CONTROL OF LIGHT POLARIZATION IN INGAASP INP LASERS BY INJECTION OF LIGHT-PULSES/

Light emission from a ridge waveguide 1.3 mu m InGaAsP/InP semiconduct or laser pumped both electrically and optically was analyzed by polari zation- and time-resolved measurements. The electric and the optical e xcitation was realized with a de-bias current and with 150 ps pulses f rom a Q-switched Nd-YAG laser at 1.064 mu m wavelength, respectively. The pump light was introduced into the InGaAsP/InP laser through a win dow opened in the substrate gold contact. The steady-state P-1 charact eristics of the semiconductor laser exhibited a transition from TM- to TE-polarized light emission if the injection current surpasses a cert ain value that depends on the heatsink temperature. Depending on the d c-bias current and the optical pulse power, a variety of different emi ssion characteristics of the semiconductor laser were observed: pure T E or TM pulsations, in combination with a background cw emission in so me cases; simultaneous emission of TE and TM pulses and switching betw een TM and TE emission states with switching times as short as 30 ps. (C) 1997 American Institute of Physics.