Patent ID: 7653316

Claim:
A discretely ITU-T channel grid wavelength tunable single longitudinal mode erbium-doped fiber ring laser, fabricated to discretely tune a channel wavelength satisfying ITU-T grid channel value of 193.1 THz ±n*12.5 GHz (n is an integer) specified by ITU-T Recommendation G.692 and G694.1 in a C-band and an L-band in a discrete wavelength tunable single longitudinal mode ring type optical fiber structure, comprising: first and second erbium-doped optical fibers that are saturable absorbers having first and second optical fiber amplification stages having a unidirectional structure, an air gap etalon filter having an air gap, a fiber wavelength tunable etalon filter, and a saturable absorber composed of an erbium-doped optical fiber are serially connected with one another such that they can be simultaneously used.