High-frequency polarization self-modulation in vertical-cavity surface-emitting lasers

Abstract

Polarization self-modulation at frequencies up to 6 GHz is observed in a vertical-cavity surface-emitting laser. This self-oscillation is observed when a portion of the laser output power is injected back into the laser after having rotated its polarization by 90° with respect to the initial laser polarization state. Our experiment demonstrates a simple technique for generating an ultrahigh frequency optical clock. New applications in optical storage are also envisioned.

Polarization dynamics in vertical-cavity surface-emitting lasers with optical feedback through a quarter-wave plate

“…1,4 Here, we consider the behavior of a VCSEL under polarization-changing optical feedback, simulating the experimental situation described in Ref. 1. The external cavity is formed by the VCSEL and a partial reflector, and a quarter-wave plate is inserted inside the cavity with its axes rotated by 45°with respect to the polarization basis states of the VCSEL.…”

“…The polarization-state selection, the polarization dynamics, and the polarization switching in VCSELs can be changed by optical injection, 2 current modulation, 3 and by polarizationsensitive optical feedback. 1,4 Here, we consider the behavior of a VCSEL under polarization-changing optical feedback, simulating the experimental situation described in Ref. 1.…”

“…For many experiments, when the excitation is just above the lasing threshold, one linear polarization dominates; and when the pump current is increased to about 20%-30% above threshold, the emission switches to the orthogonal linear polarization. 1 The two linearly polarized states typically have different frequencies split by a few GHz by the material birefringence. The change of polarization state has attracted considerable interest because of its potential applications in optical switching.…”

Square-wave switching in vertical-cavity surface-emitting lasers with polarization-rotated optical feedback: Experiments and simulations

“…An optical feedback scheme that has received a lot of attention has been referred to as polarization-rotated (PR) feedback or orthogonal feedback [5][6][7][8][9][10][11][12][13][14]. In this scheme a 90-deg polarization-rotating device is placed in the external cavity, and thus, the associated linear orthogonal polarizations (in the following referred to as x and y) are mutually fed back: x-polarized light is reinjected into the laser as y-polarized light after a delay time τ , and vice versa.…”

Two-parameter study of square-wave switching dynamics in orthogonally delay-coupled semiconductor lasers

“…The increase in the feedback/coupling strength typically destabilizes the otherwise steady dynamics to self-pulsation with a period either close to the laser relaxation oscillation frequency or to the feedback/coupling delay time [1]. The waveform can vary from sharp pulsing to harmonic to square wave (SW) depending on the system nonlinearity [2][3][4][5], on the sub-or super-critical nature of the underlying Hopf bifurcation [5,6], on the laser mode competition or on the coupling/feedback parameters [7][8][9][10][11][12][13][14][15]. An interesting combination of these parameters is found in a recent experiment, where two edge-emitting laser diodes are mutually coupled through their orthogonal polarization modes [16].…”