Contents 1. Introduction
Ultra-wide band optical amplifiers and optical sources are essential to utilize the intrinsic ultra-wideband transmission window (over 200 nm) of optical fibers even in the 1.5-μm range. Several types of wide-band optical fiber amplifiers have been reported, including two gain band EDFAs [1], and EDFA/Raman hybrid amplifiers with more than 80-nm bandwidth [2]. Recently, it was reported that the tellurite fiber Raman amplifier had an extremely large gain-bandwidth of 160 nm [3], and that the hybrid tellurite/silica fiber Raman amplifier (HRA) achieved an improved gain-flatness [4]. A supercontinuum lightwave source is a promising way for generating over 100-channel optical carriers for WDM photonic networks, because it can provide high SNR and wideband spectra [5] So far, DWDM transmission was demonstrated using 25-GHz-spaced, 106-channel optical carriers generated from a single SC source [6].
