Jjm. Binsma et al., CHARACTERIZATION OF BUTT-JOINT INGAASP WAVE-GUIDES AND THEIR APPLICATION TO 1310NM DBR-TYPE MQW GAIN-CLAMPED SEMICONDUCTOR OPTICAL AMPLIFIERS, IEICE transactions on electronics, E80C(5), 1997, pp. 675-681
Butt-joint waveguide couplings are fabricated for use in InP-based pho
tonic integration, and characterized by scanning electron microscopy a
nd optical transmission measurements. Several parameters have been opt
imized in the characterization study: size and shape of the mask prote
cting the first waveguide layer during butt-joint regrowth, and the cr
ystallographic direction of the butt-joint interface. The studies show
that high-quality butt-joints having negligible optical loss can be m
ade with good fabrication tolerance. Using the optimized butt-joint, D
BR-type, gain-clamped SOAs have been fabricated which are free of inte
rnal -excess- reflections. A constant optical gain of 21 dB is obtaine
d up to a signal output power of 25 mW. The devices show CATV grade li
nearity in a 77 channel CATV linearity test at a distortion level of -
55 dB below carrier.