Ultra High Capacity WDM Device Based on Novel Phased Array Design and Laser Fabrication of 3-D Optical Waveguides

Purdue University, West Lafayette IN

Investigators

Abstract

This proposal was submitted and funded in response to solicitation NSF 03-537 High Speed Optical Communications and Networks. Technological interest in dense wavelength division multiplexing (DWDM) systems is fast increasing since DWDM systems offer a very large transmission capacity and new novel network architectures. Major components in DWDM systems are the wavelength multiplexers and demultiplexers, such as arrayed waveguide grating (AWG). However, the capacity of current AWG devices is limited in terms of the number of channels that can be manufactured in a given volume because of their 2-D geometry using lithography techniques as well as algorithms used involving regular sampling and limited use of phase modulation. The proposed work will design and manufacture a new generation, 3-D AWGs by combining novel design methodologies of AWGs and novel laser-based manufacturing techniques. A major bottleneck in phased-array types of devices used in DWDM is the free spectral range (FSR) allowed. We will develop a novel dense wavelength division multiplexing (DWDM) system in which there is only one effective order per wavelength so that the number of channels or images corresponding to different wavelengths is not restricted due to FSR. The method involves irregular sampling of zero-crossings of phase with linear and/or spherical reference waves. This method also allows the design of 3-D systems with a very large increase in the number of AWG channels. We will implement regularly and irregularly sampled AWGs in the design of 3-D DWDM systems using the femtosecond laser manufacturing technology. By focusing a femtosecond laser beam inside a dielectric media to increase the index of refraction at the laser focal point, and with the aid of 3-D computer aided design and manufacturing, truly 3-D waveguides, which are essential parts in the 3-D AWG devices can be fabricated. In order to optimize against various error sources and to incorporate multifunctional system behavior, we will also incorporate diffractive optical elements optimized with iterative minimum mean-squared error methods and a closed loop manufacturing technique. The success of the proposed work will have very high potential for progress in multispectral communications, networking and computing. Topics such as ultra high capacity WDM will be more significant in the upcoming progress for communications of parts in complex micro/nano systems, and the demand for more and more number of wavelengths will increase. Progress in 3D will open up completely new possibilities and bring along tremendous increase in capacity, and totally new design techniques. The project is being jointly sponsored by the Thermal Transport and Thermal Processing Program of the Chemical and Transport Systems Division and the Materials Processing and Manufacturing Program of the Design, Manufacturing and Industrial Innovation Division.