Michael R. Kossey

End-fire silicon optical phased array with half-wavelength spacing

We demonstrate an optical phased array with emitting elements spaced at half the operational wavelength. The device is a one-dimensional array fabricated on an integrated silicon platform for operation at a wavelength of 1.55 μm. Light is emitted end-fire from the chip edge where the waveguides are terminated. The innovative design and high confinement afforded by the silicon waveguides enables λ/2 spacing (775-nm pitch) at the output thereby eliminating grating lobes and maximizing the power in the main lobe. Steering is achieved by inducing a phase shift between the waveguide feeds via integrated thermo-optic heaters. The device forms a beam with a full-width half-maximum angular width of 17°, and we demonstrate beam steering over a 64° range limited only by the element factor.

Light transport through ultrafast chaotic micro-cavities for photonic physical unclonable functions

We present a comprehensive ray tracing analysis of a novel photonic physical unclonable function (PUF) based upon the ultrafast nonlinear optical interactions in a silicon chaotic micro-cavity exploited for secure authentication and communication. The cavitys design exhibits complex chaotic behavior that ensures extreme sensitivity to the precise physical structure made unique through fabrication variances. As such, the PUFs security is partly ensured by the extreme difficultly faced in simulating a cavitys response with significant accuracy. However, general behavior from simulations can guide the design process to, for example, maximize response unpredictability and enhance interaction complexity. Although computational electrodynamic methods which solve Maxwells equations are prevalent, they have high processing costs which negate rapid design optimization. Here we show the results of a ray tracing analysis to quantify the chaotic nature of the device and examine the subsequent impact of fabrication variance. We further compare these results to finite element simulations and experimental results to examine accuracy. This computationally-efficient method can serve as a valuable tool in the development of these next-generation security devices.

Secure authentication using the ultrafast response of chaotic silicon photonic microcavities

We demonstrate a cryptographic primitive and authentication system based on the ultrafast response of reverberant integrated photonic cavities formed in silicon, which leverage the unpredictability of leaky chaotic systems.

End-fire silicon waveguide array as a platform for high power beam shaping and steering

We demonstrate a scalable array of end-firing silicon waveguides as a platform for high-speed, high-power operation beam-steering applications. We fabricate devices, culminating in 16×1 arrays with a measured central lobe FWHM of 7°±0.6°.