Ultrahigh speed picosecond-femtosecond fiber lasers

Stable optical short pulse sources at 1.5 μm are becoming increasingly important in terms of realizing future ultrahigh speed optical communication. We report several new types of erbium-doped fiber laser that we have developed, which are capable of generating picosecond - femtosecond optical pulses. For low repetition rate short pulse generation, a passively mode-locked fiber laser with nonlinear polarization rotation can produce pulses of approximately 100 fs. With regard to high repetition rate pulse generation at 10-20 GHz, a harmonically and regeneratively mode-locked fiber laser can produce picosecond pulses. We also show that femtosecond pulse generation can be achieved at 10-20 GHz by compressing the output pulses of the regeneratively mode-locked fiber laser with a dispersion-decreasing erbium-doped fiber amplifier.