Frequency-modulated, tunable, semiconductor-optical-amplifier-based fiber ring laser for linewidth and line shape control.
We report how the linewidth and line shape of a tunable semiconductor-optical-amplifier-based fiber ring laser can be actively adjusted by applying an intracavity frequency modulation to the laser. Frequency-modulated laser operation is achieved by driving the phase modulator frequency close to the cavity axial-mode spacing, leading to a constant-amplitude laser output having a periodically varying instantaneous frequency. The resulting linewidth varies proportionally with the inverse of the frequency detuning, and it is adjustable from submegahertz to over more than 5 GHz. By appropriate selection of the modulating waveform we have synthesized a near-Gaussian output line shape; other line shapes can be produced by modifying the modulating waveform. Experimental observations are in good agreement with a simple model.
Girard
Simon Lambert
SL
Centre d'Optique, Photonique et Laser, University Laval, Quebec, Canada. simon.lambart-girard.1@ulaval.ca
Chen
Hongxin
H
Schinn
Gregory W
GW
Piché
Michel
M
D000669:Amplifiers, Electronic; D004867:Equipment Design; D007834:Lasers; D054023:Lasers, Semiconductor; D008027:Light; D015233:Models, Statistical; D016011:Normal Distribution; D055095:Optics and Photonics; D012666:Semiconductors