Controllable spiking patterns in long-wavelength VCSELs for neuromorphic photonics systems

Multiple controllable spiking patterns are obtained in a 1310 nm Vertical Cavity Surface Emitting Laser (VCSEL) in response to induced perturbations and for two different cases of polarized optical injection, namely parallel and orthogonal. Achievement of reproducible spiking responses in VCSELs operating at the telecom wavelengths offers great promise for future uses of these devices in ultrafast neuromorphic photonic systems for non-traditional computing applications.Comment: 10 pages, 6 figures, journal submissio

Control of emitted light polarization in a 1310 nm dilute nitride spin-vertical cavity surface emitting laser subject to circularly polarized optical injection

We experimentally demonstrate the control of the light polarization emitted by a 1310 nm dilute nitride spin-Vertical Cavity Surface Emitting Laser (VCSEL) at room temperature. This is achieved by means of a combination of polarized optical pumping and polarized optical injection. Without external injection, the polarization of the optical pump controls that of the spin-VCSEL. However, the addition of the externally injected signal polarized with either left- (LCP) or rightcircular polarization (RCP) is able to control the polarization of the spin-VCSEL switching it at will to left- or right-circular polarization. A numerical model has been developed showing a very high degree of agreement with the experimental findings

Nonlinear dynamics of Long-Wavelength VCSELs subject to polarised optical injection

We present our work analysing the effects of polarised optical injection in Long-Wavelength Vertical-Cavity Surface Emitting Lasers (LW-VCSELs). We review the properties of different phenomena such as polarisation switching (PS) and bistability (PB) as well as on the different nonlinear dynamics (periodic and chaotic) arising in these devices under different cases of polarised optical injection. © 2011 IEEE

Simulated dynamics of optically pumped dilute nitride 1300 nm spin vertical-cavity surface-emitting lasers

The authors report a theoretical analysis of optically pumped 1300 nm dilute nitride spin-polarised vertical-cavity surface-emitting lasers (VCSELs) using the spin-flip model to determine the regions of stability and instability. The dependence of the output polarisation ellipticity on that of the pump is investigated, and the results are presented in twodimensional contour maps of the pump polarisation against the magnitude of the optical pump. Rich dynamics and various forms of oscillatory behaviour causing self-sustained oscillations in the polarisation of the spin-VCSEL subject to continuouswave pumping have been found because of the competition of the spin-flip processes and birefringence. The authors also reveal the importance of considering both the birefringence rate and the linewidth enhancement factor when engineering a device for high-frequency applications. A very good agreement is found with the experimental results reported by the authors' group. © The Institution of Engineering and Technology 2014

Circular polarization switching and bistability in an optically injected 1300 nm spin-vertical cavity surface emitting laser

We report the experimental observation of circular polarization switching (PS) and polarization bistability (PB) in a 1300 nm dilute nitride spin-vertical cavity surface emitting laser (VCSEL). We demonstrate that the circularly polarized optical signal at 1300 nm can gradually or abruptly switch the polarization ellipticity of the spin-VCSEL from right-to-left circular polarization and vice versa. Moreover, different forms of PS and PB between right- and left-circular polarizations are observed by controlling the injection strength and the initial wavelength detuning. These results obtained at the telecom wavelength of 1300 nm open the door for novel uses of spin-VCSELs in polarization sensitive applications in future optical systems

Controlled Single- and Multiple-Pulse Excitability in VCSELs for Novel Spiking Photonic Neurons

Excitability in VCSELs under parallel- and orthogonally-polarized optical injection is investigated numerically. Controlled single- and multiple-pulse excitability is found for the two polarizations offering prospects for novel VCSEL-based ultrafast spiking photonic neurons

Instabilities in Spin-Polarized Vertical-Cavity Surface-Emitting Lasers

We report a first comprehensive theoretical analysis of optically pumped spin-polarized vertical-cavity surface-emitting lasers, which combines the spin-flip model with the largest Lyapunov exponent technique to determine regions of stability and instability. The dependence of these regions on a wide range of fundamental device parameters is investigated, and results were presented in a new form of maps of the polarization versus the magnitude of the optical pump. We also reveal the importance of considering both the birefringence rate and the linewidth enhancement factor when engineering a device for high-frequency applications. © 2011 IEEE

Polarized optical injection in long-wavelength vertical-cavity surface emitting lasers

We report a comprehensive study of the effects of polarized optical injection in long-wavelength Vertical-Cavity Surface Emitting Lasers (LW-VCSELs) emitting at the telecom wavelength of 1550nm. We analyze the properties of the polarization switching and bistability that can be induced in a 1550nm-VCSEL under orthogonal and arbitrary polarized optical injection. Additionally, we study the injection locking bandwidth of these devices when subject to different polarized optical injection. Furthermore, we also analyze the relationship existing between the injection locking bandwidth and the polarization switching range when the device is subject to orthogonally-polarized optical injection. Finally, we have identified regions of different nonlinear dynamics outside the injection locking bandwidth, including regions of periodic dynamics (such as limit cycle and period doubling) and chaos when these devices are subject to parallel and to orthogonal optical injection. This rich variety of nonlinear effects observed at 1550nm offers exciting prospects for novel practical uses of VCSELs in optical switching/routing applications in optical networks. © 2011 SPIE

Elliptical injection of a 1550nm-VCSEL : theory and experiment

We show new theoretical results on polarized optical injection of VCSELs based on the spin flip model extended to consider both the azimuth and ellipticity of the injected light, and demonstrate excellent agreement with experiment