Fiber device for fusing fiber distributed feedback (DFB) laser and fiber amplifier

Abstract

The invention relates to a fiber device for fusing a fiber distribution feedback laser and a fiber amplifier, belonging to the technical field of fiber layers. The device comprises a pump light source of 980nm, a wavelength division multiplexer, a DFB-FL (Fiber Laser) and an isolator. The device is characterized in that the lengths of reserved erbium-doped fibers when the erbium-doped fibers are arranged at the front end of the DFB-FL and the lengths of the reserved erbium-doped fibers when the erbium-doped fibers are arranged at the rear end of the DFB-FL are increased to 15-120 cm. The invention integrates the generation and the amplification of laser together, has simple structure, and not only reasonably utilizes the pump light, but also reduces the loss caused by fiber splicing. Moreover, the invention is convenient for the multiplexing of a plurality of devices and convenient for forming a sensing network, and the sensing of each stage has own amplification, which guarantees the signal intensity in a sensing process and facilitates demodulating signals in subsequent systems, thus the device can be widely applied to fiber communication and fiber sensing.

Description

technical field [0001] The invention relates to an optical fiber device integrating a fiber distributed feedback laser (DFB-FL) and a fiber amplifier, specifically a novel fiber device integrating a fiber distributed feedback laser and a fiber amplifier, and belongs to the technical field of fiber lasers. Background technique [0002] At present, lasers are used more and more widely. Distributed feedback fiber laser (DFB-FL) has the advantages of extremely narrow linewidth, high signal-to-noise ratio, linearly adjustable wavelength, low phase noise and stable single-mode output. , can be used as an extremely superior light source for optical fiber sensing systems for ultra-long-distance, ultra-high-precision and ultra-high-sensitivity sensing. [0003] The DFB (Distributed Feed Back) fiber laser is different from the traditional laser. It does not have a traditional cavity mirror, but a grating written directly in the rare earth doped fiber to form a resonant cavity. The act...

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Problems solved by technology

[0004] Increase the pumping power of the DFB fiber laser. When the pumping power is strong, the output laser intensity will be correspondingly enhanced. This method has a simple structure, but requires a strong pumping light, and puts forward a higher requirement for the pumping source. requirements, coupled with low conversion efficiency, a large part of the pump light is wasted, and when the pump light intensity reaches a certain value, the conversion efficiency will decrease, and most of the pump light passes through the DFB-FL , can not play the role of pumping, such as figure 1 shown

[0005] The outgoing DFB fiber laser enters the fiber amplifier and further amplifies the DFB-FL, so that it is easy to achieve the power we need. The problem is that we need to add another fiber amplifier (EDFA), and add a pump source. It causes an increase in cost, and when using DFB-FL to form a sensor network and multiple DFB-FLs are multiplexed, it is impossible for us to add an EDFA to each DFB-FL. This solution is obviously unfeasible, such as image 3 shown

[0006] Paper "Performance Limitations of High-Power DFB Fiber Lasers" [K.H. Member, IEEE, and A.B.Grudinin, IEEE PHOTONICS TECHNOLOGY LETTERS, VOL.15, NO.2, FEBRUARY 2003.] mentioned the above two methods to improve the output power of DFB-FL, and compared them. Low conversion efficiency causes waste of pump light; the latter is a complex system, not suitable for system multiplexing and composition of sensor networks

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