講演情報
[19p-B205-4]Tunable-Repetition-Rate Dual-Comb Generation in a Polarization-Maintaining Bidirectional Fiber Laser
〇(DC)BOWEN LIU1, MAOLIN DAI1, YIFAN MA1, TAKUMA SHIRAHATA1, SHINJI YAMASHITA1, SZE YUN SET1 (1.The Univ. of Tokyo)
キーワード：
Bidirectional mode locking、Tunable repetition rate、Polarization-maintaining fiber laser
Ultrafast laser is an ideal playground for the study of precise spectroscopy and microscopy that heavily rely on the high-performance optical frequency combs, which is the unique nature of mode-locked fiber laser. In particular, dual-comb fiber laser can greatly improve system performance while reducing complexity by developing self-referencing combs and coupling pulse trains with different repetition rates. Whereas the repetition rate is generally determined for a certain lasing resonator, which creates additional constraints in dual-comb applications. In this paper, we demonstrate a bidirectional polarization-maintaining mode-locked fiber laser, of which the two orthogonal polarization components propagating along fast- and slow-axis are bidirectionally multiplexed resonate clockwise and counterclockwise, respectively. The repetition rate of clockwise lasing pulses is fixed according to the certain cavity length, while the one of another lasing components traveling opposite can be tuned continuously through the intra-cavity delay line. The maximum tuning range of the counterclockwise repetition rate reaches 681.6 kHz. Compared with fixed loop, the largest RF difference between two combs is 978.2 kHz, almost equals to 1 MHz. Meanwhile, the dual combs generate in two opposite directions have nearly the same central wavelength, enabling high coherence. Different from most current dual-comb solutions, this high-coherent characteristic could greatly improve the performance of the dual-comb system, making it also have potential in some specific spectroscopy and microscopy measurement scenarios.