Measuring the above-threshold group-velocity dispersion and gain curvature of a semiconductor laser by pulse-propagation techniques

Abstract

The dispersive broadening of a single optical pulse traveling within a Fabry–Pérot semiconductor laser was measured for propagation over 58 round trips of the cavity, a distance of 352 mm. The interference between two copropagating pulses with variable relative phase (stabilized to within $2\pi \times 0.02 \mathrm{rad})$ was used to relate the group-velocity dispersion to the gain curvature. With both single- and double-pulse propagation measurements, the complex group-velocity dispersion (including gain curvature) was found to be $8.7+5.9i {\mathrm{ps}}^2/\mathrm{m}$ at twice the laser-threshold bias current. When the laser bias was increased from 1.4 to 2 times the laser threshold, the gain curvature decreased by 2.8%, and the group-velocity dispersion showed less than 0.1% variation.

© 2004 Optical Society of America