GHz-repetition-rate fiber laser with a multi-wavelength profile based on a hybrid fiber cavity

An optical communication system based on the pulsed laser with a GHz repetition rate and multi-wavelength operation enables an increase in data transmission rate and data capacity.We propose a novel hybrid cavity with a single-mode fiber/multi-mode fiber/single-mode fiber (SMF-MMF-SMF) configuration for a GHz ultrafast laser with multi-wavelength operation.The length of each section is elaborately designed to reduce the transmission loss between the SMF and MMF, as well as to limit its total length to under 10 cm.By adopting the proposed hybrid cavity, the >1 GHz-repetition-rate fiber laser operation with four wavelength peaks is demonstrated, showing a signal-to-noise ratio of 90 dB.Furthermore, great tunability in spectra by manipulating the launched cavity parameters is also proved.To the best of our knowledge, this is the first realization of multi-wavelength operation among the GHz lasers using the SMF-MMF-SMF cavity architecture.The finding might provide a new opportunity for large-capacity high-speed optical communication systems.