Stable polarization self-modulation in vertical-cavity surface-emitting lasers

Abstract

The characteristics of polarization self-modulation in a vertical-cavity surface-emitting laser (VCSEL) were studied for frequencies up to ≈9 GHz both experimentally and theoretically. Polarization self-modulation was obtained by rotating the linearly polarized output of the VCSEL by 90° and reinjecting it into the laser. Experimentally we simultaneously recorded time traces, optical and radio-frequency spectra. We found for increasing modulation frequencies that the output characteristics changed from square-wave to sinusoidal and the VCSEL system assumed new polarization eigenstates that are different from the free-running VCSEL eigenstates. We modeled polarization self-modulation as an interband process and found a good qualitative agreement between our experimental and numerical results.

Numerical analysis of a dual polarization mode-locked laser with a quarter wave plate

“…Another phenomenon is the polarization self-modulation (PSM) which results from the insertion of a quarter wave plate (QWP) into the laser cavity [3,4]. This dynamical behavior is also found in some couple cavity lasers such as a VCSEL subject to an optical feedback passing through a QWP [5][6][7][8][9][10][11]. Both experimental results and theoretical analysis all reveal that PSM is attributed to the frequency shift between the eigenmodes in the neutral axes of QWP [3,9,12].…”

Robust square-wave polarization switching in vertical-cavity surface-emitting lasers

“…In fact, while semiconductor lasers offer many advantages as photonic sources, signal generation via modulation of the injection current requires high-speed electronics and is limited in bandwidth due to the electrical characteristics of the laser diode and its mounting. Alternative solutions have been proposed where the laser emission is governed by a dynamical regime induced by either the presence of optical feedback [2,3], coupling to other lasers [4], optical injection [5,6], or polarization-rotated optical feedback [7,8]. The advantage of these solutions is that they are selfsustained and robust, provided that their stability range is sufficiently extended in the parameter space of the system considered.…”

“…Polarizationrotated optical feedback-where the two linearly polarized components, LP-x and LP-y, of the light emitted by the device are fed back into the laser cavity after the LP-x component is converted into the LP-y component and vice versa-induces a regular polarization dynamics which can be as fast as 9 GHz [7,8].…”

Different regimes of low-frequency fluctuations in vertical-cavity surface-emitting lasers

“…5 However, the polarization properties of VCSELs also lead to new and interesting phenomena when VCSEL are coupled to an external cavity. We can cite, for example, polarization-switching phenomena in polarized optical feedback, 6,7 polarization self-modulation in VCSELs coupled to optical feedback through a quarter-wave plate, [8][9][10][11][12][13][14] optical-feedbackinduced polarization mode hopping, and generalized multistability. 15 New applications of VCSELs for optical telecommunications may be proposed based on these delay-induced dynamics.…”