Ultrashort pulse generation from continuous wave by pulse trapping in birefringent fibers

We investigated the phenomenon of orthogonally polarized pulse trapping between a continuous-wave beam and an ultrashort soliton pulse in birefringent fibers both experimentally and numerically. Using pulse trapping and amplification, we demonstrated ultrashort pulse generation from a continuous-wave beam. The generated pulse had a nearly transform-limited sech(2)-shape and a temporal width of 350 fs. The obtained maximum pulse energy was 300 pJ using a 400 m-long low-birefringence fiber, and the corresponding gain was as large as 41 dB.