Optical-pulse-injection-iniduced 40 GHz photonic frequency multiplication in erbium-doped fiber laser

Abstract

The generation of a 40 GHz regeneratively amplified and frequency-multiplied optical pulse train from an erbium-doped fiber ring laser is demonstrated. This is achieved by seeding a I GHz gain-switched Fabry-Perot laser diode and detuning its repetition frequency to coincide with the harmonic resonant cavity mode. The peak power of frequency-multiplied erbium-doped fiber lasers (EDFL) pulses increases from 80 mW to 230 mW as the modulation level of the Fabry-Perot laser diode (FPLD) increases from 18 dBm to 30 dBm. The pulsewidth and peak power are 10 ps and 5 mW at a repetition rate of 40 GHz. The EDFL longitudinal mode frequency fluctuation is within +/-2.5 kHz during 2 h. The frequency-multiplied EDFL pulses exhibit relatively low phase noises of -95 dBc/Hz and -120 dBc/Hz at offset frequencies of 10 kHz and I MHz, respectively. The associated timing jitter of the EDFL pulses exponentially increases from 0.6 ps to beyond 5.8 ps as the frequency multiplication order increases from I to 40.