Polarization-selective Feedback Research Articles

Low-Frequency Fluctuations in Vertical-Cavity Surface-Emitting Lasers With Polarization Selective Feedback: Experiment and Theory

We present theory and measurements on a vertical-cavity surface-emitting laser (VCSEL) biased close to its solitary threshold and subject to polarization selective external optical feedback. The system shows low-frequency fluctuations (LFF) in the selected polarization mode (PM). Below solitary laser threshold, the orthogonal PM remains silent, while it only responds after a dropout event in the main mode above threshold. Our calculations show good agreement with the measurements and identify a type of synchronization between the low-frequency dynamics of the two PMs.

Complex polarization dynamics in a VCSEL with external polarization-selective feedback

Complicated dynamical regimes are found in a vertical-cavity surface-emitting laser with polarized optical feedback. The dynamics depends on the interplay between the intrinsic and external anisotropies that determine the strength of the coupling (and mixing) of the orthogonally polarized eigenstates of the solitary laser. When there is anisotropic feedback for emission initially on one eigenstate, low-frequency pulsations arise via excitation of the field of the second eigenstate.

Modelling of switching and stability of vertical-cavity lasers with polarization-selective feedback

Polarization-selective feedback into one of the two linearly polarized modes of emission of a quantum-well vertical-cavity laser is studied theoretically to determine domains of bistability and spontaneous switching as the strength and phase of the optical feedback are varied. Feedback enlarges the domains of instability, enhances the domains of time-dependent polarization and creates more complicated phase-space dynamics when the feedback is sufficiently strong to create multiple steady-state solutions.

Raman polarization-selective feedback schemes for all-optical microwave frequency standards

All-optical locking of the frequency difference between two laser diodes onto a Raman transition is demonstrated. The properties of Raman-type polarization spectroscopy are discussed and exemplified in the cases of the 3.036 GHz Raman resonance of the 85Rb D2 line. The generation of a polarization-selective Raman resonant optical feedback ensures the Raman optical locking of the slave diode laser onto the master oscillator.