Experimental Study of Transverse Mode Selection in VCSELs Induced by Parallel Polarized Optical Injection (original) (raw)
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The output polarization of vertical cavity surface emitting lasers (VCSELs) has been investigated experimentally using external optical injection. The frequency, intensity and polarization state of the injected beam will determine how the parameters of the VCSEL are changed. The polarization of the VCSEL emission can be changed from linear horizontally polarized to a circularly or elliptically polarized state using low power circularly polarized optical injection, with frequency detuning around -10 GHz with respect to the slave laser frequency at threshold. In addition the optical injection will reduce the threshold lasing current compared to that of the stand-alone VCSEL.
IEEE Journal of Quantum Electronics, 2007
In this paper, we report on theoretical and experimental investigation on polarization and transverse mode behavior of vertical-cavity surface-emitting lasers (VCSELs) under orthogonal optical injection as a function of the injection strength and of the detuning between the injection frequency and the free-running frequency of the solitary laser. As the injection strength increases the VCSEL switches to the master laser polarization. We find that the injection power necessary to obtain such polarization switching is minimum at two different values of the frequency detuning: the first one corresponds to the frequency splitting between the two linearly polarized fundamental transverse modes, and the second one appears at a larger positive frequency detuning, close to the frequency difference between the first-order and the fundamental transverse modes of the solitary VCSEL. We show theoretically that both the depth and the frequency corresponding to the second minimum increase when the relative losses between the two transverse modes decrease. Bistability of the polarization switching is obtained for the whole frequency detuning range. Such a bistability is found for the fundamental mode only or for both transverse modes, depending on the value of the detuning. The theoretical and experimental optical spectra are in good agreement showing that the first-order transverse mode appears locked to the external injection.
Journal of The Optical Society of America B-optical Physics, 2017
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.
Lasing Characteristics of VCSELs Subject to Circularly Polarized Optical Injection
IEEE/OSA Journal of Lightwave Technology, 2011
This paper reports experimental investigations of the effects of circularly polarized optical injection on the lasing characteristics of vertical-cavity surface-emitting lasers (VCSELs). The operating characteristics of the target VCSELs are changed using available optical injection control parameters including the strength and polarization state of the optical injection as well as the frequency detuning between the injected light and the target VCSEL. Using circularly polarized optical injection with frequency detuning around -10 GHz, the linear output polarization of the stand-alone VCSEL can be converted into circularly polarized or elliptically polarized emission when the VCSEL drive current is close to or below the threshold current of stand-alone VCSEL. In addition, highly nonlinear light-current characteristics are observed in the optically injected VCSEL in the vicinity of threshold.
Two-frequency injection on a multimode vertical-cavity surface-emitting laser
Optics Express, 2011
We have studied experimentally effects of two-frequency optical injection on a multimode vertical-cavity surface-emitting laser (VCSEL). The injected signal comes from another VCSEL. Polarization switching (PS) with and without frequency locking occurs for relatively small frequency detuning. Outside the regime of polarization switching, the VCSEL demonstrates two types of instabilities. The instability regions and boundaries of PS of each transverse mode are mapped in the parameter plane of frequency detuning versus injected power.
IEEE Journal of Quantum Electronics, 2006
In this paper, the output characteristics of an oxide-confined AlGaAs-As quantum well vertical-cavity surfaceemitting laser (VCSEL) under orthogonal optical injection are mapped as a function of the strength of the optical injection and the detuning between the injection frequency and the free-running frequency of the solitary laser, for a very large range of frequency detuning (from 82 to 89 GHz). The injection light is polarized orthogonally with respect to the solitary VCSEL output light. As the injection strength increases the VCSEL switches to the master laser polarization. Polarization switching is accompanied by a rich nonlinear dynamics, including limit cycle, wave mixing, subharmonic resonance and period doubling route to chaos. Polarization switching is found with but also without injection locking. Injection locking occurs with the slave fundamental transverse mode or, for large positive detunings, with the first-order transverse mode.
Injection locking and polarization switching in a 1550-nm VCSEL under parallel optical injection
2015
We report an experimental study of the injection locking regime and the polarization switching in a single mode Vertical-Cavity Surface-Emitting laser (VCSEL) under parallel optical injection when we inject around the parallel polarization frequency of the solitary VCSEL. We have analyzed the results for high and low injected values of the power. Also we have analyzed the effect of decreasing and increasing the frequency detuning for a fixed value of the injected power. Different bistable behaviors have been observed depending on the value of the injected power.
Optics letters, 2016
Polarization switching in a long-wavelength vertical-cavity surface-emitting laser (VCSEL) under parallel optical injection is analyzed in a theoretical and experimental way. For the first time, to our knowledge, we report experimentally a state in which injection locking of the parallel polarization and excitation of the free-running orthogonal polarization of the VCSEL are simultaneously obtained. We obtain very simple analytical expressions that describe both linear polarizations. We show that the power of both linear polarizations depend linearly on the injected power in such a way that the total power emitted by the VCSEL is constant. We perform a linear stability analysis of this solution to characterize the region of parameters in which it can be observed. Our measurements qualitatively confirm the previous theoretical predictions.
2011
The authors have studied the effects of polarised optical injection in a 1550 nm vertical-cavity surface-emitting laser (VCSEL) operated at currents up to 4.5 times threshold. Regions of stable injection locking have been measured for cases where the injected signal is polarised to match one of the two polarisations of the fundamental transverse mode of the solitary VCSEL. In addition regions of polarisation switching have been found for the case where the input polarisation is matched to that of the subsidiary mode of the solitary ...
Optics Express, 2010
We report a first experimental study of the nonlinear dynamics appearing in a 1550 nm single-mode VCSEL subject to parallel and to orthogonal optical injection. For the first time to our knowledge we report experimentally measured stability maps identifying the boundaries between regions of different nonlinear dynamics for both cases of polarized injection. A rich variety of nonlinear behaviours, including periodic (limit cycle, period doubling) and chaotic dynamics have been experimentally observed.