Analysis of the polarization of single-mode vertical-cavity surface-emitting lasers subject to parallel optical injection

Abstract

We investigate experimentally and theoretically the polarization switching found in a single-transverse mode VCSEL when subject to parallel optical injection. Our analysis focuses on a recently observed state in which injection locking of the parallel polarization and excitation of the free-running orthogonal polarization of the VCSEL are obtained. A simple nonlinear dependence between the power of both linear polarizations and the frequency detuning is found. Also the total power emitted by the VCSEL is constant and independent on the injected optical power and on the frequency detuning. We check these results experimentally for a variety of frequency detunings and bias currents applied to the device. We report experimental and theoretical stability maps in the injected power-frequency detuning plane for different bias currents identifying the regions in which the state is observed. A simple analytical expression that describes the map boundary for large and negative frequency detunings is obtained. This provides a simple method to extract the linear dichroism of the device.

Attractor hopping between polarization dynamical states in a vertical-cavity surface-emitting laser subject to parallel optical injection

“…5(i) and shows that the system stays for some microseconds on the P1 state (τ 1 ), whereas the stay on the IL+PS state, given by τ 2 , can vary from 5 μs to 10 ms. This panel was obtained for the injection parameters ν i = 1.1 GHz and P i = 64.71 μW, which is close to the region where IL+PS is observed [47,48,50].…”

“…P1-both is characterized by an anticorrelated limit cycle appearing simultaneously in both polarizations with frequencies of 3.3 and 3.4 GHz, and centered on the injected light frequency and the free-running orthogonal mode, respectively. Finally, IL+PS, which has been widely discussed in our previous work [47,48], shows the locking of the parallel polarization to the injected light, and a simultaneous excitation of the orthogonal polarization mode. These three types of nonlinear dynamics will appear in the attractor hopping discussed in Sec.…”

“…Experimentally we attain parallel optical injection in the VCSEL by using the all-fiber setup illustrated in Fig. 1(a) and described in detail in [48][49][50]. More specifically, we inject the parallely polarized light from our tunable master laser into the slave laser, which is a long-wavelength 1550-nm VCSEL, through an optical circulator.…”

“…↔ 565.76 μW] [49]. We also take the value of the linear dichroism, γ a = −0.21 ns −1 , that corresponds to I bias = 3.0 mA [48], and a fraction of spontaneously emitted photons that are coupled into the laser mode, β SF = 2.7 × 10 −4 . Figure 8(a) shows the theoretical time traces of the power of both linear polarizations.…”

“…Recently, the polarization nonlinear dynamics of a singlemode VCSEL subject to parallel optical injection has been studied in experimental and theoretical ways [47][48][49][50]. In the parallel optical injection the directions of linear polarization of the injected light and the free-running VCSEL are parallel.…”