WAVELENGTH TUNABLE PASSIVELY Q-SWITCHED FIBER RING LASER USING GALLIUM ARSENIDE BASED MICROCHIP SATURABLE ABSORBER

Abstract

The work presented in this study is focused on developing a widely wavelength tunable Q-switched pulsed erbium doped fiber ring laser (EDFRL) source operating in microsecond regime in Telecom wavelength spectrum of 1.55 μm ( C and L bands ). A commercial Gallium arsenide (GaAs) based microchip saturable absorber (SA) is used in the proposed EDFRL configuration to passively initiate Q-switching for stable pulse generation. Unless low damage threshold of the commercial GaAs based SA and non-optimized cavity length and losses, sufficiently stable pulse trains were obtained for a wide wavelength tuning range of 50 nm from 1520 nm to 1570 nm with high repeatability and long-term stability. The Q-switched output pulses of the proposed EDFRL have output average powers varying from +0.65 dBm to +1.53 dBm, the pulse widths varying from 4.27 μs to 7.16 μs and the repetition rates varying from 51.51 kHz to 31.42 kHz for different tuning wavelengths.