Beat-spectrum-tailoring of fiber lasers with an intracavity Fabry-Perot filter for high repetition-rate regenerative mode-locking

Summary form only given. The regenerative method of mode locking has been proved to be a very effective way for the generation of extremely stable high repetition pulses from fiber lasers which is the key to future optical communication systems. This is accomplished by extracting a higher harmonic of the cavity beat-note using a high-Q RF filter (Q=100-1500) and feed-backing of the extracted clock signal in a regenerative manner. However, as one desires to increase the operating frequency above several tens of GHz, the use of such RF filters becomes inconvenient because of the difficulty in their fabrication and excessively high insertion loss. A novel scheme which shows an alternative means of regenerative mode locking by avoiding this type of high-Q RF filter and suites for operation at tens of GHz repetition rate is demonstrated. This is based on the tailoring of the beat spectrum of the laser using an intracavity fiber Fabry-Perot (FP) filter, which is available commercially with a free spectral range (FSR) of tens to hundreds of GHz.