Optically tunable millimeter-wave attenuator based on layered structures

• Published in: Microwave and optical technology letters Vol. 27; no. 1; pp. 9 - 13
• Main Authors: Lee, Sangil, Kuga, Yasuo, Mullen, Ruth Ann
• Format: Journal Article
• Language: English
• Published: New York John Wiley & Sons, Inc 05.10.2000
• Subjects: high-resistivity silicon; layered structure; millimeter wave; optical excitation; optically tunable attenuator
• ISSN: 0895-2477; 1098-2760
• DOI: 10.1002/1098-2760(20001005)27:1<9::AID-MOP4>3.0.CO;2-J

A new type of optically controllable, millimeter‐wave (MMW) attenuator based on high‐resistivity (high‐R) silicon (Si) wafers and a layered structure is developed. A high‐R float‐zone Si wafer is a lossless dielectric material at microwave frequency without optical excitation. When an Si wafer is optically excited, free carriers are generated, and the Si wafer becomes a lossy dielectric. This property is combined with a layered structure to develop a simple optically tunable MMW attenuator. A more than 20 dB attenuation with a 10% bandwidth of the center frequency is obtained at W‐band. The proposed structure is useful for developing low‐cost attenuators and switches in the MMW region. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 27: 9–13, 2000.