OPTICAL FIBER AMPLIFIER AND 1.48 MU-M HIGH-POWER PUMPING LASER MODULE

An Er-doped optical fiber amplifier is a very attractive device for extending the transmission span and for compensating optical losses at the branching network. In the Er-doped optical fiber amplifier, a high power laser diode module is quite an important device for pumping an Er ion. The authors have developed 1.48-mu-m high power laser diode modules with over 100 mW output power and get a perspective for practical use of it. This module has a newly developed Multiple Quantum Well (MQW) Fabry-Perot laser and an aspherical lens. The lens has a very low wavefront aberration to reduce a laser-to-fiber coupling loss to only 2 dB. A pigtail is a polarization maintaining fiber and makes it possible to realize either redundancy system for improving reliability or a laser duplication system for increasing the pumping power.