Progress on development of optical frequency combs at NTSC

摘要

In this paper, we demonstrate two techniques to improve performance of Er:fiber frequency combs at NTSC. the first technique is to obtain a robustness and low noise laser, we combine the nonlinear polarization rotation (NPR) and the nonlinear amplifying loop mirror (NALM) mechanisms to a single system. the laser has a large mode-locking range and can self-starting. It works normally after being unpowered six months, and the noise level is similar to the pure NPR. The second technique is proposed a broad bandwidth and large range frequency control method by tuning the polarization state. A special-designed electro-optic modulator (EOM) is used to rotate the polarization state in the NPR system. Compared with the traditional EOM, the sensitivity of f_rto the electric field intensity applied to the EOM is about 100 times larger.