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

Abstract

We report on a study of polarization properties of asymmetric, multimode vertical-cavity surface-emitting lasers (VCSEL) subjected to electrical RF modulation. When subjected to RF modulation, complex frequency-dependent polarization properties, especially near the polarization switching point are revealed. We propose a scheme of rapidly switching the two RF frequencies modulating the VCSEL, in order to achieve fast polarization modulation in these VCSEL. Polarization modulation up to 300 MHz by modulating the RF frequency and up to 1.5 GHz with RF power modulation has been demonstrated; the fastest reported electrically controlled polarization modulation for multimode VCSELs.

Vertical-cavity surface-emitting laser with a liquid crystal external cavity

“…Different ways to achieve this have been intensively studied. Theoretical and experimental results on controlling the transverse modes, polarization states, and longitudinal modes of VCSELs have been reported [1][2][3][4][5][6][7][8][9][10][11]. From a theoretical analysis of the operation of a VCSEL with an external cavity [3,4], the polarization mode can be switched by either changing the strength (or the delay) of the optical feedback (OF) or using a currentdependent thermal effect.…”

“…From a theoretical analysis of the operation of a VCSEL with an external cavity [3,4], the polarization mode can be switched by either changing the strength (or the delay) of the optical feedback (OF) or using a currentdependent thermal effect. Polarization switching is realized by current injection [5], phase change in the external cavity [6], temperature [7], frequency modulation [8], or optical injection [9,10]. A liquid crystal (LC) is used in VCSELs to obtain a tunable lasing wavelength [11].…”