump light and inject them into the double-clad erbium-ytterbium co-doped optical fiber 323; the double-clad erbium-ytterbium co-doped optical fiber 323 is a 7 / 125 double-clad erbium-ytterbium co-doped optical fiber of OFS.

[0027] The specific connection mode and working principle of this embodiment are as follows:

[0028] The multi-mode pump light output by the 980nm multi-mode pump laser 210 is divided into two paths after passing through the 30 / 70 coupler 220, one path having a power of 30% of the total pump output and the other path having a power of 70% of the total pump output; the 30% output port of the 30 / 70 coupler 220 is connected to the mode converter 230 and is used as a single-mode pump after conversion by the mode converter 230; the 70% output port of the 30 / 70 coupler 220 is used as a multi-mode pump.

[0029] The signal light with a wavelength of 1550nm and a power of 0-10mW is inputted via the optical fiber jumper A, passes through the first optical isolator 311, and is connected to the 1550 port of the 980 / 1550 wavelength division multiplexer 312; at the same time, the output end of the mode converter 230 is connected to the 980 port of the 980 / 1550 wavelength division multiplexer 312; thus, the 980 / 1550 wavelength division multiplexer 312 inputs the 1550nm signal light and the 980nm single-mode pump light converted by the mode converter 230 into the core-pumped single-mode erbium-doped optical fiber 313, and the 980nm single-mode pump light is used as a pump to pre-amplify the 1550nm signal light, and the power of the pre-amplified signal light is 20-30mW.

[0030] The pre-amplified signal light passes through the second optical isolator 321 and enters the signal input end of the combiner 322; at the same time, the 70% output port of the 30 / 70 coupler 220 is connected to the pump input end of the combiner 322; thus, the combiner 322 combines the pre-amplified 1050nm signal light and the 980nm multimode pump light output through the 70% output port of the 30 / 70 coupler 220 and injects them into the double-clad erbium-ytterbium co-doped optical fiber 323, and the 980nm multimode pump light is used as a pump to further amplify the 1550nm signal light; the further amplified 1550nm signal light is output from the third optical isolator 400, and the output power of the final amplified signal light is 5 to 10W.

[0031] Compared with the prior art, the present invention organically combines a multi-mode pump laser, a coupler and a mode converter, and can realize that only one multi-mode pump laser is needed to simultaneously output single-mode and multi-mode pump light, and a single pump light source can be used to simultaneously pump a two-stage amplification structure, which can make up for the shortcomings of the existing structure and overcome the problems of high power consumption, low pump utilization, and insufficiently compact structure of the existing structure, as well as the complex driving and control caused by the use of a variety of pump laser types.

[0032] The above-mentioned embodiment only expresses one implementation mode of the present invention, and its description is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. An optical fiber amplifier, characterized in that: The invention comprises a pump light source and an amplifying optical path; the pump light source comprises a multimode pump laser, a coupler and a mode converter; the input end of the coupler is connected to the output end of the multimode pump laser, the first output end of the coupler is connected to the input end of the mode converter, the output end of the mode converter outputs single-mode pump light, and the second output end of the coupler outputs multimode pump light; the multimode pump laser comprises a multimode pump chip and an output pigtail, and the output pigtail is a double-clad optical fiber; the multimode pump light is divided into two beams through the coupler after passing through the output pigtail, one beam is coupled into the multimode optical fiber as a multimode pump, and the other beam converts the multimode light in the cladding into single-mode light through the mode converter and couples it into the single-mode optical fiber as a single-mode pump; the amplifying optical path comprises a primary amplifying optical path and a secondary amplifying optical path, and the pump The single-mode pump light output by the light source is connected to the primary amplification optical path to perform primary amplification on the signal light; the multi-mode pump light output by the pump light source is connected to the secondary amplification optical path to perform secondary amplification on the signal light after the primary amplification; the primary amplification optical path includes a first optical isolator, a wavelength division multiplexer and an erbium-doped optical fiber; the secondary amplification optical path includes a second optical isolator, a combiner and a double-clad erbium-ytterbium co-doped optical fiber; the wavelength division multiplexer inputs the signal light and the single-mode pump light converted by the mode converter into the core-pumped single-mode erbium-doped optical fiber together, and the single-mode pump light is used as a pump to perform primary amplification on the signal light; the combiner combines the signal light after the primary amplification and the multi-mode pump light output from the output port of the coupler and injects them into the double-clad erbium-ytterbium co-doped optical fiber, and the multi-mode pump light is used as a pump to perform secondary amplification on the signal light.

2. The optical fiber amplifier according to claim 1, characterized in that: The signal input end of the wavelength division multiplexer is connected to the output end of the first optical isolator, the pump input end of the wavelength division multiplexer is connected to the output end of the mode converter, and the output end of the wavelength division multiplexer is connected to the input end of the erbium-doped optical fiber; the input end of the second optical isolator is connected to the output end of the erbium-doped optical fiber; the signal input end of the combiner is connected to the output end of the second optical isolator, the pump input end of the combiner is connected to the second output end of the coupler, and the output end of the combiner is connected to the input end of the double-clad erbium-ytterbium co-doped optical fiber.

3. The optical fiber amplifier according to claim 2, characterized in that: The optical fiber amplifier further comprises a third optical isolator, the input end of the third optical isolator is connected to the output end of the double-clad erbium-ytterbium co-doped optical fiber.

4. The optical fiber amplifier according to claim 3, characterized in that: The wavelength division multiplexer is a 980 / 1550 wavelength division multiplexer.

5. The optical fiber amplifier according to claim 4, characterized in that: The signal input end of the beam combiner is a single-mode optical fiber, the pump input end is a multi-mode optical fiber, and the output end is a double-clad optical fiber.

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