Abstract

Optical phase conjugation through nearly degenerate four-wave mixing (NDFWM) in semiconductor lasers has attracted considerable attention since being first demonstrated by Nakajima and Frey [1]. Such interest arises due to the very high conjugate reflectivity of order 30- 40dB which can be achieved owing to the amplifying effect of the semiconductor gain medium and cavity enhancement of mixing process. Moreover, the laser diode provides a mixing medium with a very intense pump beam already in the cavity, so only one external probe power is required. In addition, when the frequency detuning between the probe and pump beams is a multiple of the cavity frequency, the spectral response of conversion efficiency versus the frequency detuning exhibits resonant peaks. Experiments show that both a high conversion efficiency(>10 dB) and a large step-tunable frequency detuning over a range(>2.5THz) can be achieved by using cavity-enhanced NDFWM in a semiconductor laser[2]. So investigation of Fabry-Perot laser structures in which NDFWM can be optimized is of significant practical interest. NDFWM in multisection laser diodes has been studied theoretically[3]. However, there is little experimental work on NDFWM in two-section single cavity Fabry-Perot (TSSC FP) laser diodes. This paper is focused on an experimental study of NDFWM in a TSSC FP laser diode for different probe injection powers. We present results on the conjugate reflectivity dependence of the frequency detuning subject to different injection power. It is shown that the conjugate reflectivity is dependent on optical probe injection into either section of a TSSC FP laser diode, injection power and bias current condition.

© 2000 IEEE