Effects of parallel and orthogonal polarization on nonlinear optical characteristics of a 1550 nm VCSOA

Experimental observation of Optical Bistability (OB) and nonlinear gain is reported in a 1550-nm Vertical Cavity Semiconductor Optical Amplifier (VCSOA) under parallel and orthogonal polarized optical injection into the two orthogonal polarizations of the fundamental mode. Different nonlinear switching mechanisms, including anticlockwise and clockwise nonlinear gain and bistability, have been found when the polarization of the externally injected signal matches that of the injected mode, whilst a linear response is measured when the polarization is orthogonal to that of the mode under injection. This diversity of behavior with input polarization offers promise for the potential use of VCSOAs for all-optical signal processing and all-optical switching/routing applications.