Polarization bistability in 1.5 micron wavelength single-mode vertical-cavity surface-emitting lasers induced by orthogonal optical injection

摘要

We study experimentally the polarization Instability of a single transverse and polarization mode vertical-cavity surface-emitting laser (VCSEL) induced by orthogonal optical injection. As the master laser frequency is scanned near the resonance frequency of the depressed linearly polarized fundamental-mode, and for a fixed master laser power, the VCSEL exhibits two successive polarization switchings. Pure frequency-induced polarization bistability is found because both polarization switchings exhibit bistable regions. The width of both bistable regions is analyzed as a function of the master laser power and for different values of the VCSEL current. The hysteresis width fluctuates around a constant level while the injected power is smaller than a certain value. Further increase of the master laser power leads to a smaller constant value of the hysteresis width. The value of that transition value is independent on the VCSEL current. Power-induced polarization bistability -by fixing the frequency of the injected light- is found near that transition value. The character of the power-hysteresis cycles change from clockwise to anticlockwise as the master laser frequency moves away from the frequency of the depressed linearly polarized fundamental-mode. Qualitatively similar results are found for different VCSELs with wavelength around 1550 nm.