A supercontinuum light source based on random lasing

Abstract

The present invention provides a supercontinuum light source based on random laser, which includes a pump source, a beam combiner, a gain fiber, a first long-distance single-mode communication fiber, a total output end, and a random laser reflection module. The first long-distance single-mode communication fiber is used to generate supercontinuum fiber laser, and the random laser reflection module is used to reduce the threshold of random laser. The output end of the pump source and the output end of the random laser reflection module are both connected to the input end of the beam combiner. The output end of the beam combiner, the gain fiber, the first long-distance single-mode communication fiber, and the total output end are connected in sequence. The supercontinuum spectrum is generated based on the fiber random laser technology, with a simple and reliable structure, and it can effectively avoid the loss of the supercontinuum light source during fiber transmission. By using the first long-distance single-mode communication fiber, it has good compatibility and excellent beam quality. The lasing threshold of the random laser is reduced through the random laser reflection module, the supercontinuum threshold is reduced, and the practicability is enhanced.

Description

Technical Field

[0001] The present invention relates to the field of optical communication, and particularly to a supercontinuum light source based on random laser. Background Art

[0002] Supercontinuum light sources have wide applications in national defense and military, scientific research, optical detection, and spectral analysis. However, currently, most mature supercontinuum solutions are based on ultrafast pulsed laser amplification. High-peak-power short-pulse lasers are used to excite photonic crystal fibers to achieve supercontinuum generation. The supercontinuum light sources with this structure have high costs, poor compatibility with photonic crystal fibers, and low system operation efficiency. There are also supercontinuum solutions based on continuous light. High-power pump lasers are injected into photonic crystal fibers or conventional single-mode fibers, and supercontinuum generation is excited near the zero-dispersion point of the fiber. The supercontinuum light sources with this structure have high generation thresholds and low practicality. Summary of the Invention

[0003] Aiming at the defects of high cost of supercontinuum light sources, poor compatibility with photonic crystal fibers, high supercontinuum thresholds, and low practicality in the prior art, the present invention provides a supercontinuum light source based on random laser.

[0004] A supercontinuum light source based on random laser of the present invention includes a pump source, a beam combiner, a gain fiber, a first long-distance single-mode communication fiber, a total output end, and a random laser reflection module. The first long-distance single-mode communication fiber is used to generate supercontinuum spectral fiber laser, and the random laser reflection module is used to reduce the lasing threshold of the random laser. The output end of the pump source and the output end of the random laser reflection module are both connected to the input end of the beam combiner. The output end of the beam combiner, the gain fiber, the first long-distance single-mode communication fiber, and the total output end are connected in sequence. Among them, the pump light of the pump source is input into the gain fiber through the beam combiner. The gain fiber generates signal light under the action of the pump light. The signal light is incident on the random laser reflection module through the beam combiner. The signal light reflected by the random laser reflection module and the pump light of the pump source are coupled into the gain fiber through the beam combiner. After being provided with gain by the gain fiber, it is input into the first long-distance single-mode communication fiber. After supercontinuum spectral fiber laser is generated by the nonlinear effect in the first long-distance single-mode communication fiber, it is output through the total output end.

[0005] Preferably, the random laser reflection module includes an optical fiber coupler. The optical fiber coupler includes a first port, a second port, a third port, and a fourth port. The first port and the second port are located on the side of the optical fiber coupler away from the beam combiner, and the third port and the fourth port are located on the side of the optical fiber coupler close to the beam combiner. The first port and the second port are fusion spliced, and the third port is connected to the input end of the beam combiner.

[0006] Further, the random laser reflection module further includes a second long-distance single-mode communication optical fiber, which is used to generate supercontinuum fiber laser. The third end, the second long-distance single-mode communication optical fiber, and the input end of the beam combiner are connected in sequence.

[0007] Still further, both the first long-distance single-mode communication optical fiber and the second long-distance single-mode communication optical fiber are SMF28 optical fibers; the lengths of the first long-distance single-mode communication optical fiber and the second long-distance single-mode communication optical fiber are both ≥ 100 m; the gain optical fiber is a single-mode optical fiber.

[0008] Further, the optical fiber coupler is a 2*2 single-mode optical fiber coupler. The first port and the second port are the input ends of the optical fiber coupler, and the third port and the fourth port are the output ends of the optical fiber coupler.

