University of Delaware - College of Engineering
ELECTRICAL & COMPUTER ENGINEERING

Research

Photonics & Electromagnetics

Antenna Coupled Nano-Photonic Waveguides for MMW FPAs

Dennis Prather

Millimeter waves (MMWs) exist in the electromagnetic spectrum with wavelengths in the range of 1 cm to 1 mm. As such, they have frequencies that span 30-300 GHz, which is located just between the microwave and infrared portions of the spectrum. Because of their unique ability to penetrate fog, dust, smoke, blowing sand, and light rain, MMW imaging systems are very attractive for many applications. However, their use to date has been limited due to the lack of suitable technologies that meet or exceed specific criteria's such as resolution, sensitivity, and cost. To overcome these limitations we are pursuing a novel approach to develop a new type of MMW focal plane array, namely a nano-photonic approach. This approach does not require expensive high-speed electronic detection and read out circuits and its theoretical limitation in sensitivity is set by the fundamental contribution of shot noise. In comparison to competing approaches, such as monolithic-microwave integrated circuits (MMICs) where filtering, amplification, and mixing operations at frequencies approaching 100 GHz are performed using high speed electronics, our approach is significantly more simple in that it is based on the planar and monolithic integration of photonic devices. In addition, approaches based on antenna-coupled microbolometers have proven to have noise equivalent powers NEP in the 10's to 100's of pico-watts, which in many cases does not satisfy the sensitivity requirements in many applications. In contrast, photonic approaches developed in our lab have yielded NEP's as low as 450 fW/Hz , which is sufficient to resolve passively emitted radiation from terrestrial objects with temperature resolution approaching 1ÂșC without using cooling or low-noise amplifiers.

Recent publications

C. A. Schuetz, J. Murakowski, G. J. Schneider and D. W. Prather, "Radiometric millimeter-wave detection via optical upconversion and carrier suppression," IEEE Transactions on Microwave Theory and Techniques, 53, 1732-1738, 2005.

D. W. Prather, Shouyuan Shi, Tim Hwang, Rownak Shireen, ZhaoLin Lu, and Christopher Schuetz, "Design and Fabrication of Millimeter Wave Photonic Modulators", IEEE Antenna & Propagation Society Symposium, July 3-8, Washington D.C. 2005

C. A. Schuetz, C. Huang, R. Shireen, T. H. Hwang, G. J. Schneider, J. A. Murakowski, D. W. Prather," Electro-optic modulator optimization for optically-based passive millimeter-wave detection, " Proc. SPIE Vol. 6120, Terahertz and Gigahertz electronics and Photonics V, p. 103-111, Jan 2006.


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