Evaluation of performance capabilities of emitters and detectors based on a common MQW structure

Photodetectors (PDs) based on three separate confinement-multiple quantum w ell (SCH-MQW) structures (with 2, 4 and 8 QWs) and sis graded-index (GRIN) SCH-MQW structures were studied for two types of devices: guided wave and n on-guided wave devices. Non-guided wave devices were processed and the capa citance and the responsivity, in the wavelength range of 750-990 nm, were d etermined for various bias voltages. Guided wave PDs were simulated using t he transfer matrix method for optical mode calculation and the minimum leng th of the detectors was calculated for absorbing 99% of the incident light. The junction capacitance of the guided wave PDs was calculated from the me asured capacitance of non-guided wave devices and the minimum size of the d evices, values of 215, 101, and 52 fF were obtained for 2, 4 and 8 QW SCH-M QW structures. Laser diodes were also fabricated from the three different S CH-MQW structures. Threshold current densities (J(th)) of 737. 755 and 1210 A cm(-2) were measured for 2, 4 and 8 QWs, respectively. Further improveme nt was achieved using GRINSCH-MQW structures and LDs with 4 QWs exhibited 3 3% decrease in J(th) and 22% increase in slope efficiency. (C) 2001 Elsevie r Science B.V. All rights reserved.