Polarization Bistability in 1550 nm Wavelength Single-Mode Vertical-Cavity Surface-Emitting Lasers Subject to Orthogonal Optical Injection

In this paper, we report on an experimental investigation of the bistable behavior of a 1550 nm single transverse and polarization mode vertical-cavity surface-emitting laser (VCSEL) when subjected to orthogonal optical injection. As the master laser wavelength is scanned near the resonance wavelength of the depressed linearly polarized fundamental mode, and for a fixed injected power, the VCSEL exhibits two successive polarization switchings (PSs). Both PSs exhibit bistable regions in such a way that a pure-frequency-induced polarization bistability is found. The width of both bistable regions has been measured as a function of the injected power and for different values of the VCSEL current. While the injection power is lesser than a certain value, the hysteresis width fluctuates around a constant level. Further increase of the injection power leads to a smaller constant value of the hysteresis width. The value of that transition value is independent of the VCSEL current. Power-induced polarization bistability - by fixing the master laser wavelength - is found near the transition value. Clockwise and anticlockwise power-hysteresis cycles are observed for short and long master laser wavelengths, respectively.