Wavelength-Scale Photonic Signal Processing Components

Purdue University, West Lafayette IN

Investigators

Abstract

0524442 Webb Terahertz and optical signal processing elements will be studied to facilitate new functionalities and integrated circuit realizations critical for high capacity communication and signal processing. The fundamental concepts to be employed are the irregular waveguide field transformation structures developed by the Webb group and the THz characterization techniques pioneered by the Nelson group. Irregular terahertz field transformation structures that will achieve wavelength division multiplexing and phase shifting functions will be designed, fabricated and tested. This work will demonstrate both spatial and spectral control of the scattered fields in the terahertz domain for the first time. Implementation will utilize a polaritonics signal processing platform in which arbitrarily specified terahertz signal generation, signal manipulation, signal propagation through integrated functional elements, and signal readout are all conducted optically, using commonly available electrooptic, ferroelectric crystals. The proposed devices will be fabricated using femtosecond laser machining. Silicon-on-insulator waveguide structures, including mode control and power splitting components, will be designed for operation at a wavelength of 1.55 micron. Irregular field transformation structures offer dramatic improvements in virtually all terahertz and optical signal processing elements, from control of source fields to more efficient detectors, and in the quest for terahertz and optical integrated circuits. The proposed work will have broader impact in bringing this technology to research and development community and ultimately the public. The synthesis software, including the forward and inverse solvers, will be made available on a Purdue web site, and this will be indicated in journal and conference papers published. Two Ph.D. students, one each at Purdue and MIT, will be supported in part by this award, and the work will constitute part of their theses. At MIT, the project will dovetail with parallel developments in polaritonics technology, including coherent control over signal generation and direct imaging of signal propagation, that will further accelerate its use in practical signal processing applications.