In this Letter, a novel multiple self-mixing interferometer for a fiber ring laser (FRL) is designed by introducing a circular feedback cavity. A system model is established based on an injection-seeded erbium-doped FRL proposed by Dragic. Owing to the reflection of the collimating lens, the multiplied fringes have different depths, which shows two Doppler frequencies in the spectrum of the self-mixing signal. A double-peak frequency identification algorithm is proposed to extract the Doppler frequency from the unique signal. This technique has the potential to improve the accuracy of fiber self-mixing measurement systems, particularly in Doppler velocimeters.

中文翻译：

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光纤环形激光器的多重自混合干涉仪的设计

在这封信中，通过引入圆形反馈腔设计了一种新颖的用于光纤环形激光器（FRL）的多重自混合干涉仪。基于Dragic提出的注入种子的掺-FRL建立了系统模型。由于准直透镜的反射，相乘的条纹具有不同的深度，这在自混合信号的频谱中显示了两个多普勒频率。提出了一种双峰频率识别算法，用于从唯一信号中提取多普勒频率。该技术具有提高纤维自混合测量系统准确性的潜力，尤其是在多普勒测速仪中。