Zhou Kaijun, Zhao Qilai, Huang Xiang, Yang Changsheng, Li Can, Zhou Enbo, Xu Xiaogeng, Wong Kenneth K Y, Cheng Huihui, Gan Jiulin, Feng Zhouming, Peng Mingying, Yang Zhongmin, Xu Shanhui
Opt Express. 2017 Aug 21;25(17):19752-19759. doi: 10.1364/OE.25.019752.
A kHz-order linewidth controllable 1550 nm single-frequency fiber laser (SFFL) is demonstrated for the first time to our best knowledge. The control of the linewidth is realized by using a low-pass filtered white Gaussian noise (WGN) signal applied on a fiber stretcher in an optical feedback loop. Utilizing WGN signals with different signal amplitudes An and different cutoff frequencies fc, the linewidths are availably controlled in a wide range from 0.8 to 353 kHz. The obtained optical signal-to-noise ratio (OSNR) is more than 72.0 dB, and the relative intensity noise (RIN) at frequency greater than 40 MHz reaches -148.5 dB/Hz which approaches the shot noise limit (-152.9 dB/Hz). This kHz-order linewidth controllable SFFL is meaningful and valuable, for optimizing the receiver sensitivity and bit error rate (BER) performance of the coherent optical communication system based on high-order quadrature amplitude modulation (QAM).
据我们所知，首次展示了一种线宽可控的千赫兹级1550纳米单频光纤激光器（SFFL）。通过在光反馈回路中的光纤拉伸器上施加低通滤波的白高斯噪声（WGN）信号来实现对线宽的控制。利用具有不同信号幅度An和不同截止频率fc的WGN信号，线宽可在0.8至353千赫兹的宽范围内有效控制。获得的光信噪比（OSNR）大于72.0分贝，频率大于40兆赫兹时的相对强度噪声（RIN）达到-148.5分贝/赫兹，接近散粒噪声极限（-152.9分贝/赫兹）。这种千赫兹级线宽可控的SFFL对于优化基于高阶正交幅度调制（QAM）的相干光通信系统的接收机灵敏度和误码率（BER）性能具有重要意义和价值。
