Gain-dependent polarization properties of vertical-cavity lasers

Abstract

Abstract-We show that the partitioning of power into the two orthogonal eigen polarizations of infra-red gain-guided verticalcavity lasers depends upon the relative spectral overlap of the nondegenerate polarization cavity resonances with the laser gain spectrum. Furthermore, at the condition where the polarization resonances and the peak laser gain are aligned, abrupt switching of power between the eigen polarizations is observed as the gain sweeps through the polarization resonances. The gain-dependence of the polarization requires spectral splitting between the eigen polarizations, which is found to be strongly influenced by local strain. The polarization of the fundamental and higher-order spatial modes can be selected and maintained for all InGaAs vertical-cavity lasers in a wafer simply by employing a 20 nm or greater blue-shift offset of the peak laser gain relative to the cavity resonances.

Fast, electrically controlled polarization modulation of multimode vertical-cavity surface-emitting lasers by RF frequency modulation

“…Polarization properties of VCSELs are extremely interesting and yet, poorly understood. It is well known [1] that VCSELs generally exhibit abrupt polarization switching as a function of bias current, from higher to lower frequency mode (type-I switching) or vice-versa (type-II switching), depending on the detuning between the polarization modes and their relative position with respect to the gain spectrum [2]. It has also been found that the VCSEL polarization can be affected by the temperature [2], magnitude and directionality of current injection [3][4][5][6], stress [7] and with polarized optical injection.…”

“…It is well known [1] that VCSELs generally exhibit abrupt polarization switching as a function of bias current, from higher to lower frequency mode (type-I switching) or vice-versa (type-II switching), depending on the detuning between the polarization modes and their relative position with respect to the gain spectrum [2]. It has also been found that the VCSEL polarization can be affected by the temperature [2], magnitude and directionality of current injection [3][4][5][6], stress [7] and with polarized optical injection. Theoretical modeling based on 'Spin-Flip Model' [8,9] has been successfully used to predict certain static [10,11] and dynamic [12][13][14] polarization properties of VCSELs.…”

Nonvolatile polarization control of a bistable VCSEL

“…Residual dichroism and birefringence, which are inevitably present, lead to different net gains of the polarization modes, thus slightly favoring one mode over the other at VCSEL threshold. Nevertheless, polarization switching and instabilities occur when changing VCSEL control parameters [5,6]. The most striking evidence is usually obtained in the Light output (L) vs. Pumping Current (I) curve (L/I curve),where, at a given current value, an abrupt switch occurs from one linear polarization (LP) state to the orthogonal one, often accompanied by a narrow hysteresis cycle.…”

Experimental Study of Transverse Mode Selection in VCSELs Induced by Parallel Polarized Optical Injection

“…Emission in different polarization and transverse modes is usually found in solitary VCSELs. While the multitransverse mode emission is attributed to Spatial Hole Burning (SHB) effects [28][29][30], the polarization behavior of VCSELs can be influenced by a number of physical mechanisms [31][32][33][34]. Optical injection experiments have been usually performed using two different configurations.…”