Stability study of full polarization maintaining electro-optical frequency comb system based on chirped fiber Bragg grating

As a bridge between optical and microwaves, optical frequency combs play an important role in optical communication, optical signal processing, and microwave photonics. The electro-optical frequency comb has the advantages of reconfigurability and spectral flatness, and is a major optical frequency comb generation scheme, while dispersion compensation is an important part in generating electro-optical frequency comb pulses. Single mode fiber (SMF) is widely used in electro-optical comb systems due to its low cost and high flexibility, but its non-polarization- preserving characteristics will result in significant polarization sensitivity, resulting in limited ability of the system to resist vibration and other interference. In addition, the dispersion of SMF is small, and in order to effectively compress the width of electro-optical frequency pulses, thousands of meters of single-mode fibers are usually required. In contrast, chirped fiber Bragg grating (CFBG) has the characteristics of polarization-preserving and small size, and is an excellent dispersion compensation element. However, there are still few studies on the stability of high-dispersion CFBG in electro-optical frequency comb. In this study, the effects of SMF and CFBG on the optical power and waveform stability of the electro-optical comb system were compared. The experimental results show that, firstly, the standard deviation of the optical power fluctuation of the electro-optical frequency comb system using SMF as the dispersive element is 0.013% in half an hour, and 0.11% for using CFBG, Secondly, the waveform stability of the optical frequency comb system with SMF as the dispersive element is 1.09%, compared to 1.03% for the system using the CFBG without additional polarization control. The experimental results provide support for the practical application of CFBG in compact electro-optical frequency combs.