All-fiber external cavity tunable fiber laser

Abstract

The invention relates to an all-fiber external cavity tunable fiber laser which comprises an external cavity, a wavelength division multiplexer, a tunable fiber grating, gain media and a coupler which are sequentially connected. The external cavity has reflection characteristics, another input port of the wavelength division multiplexer is connected with a pumping unit, pumping laser light emitted by the pumping unit is led into the gain media through the wavelength division multiplexer, so that the particle number of the gain media is reversed, the tunable fiber grating and the coupler form a resonant cavity of the laser, and tunable laser light with the wavelength matched with that of the tunable fiber grating is selected and is outputted by an output port of the coupler. Compared with a semiconductor laser, the fiber laser has the advantages that the laser light is outputted in a single longitudinal mode or less longitudinal mode, the fiber laser can be sufficiently applied to remote sensing measurement by the aid of fine coherent characteristics, mode characteristics and small beam-divergence angles, an all-fiber structure is simple in coupling mode and compact, and the application requirements of special distance measurement places can be met.

Description

technical field [0001] The invention relates to a laser, in particular to an all-fiber external-cavity tunable fiber laser. Background technique [0002] Since the advent of lasers, they have been widely used in optical fiber interference sensing, optical communication networks and other fields. At present, most optical fiber interference sensing systems and optical communication network systems are laser-based interference sensing systems and the laser emitted by the laser is used as the communication signal source, but the line width and tunable characteristics of the laser limit its interference sensing distance, The dynamic characteristics of sensing and the bandwidth of optical fiber communication network and its dynamic characteristics, so the study of narrow linewidth tunable lasers has attracted the attention of many researchers. [0003] Common tunable lasers mainly include external cavity lasers and injection current modulated semiconductor lasers. [0004] Exter...

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Problems solved by technology

[0010] The narrow linewidth tunable laser obtained by the external cavity semiconductor laser mainly has the following problems: 1. The temperature characteristics of the external cavity semiconductor laser affect the output characteristics of the laser, and additional temperature control devices and narrow-band optical filters are required, which increases the Production difficulty and production cost

2. The coupling between external cavity semiconductor laser and optical fiber system is low, which limits its application in optical fiber sensing and optical fiber communication systems

[0012] 1. Since the amplitude of the injection current of the semiconductor laser is limited by the working range of the injection current of the semiconductor, thus limiting the tuning range of its output wavelength, the tuning range of a typical current injection type F-P semiconductor laser is generally around 0.1nm, resulting in a wide range of applications limited;

[0013] 2. When the current injection type semiconductor laser is tuned, the working performance of the laser is unstable, and the output power fluctuates seriously, which affects the application occasion;

[0014] 3. The typical line width range of semiconductor lasers is 2nm, and they generally work in multiple longitudinal modes, resulting in poor monochromaticity and coherence of the laser beam, which affects its transmission and sensing characteristics, and the divergence angle is large when working at a long distance, which directly limits Its application and working distance

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