POLARIZATION SWITCHING IN A TENSILE-STRAINED INGAAS INGAASP MULTIPLE-QUANTUM-WELL DISTRIBUTED-FEEDBACK LASER-DIODE/

An inhomogeneously biased distributed feedback (DFB) laser diode (LD) with two electrodes switched its polarization mode by 3 mA change of t he bias current, maintaining single longitudinal mode oscillation. In the active layer of the LD, 13 nm thick and 0.6% tensile-strained InGa As multiple quantum well (MQW) equalized the transverse electric and t he transverse magnetic modal optical gain at 1.55 mu m. With various g rating pitches on the same MQW active layer, polarization switching DF B LDs were realized in the wavelength range as wide as 18 nm. The line width characteristics during the polarization switching were confirmed to be narrow due to the small switching current. (C) 1998 American In stitute of Physics.