Polarization Bistability Induced by Orthogonal Optical Injection in 1550-nm Multimode VCSELs

We have analyzed experimentally the optical power polarization bistability induced in a long-wavelength multitransverse mode vertical-cavity surface-emitting laser (VCSEL) under orthogonal optical injection. Bistability with very wide hysteresis cycles is measured for both the fundamental and the high-order transverse mode of the device. The shape of the associated hysteresis cycle is different for each of the two transverse modes. The power of the parallel polarized high-order (fundamental) transverse mode remains constant (gradually decreases) as the injected power is increased. Both powers suddenly drop to low levels at large values of the injected power. The squared shape measured for the I/O characteristic of the high-order transverse mode is of particular interest for obtaining good quality all-optical inversion and all-optical regeneration for use in optical telecommunication networks.