Polarization of the output of InGaAsP semiconductor diode lasers

Measurements of the degree of polarization ( rho ) of the output of 1.3- mu m InGaAsP semiconductor diode lasers as a function of current are discussed. It is found that rho measured for well below threshold ( rho /sub b/) is a better indicator of mechanical strain in the active region than rho measured near or above threshold. rho /sub b/ exhibits little dependence on drive level, mode reflectivity, threshold, or saturation of the gain. A possible correlation between the magnitude of rho /sub b/ and device operating characteristics was found. More work is required to confirm this possibility. Data which provide experimental evidence for the magnitude of the difference between the reflectivities of the TE and TM modes are presented.<>