A photonic generation of multi-frequency source based on the heterodyne of two phase-locked optical frequency combs（OFCs） is proposed and demonstrated.By applying an optical phase-locked loop,the phase noise induced by optical links is decreased by approximately 70,66,and 35 dB at 0.01,0.1,and 1.0 Hz offset frequencies,respectively.The proposed scheme provides 8 radio frequency signals,the frequencies of which span from 540 to 4040 MHz,with a 500-MHz interval.The number of generated signals can be readily scaled by using OFCs with broader bands,whereas the frequencies can be scaled by tuning the repetition rates of OFCs.
线性扫频激光源在高分辨率、高精度、大动态范围的激光测量和光纤传感领域有着广泛的应用。然而,扫频非线性及激光相位噪声限制了测量系统的分辨率、精度和动态范围。分析了分布反馈式(DFB)半导体激光扫频中的非线性及激光相位噪声产生的机制,提出基于预畸变和光锁相的激光扫频非线性校正和激光相位噪声抑制方法,实现了扫频范围为50 GHz,均方根频率误差小于263 k Hz的激光扫频信号。实验测试表明该扫频激光源的线性度和相干性得到了有效增强。
This letter presents a low cost solution for wavelength division multiplexed orthogonal frequency division multiplexed passive optical network （WDM-OFDM-PON） with widely tunable optical filter and linear small form-factor pluggable （SFP） module. With 9-nm tunable range from 1551 to 1560 nm, the tunable filter can support up to 10-channel 100-GHz spacing WDM PON system. A linear avalanche photodiode （APD） based SFP＋ module is designed for optical OFDM signal demodulation, which can provide better receiver performance compared with limiting APD module. Experimental results show that -34 dB power budget can be achieved in 4x5-Gbps WDM-OFDM-PON system, which can satisfy the transmission requirements of next generation PON system.