[0009] Preferably, the pump source is a semiconductor laser.

[0010] Preferably, the wavelength of the pump light output by the pump source is 976 nm.

[0011] Preferably, the gain optical fiber is a ytterbium-doped optical fiber.

[0012] Compared with the prior art, a supercontinuum spectrum based on random laser in the present invention generates supercontinuum based on fiber random laser technology, has a simple and reliable structure, a wider working wavelength range, stronger multiplexing ability, and can effectively avoid the loss of the supercontinuum light source during fiber transmission; uses the first long-distance single-mode communication optical fiber, has good compatibility and excellent beam quality; reduces the lasing threshold of the random laser through the random laser reflection module, reduces the supercontinuum threshold, and enhances the practicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0014] Figure 1 It is a schematic structural diagram of a supercontinuum light source based on random laser according to an embodiment of the present invention.

[0015] Figure 2 It is a schematic structural diagram of a supercontinuum light source based on random laser according to another embodiment of the present invention.

[0016] Figure 3 It is a schematic structural diagram of a supercontinuum light source based on random laser according to still another embodiment of the present invention.

[0017] Figure 4 Spectral output result diagram of a supercontinuum light source based on random laser according to an embodiment of the present invention. Embodiment

[0018] To further understand the purpose, structure, features, and functions of the present invention, the following is a detailed description in conjunction with embodiments.

[0019] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0020] Please refer to Figure 1 , a supercontinuum light source based on random laser of the present invention includes a pump source 1, a beam combiner 2, a gain fiber 3, a first long-distance single-mode communication fiber 4, a total output end 5, and a random laser reflection module 6.

[0021] The pump source 1 is used to output pump light. The beam combiner 2 is used to couple the pump light of the pump source 1 and the signal light generated by the gain fiber 3 reflected by the random laser reflection module 6 into the gain fiber 3. The gain fiber 3 is used to provide gain for the random laser. The first long-distance single-mode communication fiber 4 is used to generate supercontinuum fiber laser. The random laser reflection module 6 is used to reduce the lasing threshold of the random laser.

[0022] The output end of the pump source 1 and the output end of the random laser reflection module 6 are both connected to the input end of the beam combiner 2. The output end of the beam combiner 2, the gain fiber 3, the first long-distance single-mode communication fiber 4, and the total output end 5 are connected in sequence.

[0023] The pump light of the pump source 1 is input into the gain fiber 3 through the beam combiner 2. The gain fiber 3 generates signal light under the action of the pump light. The signal light is incident on the random laser reflection module 6 through the beam combiner 2. The signal light reflected by the random laser reflection module 6 and the pump light of the pump source 1 are coupled into the gain fiber 3 through the beam combiner 2. After being provided with gain by the gain fiber 3, it is input into the first long-distance single-mode communication fiber 4. After generating supercontinuum fiber laser by the nonlinear effect in the first long-distance single-mode communication fiber 4, it is output through the total output end 5.

[0024] The supercontinuum light source generates a supercontinuum spectrum based on fiber random laser technology, with a simple and reliable structure, a wider working wavelength range, stronger multiplexing ability, and can effectively avoid the loss of the supercontinuum spectrum light source during fiber transmission; the first long-distance single-mode communication fiber 4 is used, with good compatibility and excellent beam quality; the random laser reflection module 6 reduces the lasing threshold of the random laser, the supercontinuum threshold is reduced, and the practicability is enhanced.

[0025] In actual use, the pump source 1 generally selects a semiconductor laser with fiber output; the wavelength of the pump light output by the pump source 1 is 976nm, 915nm, etc. Considering the absorption efficiency, the wavelength of the pump light output by the pump source 1 is preferably 976nm; the gain fiber 3 is preferably a ytterbium-doped fiber.

[0026] Please refer to Figure 2 , Figure 2 FIG. is a schematic structural diagram of a supercontinuum light source based on random laser according to another embodiment of the present invention. Compared with the embodiment in Figure 1 In this embodiment, the random laser reflection module 6 includes a fiber coupler 61. The fiber coupler 61 includes a first port 611, a second port 612, a third port 613, and a fourth port 614. The first port 611 and the second port 612 are located on the side of the fiber coupler 61 away from the beam combiner 2, and the third port 613 and the fourth port 614 are located on the side of the fiber coupler 61 close to the beam combiner 2. The first port 611 and the second port 612 are fused, and the third port 613 is connected to the input end of the beam combiner 2.

