Low-noise polarization-maintaining single-frequency fiber laser

Abstract

Provided in the invention is a low-noise polarization-maintaining single-frequency fiber laser comprising a multi-component glass optical fiber, a broadband fiber grating, a narrow-band polarization-maintaining fiber grating, a PZT piezoelectric ceramics, a polarization-maintaining wavelength division multiplexer, a polarization-maintaining optoisolator, a pumping source and a heat sink. The PZT piezoelectric ceramics is fixed at the side of the multi-component glass optical fiber or the side of one end of a silica fiber of the broadband fiber grating; and the direct-current bias voltage loaded by the piezoelectric ceramics is changed and different lateral stresses are exerted on the fiber, so that the polarization state can be controlled in real time. When a stable linear polarization state occurs, a slow axis entering the narrow-band polarization-maintaining fiber grating is transmitted; and after reflection, frequency selection is carried out. Therefore, the random change, caused by the disturbance of the external environment, of the polarization state can be prevented; the conversion efficiency is improved; and the noises are reduced. According to the invention, the polarization-maintaining single-frequency fiber laser output whose signal to noise ratio is larger than 65dB, the extinction ratio is larger than 28dB, the relative intensity noise value is less than -130dB / Hz, and the output power is larger than 100mW can be obtained.

Description

technical field [0001] The invention relates to a laser light source, in particular to a low-noise, polarization-maintaining output single-frequency fiber laser. [0002] Background technique [0003] Single-frequency (single longitudinal mode) fiber laser refers to working in a single longitudinal mode operation state, with the advantages of narrow output spectral linewidth, adjustable frequency, long coherent length, low noise, compact structure, etc. Lidar, nonlinear frequency conversion, and high-precision spectral measurement are widely used in fields such as laser radar, but some application fields especially require low-noise, polarization-maintaining output characteristics of single-frequency lasers. [0004] There are many ways to obtain linearly polarized single-frequency laser output. Generally, a ring cavity or a compound cavity structure is used (the resonator cavity is long, suitable for inserting polarization-related components in the cavity), and a polarizat...

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Problems solved by technology

There are some problems in the design of the above-mentioned cavity structure: the cavity length of the resonant cavity is too long, the longitudinal mode spacing is too dense, and it is easy to be affected by external environmental disturbances (such as temperature changes, vibrations) and cause mode hopping and multi-longitudinal mode phenomena, single-frequency work stability Poor, and can only output lasers of tens of mW at most

The output lasers in the above papers do not have low noise or polarization-maintaining characteristics. The reasons are: on the one hand, it is relatively difficult to design and manufacture the polarization-maintaining type multi-component glass optical fiber, and the implementation cost of the full polarization-maintaining optical path is high and the structure Complex; on the other hand, the linear short and straight resonant cavity is limited by the cavity length design, and it is difficult to insert other polarization-maintaining components (such as polarization controllers, polarizers) in the cavity

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