Free carrier effects in a modulation-doped GaAs QW placed in the n-region of a p-n junction were successfully used to obtain active Q-switching in a two-section GaAs/AIGaAs DH laser structure. The modulator-section uses the blue shift of the QW absorption edge due to band filling by a 2D electron gas which concentration could be controlled between 0 and 8 x 1011 cm2 by external bias voltage. Only about 100 mV of the modulating voltage was necessary to provide stable active Q-switching. The threshold injection current density ranged from 400 to 800 A/cm2 .The modulation bandwidth estimated to be not less than 4 -5 GHz. A simple electrostatic model is suggested to describe electrooptical phenomena in a modulation-doped QW which underlie the operation of the device.

Date Published: 26 June 1992
PDF: 9 pages
Proc. SPIE 1634, Laser Diode Technology and Applications IV, (26 June 1992); doi: 10.1117/12.59164

Published in SPIE Proceedings Vol. 1634:
Laser Diode Technology and Applications IV
Daniel S. Renner, Editor(s)