[0027] By fusing the first port 611 and the second port 612, the fiber coupler 61 can be used as a broadband reflector to provide feedback for the system and reduce the random laser threshold.

[0028] In actual use, the fiber coupler 61 can be a 2*2 single-mode fiber coupler. The first port 611 and the second port 612 are the input ends of the fiber coupler 61, and the third port 613 and the fourth port 614 are the output ends of the fiber coupler 61; when the first port 611 and the second port 612 are fused and used as a broadband reflector, the third port 613 is the input end and the output end of the broadband reflector. The third port 613 is used to receive the signal light from the gain fiber 3 and output the signal light after reflection.

[0029] Please refer to Figure 3 , Figure 3 FIG. is a schematic structural diagram of a supercontinuum light source based on random laser according to still another embodiment of the present invention. Compared with Figure 2Compared with the embodiments in [reference], the random laser reflection module 6 further includes a second long-haul single-mode communication optical fiber 62, which is used to generate supercontinuum fiber laser. The third end 613, the second long-haul single-mode communication optical fiber 62, and the input end of the beam combiner 2 are connected in sequence.

[0030] The pump light of the pump source 1 is input into the gain fiber 3 to make the gain fiber 3 generate signal light. The signal light is sequentially input into the second long-haul single-mode communication optical fiber 62 and the third port 613 of the fiber coupler 61 through the beam combiner 2. Under the reflection of the third port 613 and the random feedback of the second long-haul single-mode communication optical fiber 62, laser radiation is formed.

[0031] To reduce costs, both the first long-haul single-mode communication optical fiber 4 and the second long-haul single-mode communication optical fiber 62 are SMF28 optical fibers. On the one hand, this fiber can provide Rayleigh scattering to provide feedback for random lasers. On the other hand, it can also provide nonlinear effects to generate Raman frequency shift and broadening processes.

[0032] To ensure the spectral width of the supercontinuum light source, the lengths of both the first long-haul single-mode communication optical fiber 4 and the second long-haul single-mode communication optical fiber 62 are ≥100 m.

[0033] Preferably, the gain fiber 3 is a single-mode fiber. Adopting an all-single-mode fiber structure, it has good compatibility and excellent beam quality.

[0034] Taking Figure 3 the structure in [reference] as a reference, the present invention can be specifically the following embodiments:

[0035] The pump source 1 is a semiconductor pump laser with fiber output, with a power of 9 W and a wavelength of 976 nm; the beam combiner 2 is a (2 + 1)*1 pump coupler; the gain fiber 3 is a 4-m-long non-polarization-maintaining ytterbium-doped fiber, and the fiber model is LMA-YDF-10 / 130-M; both the first long-haul single-mode communication optical fiber 4 and the second long-haul single-mode communication optical fiber 62 are 150-m-long SMF28 optical fibers to provide random distributed feedback and nonlinear gain based on Rayleigh scattering; the fiber coupler 61 is a 1064 nm 1:1 non-polarization-maintaining coupler. One end of the fiber coupler 61 is fused and used as a broadband reflector to provide feedback for the system and reduce the random laser threshold.

[0036] The working principle of this embodiment is as follows: The 976nm pump source 1 provides excitation. After passing through the beam combiner 2, the pump laser is input into the gain fiber 3. Under the pumping of the pump laser, ytterbium ions in the gain fiber 3 transition to the upper energy level to form a population inversion state. The particles in the upper energy level will spontaneously transition to the lower energy level and radiate photons. The radiated photons, under the mirror feedback provided by the fiber coupler 61 and the random feedback provided by Rayleigh scattering in the second long-distance single-mode communication fiber 62, excite more photons to form laser radiation. The wavelength band of this laser radiation covers 1000 - 1100nm. With higher pump power, 1060nm near the gain peak will have a competitive advantage. Due to the instability of mode competition and random feedback, the generation of random laser will show pulsed light output in the time domain, which results in the laser having a very high peak power. The laser with a high peak power excites stimulated Raman scattering in the second long-distance single-mode communication fiber 62 and the first long-distance single-mode communication fiber 4, and the wavelength rapidly expands from 1 micron to above 1.3 microns. When the wavelength of the output laser reaches the zero-dispersion point of the fiber, supercontinuum output appears.

