基于SOA的可调谐环形腔光纤激光器

Tunable Ring Cavity Fiber Laser Employing SOA

摘要: 本文设计并研究了一种基于半导体光放大器(SOA)的可调谐环形腔光纤激光器，重点分析其噪声特性及优化方法。通过实验探究输出耦合比、注入电流及腔长对激光输出信噪比的影响，发现SOA的增益饱和效应可有效抑制模式竞争，从而改善噪声性能。实验表明，当输出耦合比为0.1、注入电流为242 mA时，SOA处于深度增益饱和状态，显著提升信噪比至13 dB，并在92 nm调谐范围内实现0.7 dB的功率平坦度和1.79 mW的输出功率。腔长变化对信噪比影响较小，优化后可缩短至10 m以简化结构。研究指出激光器噪声主要源于放大的自发辐射(ASE)，进一步优化滤波器位置有望抑制ASE噪声。此外，采用自由光谱范围更宽的光纤FP滤波器可扩展激光器的可调谐范围。该激光器结构紧凑、性能稳定，为干涉型光纤传感系统的高精度光源设计提供了重要参考。

Abstract: This paper designs and investigates a tunable ring cavity fiber laser based on a Semiconductor Optical Amplifier (SOA), with a focus on analyzing its noise characteristics and optimization methods. Experimental studies demonstrate the effects of output coupling ratio, injection current, and cavity length on the laser’s output signal-to-noise ratio (SNR). It is found that the gain saturation effect of the SOA effectively suppresses mode competition, thereby improving noise performance. Experiments indicate that when the output coupling ratio is 0.1 and the injection current is 242 mA, the SOA operates in deep gain saturation, significantly enhancing the SNR to 13 dB. Additionally, a power flatness of 0.7 dB and an output power of 1.79 mW are achieved across a 92 nm tuning range. Changes in cavity length exhibit minimal impact on SNR, which after optimization can be shortened to 10 m to simplify the structure. The study identifies amplified spontaneous emission (ASE) as the primary source of laser noise, suggesting that optimizing filter placement may effectively suppress ASE noise. Furthermore, employing a fiber Fabry-Pérot (FP) filter with a wider free spectral range (FSR) could extend the laser’s tuning capability. This compact and stable laser provides a significant reference for designing high-precision light sources in interferometric fiber sensing systems.