End-coupled optical waveguide MEMS devices in the indium phosphide material system

• Published in: Journal of micromechanics and microengineering 2006-04, Vol.16 (4), p.832-842
• Main Authors: Pruessner, Marcel W, Siwak, Nathan, Amarnath, Kuldeep, Kanakaraju, S, Chuang, Wen-Hsien, Ghodssi, Reza
• Format: Article
• Language: English
• Subjects: Applied sciences; Electronics; Exact sciences and technology; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Mechanical engineering. Machine design; Mechanical instruments, equipment and techniques; Microelectronic fabrication (materials and surfaces technology); Micromechanical devices and systems; Physics; Precision engineering, watch making; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
• ISSN: 0960-1317; 1361-6439
• DOI: 10.1088/0960-1317/16/4/021

We demonstrate electrostatically actuated end-coupled optical waveguide devices in the indium phosphide (InP) material system. The design of a suitable layer structure and fabrication process for actuated InP-based waveguide micro-electro-mechanical systems (MEMS) is reviewed. Critical issues for optical design, such as coupling losses, are discussed and their effect on device performance is evaluated. Several end-coupled waveguide devices are demonstrated, including 1 X 2 optical switches and resonant sensors with integrated optical readout. The 1 X 2 optical switches exhibit low-voltage operation ( < 7 V), low crosstalk (-26 dB), reasonable loss (3.2 dB) and switching speed suitable for network restoration applications (140 mus, 2 ms settling time). Experimental characterization of the integrated cantilever waveguide resonant sensors shows high repeatability and accuracy, with a standard deviation as low as sigma = 50 Hz (0.027%) for fresonant = 184.969 kHz. By performing focused-ion beam (FIB) milling on a sensor, a mass sensitivity of Deltam/Deltaf = 5.3 X 10-15 g Hz-1 was measured, which is competitive with other sensors. Resonant frequencies as high as f = 1.061 MHz (Qeffective = 159.7) have been measured in air with calculated sensitivity Deltam/Deltaf = 1.1 X 10-16 g Hz-1. Electrostatic tuning of the resonator sensors was also examined. The prospect of developing InP MEMS devices monolithically integrated with active optical components (lasers, LEDs, photodetectors) is discussed.