A switchable and wavelength-spacing tunable single-frequency and single-polarization dual-wavelength erbium-doped fiber laser based on a compound-cavity structure

摘要

A switchable and wavelength-spacing tunable single-frequency and single-polarization dual-wavelength erbium-doped fiber laser is proposed and demonstrated experimentally. The fiber laser is composed of a main linear cavity and two subring cavities. In dual-wavelength operation, the wavelength spacing can be tuned from 0.430 nm to 4.487 nm, showing that the fiber laser can be used for photonic generation of a microwave signal with a tunable frequency range from 54 GHz to 563 GHz; in single-wavelength operation, the fiber laser can either work at a fixed wavelength of 1544.108 nm or work at a wavelength with a tunable range of 4.057 nm, from 1544.538 nm to 1548.595 nm. The linewidths of two wavelengths are approximately 760 Hz and 810 Hz respectively. The polarization-extinction ratios of the laser outputs, both in dual-and single-wavelength operation, are higher than 30 dB. Key words: fiber laser, single-frequency, single-polarization, dual-wavelength, wavelength-spacing-tunable, switchable.