A wide tunable fiber laser for two independent C-band and l-band wavelengths

A double-ring laser with a single 1480 nm pump was proposed and demonstrated using the combination of a ring coupler and a C/L-band coupler. One ring for an L-band wavelength was pumped by a lasing light which was transferred from the other ring for a C-band wavelength. The laser had a total bandwidth of 70 nm, with 35 nm continuously tunable at each wavelength band within a 1 dB power deviation. High lasing powers of more than 0 dBm were maintained as the pump power decreased to 60 mW. This laser also supported two independent tunable lasing wavelengths at the same time. The 1557 nm pumped L-band lasing had 25% improvement in power conversion efficiency and 60% reduction in threshold pump power compared with directly 1480-nm-pumped L-band lasing. This wide bandwidth and highly power-equalized laser was achieved with high output lasing power and low power consumption.