[0037] Connect the total output terminal 5 to the spectrometer, and the output result is as Figure 4 shown. In the figure, the horizontal axis is the wavelength, the vertical axis is the power, the power output is 50MW. Limited by the test range of the spectrometer, the spectral range is only measured to cover 600 - 2000nm. The working wavelength range is wide, fully meeting the application requirements.

[0038] A supercontinuum light source based on random laser of the present invention generates a supercontinuum spectrum based on fiber random laser technology, has a simple and reliable structure, a wider working wavelength range, stronger multiplexing ability, and can effectively avoid the loss of the supercontinuum spectrum light source during fiber transmission; uses the first long-distance single-mode communication fiber, has good compatibility and excellent beam quality; reduces the lasing threshold of the random laser through the random laser reflection module, reduces the supercontinuum threshold, and enhances the practicability.

[0039] The present invention has been described by the above related embodiments. However, the above embodiments are only examples for implementing the present invention. In addition, the technical features involved in different embodiments of the present invention described above can be combined with each other as long as they do not conflict with each other. It must be pointed out that the disclosed embodiments do not limit the scope of the present invention. On the contrary, modifications and refinements made without departing from the spirit and scope of the present invention fall within the patent protection scope of the present invention.

Claims

1. A supercontinuum light source based on random lasing, characterized in that It includes a pump source, a beam combiner, a gain fiber, a first long-distance single-mode communication fiber, a total output end, and a random laser reflection module. The first long-distance single-mode communication fiber is used to generate supercontinuum fiber laser, and the random laser reflection module is used to reduce the lasing threshold of the random laser. The output end of the pump source and the output end of the random laser reflection module are both connected to the input end of the beam combiner. The output end of the beam combiner, the gain fiber, the first long-distance single-mode communication fiber, and the total output end are connected in sequence. The random laser reflection module includes an optical fiber coupler and a second long-distance single-mode communication fiber. The second long-distance single-mode communication fiber is used to generate supercontinuum fiber laser. The optical fiber coupler includes a first port, a second port, a third port, and a fourth port. The first port and the second port are located on the side of the optical fiber coupler away from the beam combiner, and the third port and the fourth port are located on the side of the optical fiber coupler close to the beam combiner. The first port and the second port are fusion spliced, and the third port, the second long-distance single-mode communication fiber, and the input end of the beam combiner are connected; Among them, the pump light of the pump source is input into the gain fiber through the beam combiner. The gain fiber generates signal light under the action of the pump light. The signal light is incident on the second long-distance single-mode communication fiber of the random laser reflection module and the third port of the optical fiber coupler through the beam combiner in sequence, and forms laser radiation under the reflection of the third port and the random feedback of the second long-distance single-mode communication fiber. The signal light reflected by the random laser reflection module and the pump light of the pump source are coupled into the gain fiber through the beam combiner, and after being provided with gain by the gain fiber, they are input into the first long-distance single-mode communication fiber. After supercontinuum fiber laser is generated by non-linear effect in the first long-distance single-mode communication fiber, it is output through the total output end.

2. The supercontinuum light source based on random laser as described in claim 1, characterized in that, The optical fiber coupler is a 2*2 single-mode optical fiber coupler. The first port and the second port are the input ends of the optical fiber coupler, and the third port and the fourth port are the output ends of the optical fiber coupler.

3. The supercontinuum light source based on random laser according to claim 1, characterized in that, Both the first long-distance single-mode communication fiber and the second long-distance single-mode communication fiber are SMF28 fibers.

4. The supercontinuum light source based on random laser according to claim 1, wherein The lengths of both the first long-distance single-mode communication fiber and the second long-distance single-mode communication fiber are ≥100m.

5. The supercontinuum light source based on random laser as claimed in claim 1, wherein The gain fiber is a single-mode fiber.

6. The supercontinuum light source based on random laser as described in claim 1, wherein The pump source is a semiconductor laser.

7. The supercontinuum light source based on random laser as claimed in claim 1, wherein The wavelength of the pump light output by the pump source is 976nm.

8. The supercontinuum light source based on random laser according to claim 1, characterized in that The gain fiber is a ytterbium-doped fiber.

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