WIDE-WAVELENGTH-RANGE MODULATOR-INTEGRATED DFB LASER-DIODES FABRICATED ON A SINGLE-WAFER

Different-wavelength distributed feedback laser diodes with integrated modulators (DFB/MODs) are fabricated on a single wafer operate at wav elengths from 1.52 mu m to 1.59 mu m, a range comparable to the expand ed Er-doped fiber amplifier gain band. A newly developed held-size-var iation electron-beam lithography enables grating pitch to be controlle d to within 0.0012 nm, and narrow-stripe selective metal-organic vapor -phase epitaxy is used to control the bandgap wavelength of laser acti ve layers and modulator absorption layers for each channel. The channe l spacing of fabricated 40-channel DFB/MODs is 214 GHz in average with a standard deviation of 0.39 nm. Very uniform lasing and modulating p erformances are achieved, such as threshold currents about 10 mA and e xtinction ratios about 20 dB at -2 V in average. These devices have be en used to demonstrate 2.5-Gb/s transmission over 600 km of a normal f iber with a power penalty of less than 1 dB.