STEP-TUNABLE ALL-FIBER LASER APPARATUS AND METHOD FOR DENSE WAVELENGTH DIVISION MULTIPLEXED APPLICATIONS

摘要

A fiber-optic laser source (10) capable of emitting one useful wavelength at a given time, electrically step-tunable (30) to the grid wavelengths, is disclosed. The laser (10) preferably comprises a diode-pumped rare-earth doped fiber amplifier as gain medium, a periodic filter (20) to define grid laser wavelengths, and a tunable filter (30) step-tunable to any wavelength defined by the periodic filter (20). The arrangement is enclosed in a ring single mode optical fiber resonator. The ring resonator may be made, in part or in total, with polarization-maintaining optical fiber. The resonator also comprises in-line optical isolators (100, 110, 120, 130), to ensure unidirectional operation and to eliminate undesired reflections. A polarization controller (140) and polarizer device and a gain flattening filter (90) may also be included within the resonator depending upon the desired output characteristic of the laser (10). The laser (10) may be designed to operate in single cavity longitudinal mode. The disclosed fiber-optic laser (10) may also comprise output wavelength (160) and/or power (170) definition and stabilization control.