Suppressing the Nonlinearity of Free Running VCSEL Using Selective-Optical Feedback

In this letter, the nonlinear dynamics of a vertical-cavity surface-emitting laser (VCSEL) subjected to the optical feedback and a modulation signal is investigated experimentally. For this purpose, orthogonal polarization optical feedback (OOF) and parallel polarization optical feedback, which are defined by a T-shaped feedback scheme, are employed. The result obtained show that the nonlinearity of the VCSEL is entirely supressed and the 3-dB bandwidth is enhanced with the OOF. We show that the harmonics distortions are significantly improved with the 2
^nd
, 3
^rd
, and 4
^th
harmonics components of the VCSEL's polarization modes reduced to the noise floor. Essentially, the OOF is proposed as a new tool to improve the linear dynamic range and the analogue performance of the VCSEL.