Discretely tunable single-longitudinal-mode fiber laser stabilized to the channel of the ITU-T grid

Abstract

We propose a fiber ring laser that operates in a single longi- tudinal mode by incorporating unpumped erbium-doped fiber as a satu- rable absorber filter. This laser can be discretely tuned to a 25-GHz- spacing grid that precisely matches ITU-T International Telecommunication Union, Telecommunication Standardization Sector grids, which are reference frequencies for optical communication sys- tems. This laser has a signal-to-source spontaneous emission ratio higher than 60 dB, and the lasing frequencies of 361 channels are matched to ITU-T grids with excellent power flatness. With one channel of this fiber laser, we place the reference frequency near the absolute frequency reference AFR, 193.1 THz. The relative frequency stability of the laser and the frequency offset from the AFR were less than 1.610 8 integrated time, 5 min and 30 MHz, respectively. © 2008 Soci-