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Proceedings Paper

A robust design and fabrication of micromachined electro-absorptive optical modulator for 3D imaging
Author(s): Yong-Hwa Park; Yong-Chul Cho; Jang-Woo You; Chang-Young Park; Heesun Yoon; Sang-Hun Lee; Byung Hoon Na; Gun Wu Ju; Hee Ju Choi; Yong Tak Lee
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Paper Abstract

A time-of-flight (TOF) based three dimensional (3D) image capturing system and its enhanced optical modulating device are presented. The 3D image capturing system includes 850nm IR emitter (typically compact Laser diodes) and high speed image modulator, so called optical shutter. The optical shutter consists of multi-layered optical resonance cavity and electro-absorptive layers. The optical shutter is a solid-state controllable filter which modulates the IR image to extract the phase delay due to TOF of the emitting IR light. This presentation especially addresses robustness issues and solutions when operated under practical environments such as ambient temperature variation and existence of strong ambient light (e.g. outdoors). The wavelength of laser diode varies substantially depending on the ambient temperature, which degrades the modulation efficiency. To get a robust operation, the bandwidth of transmittance of the optical shutter is drastically improved with a novel coupled Fabry-Perot resonance cavity design to come up with the wavelength variation of the laser diode. Also, to suppress the interference of solar irradiance to IR source signal, a novel driving scheme is applied, in which IR light and optical shutter modulation duties are timely localized, i. e. ‘bursted’. Suggested novel optical shutter design and burst driving scheme enable capturing of a full HD resolution of depth image under the realistic usage environments, which so far tackle the commercialization of TOF cameras. Design, fabrication, and evaluation of the optical shutter; and, 3D capturing system prototype, image test results are presented.

Paper Details

Date Published: 7 March 2014
PDF: 14 pages
Proc. SPIE 8977, MOEMS and Miniaturized Systems XIII, 89770C (7 March 2014); doi: 10.1117/12.2039054
Show Author Affiliations
Yong-Hwa Park, Samsung Advanced Institute of Technology (Korea, Republic of)
Yong-Chul Cho, Samsung Advanced Institute of Technology (Korea, Republic of)
Jang-Woo You, Samsung Advanced Institute of Technology (Korea, Republic of)
Chang-Young Park, Samsung Advanced Institute of Technology (Korea, Republic of)
Heesun Yoon, Samsung Advanced Institute of Technology (Korea, Republic of)
Sang-Hun Lee, Samsung Advanced Institute of Technology (Korea, Republic of)
Byung Hoon Na, Gwangju Institute of Science and Technology (Korea, Republic of)
Gun Wu Ju, Gwangju Institute of Science and Technology (Korea, Republic of)
Hee Ju Choi, Gwangju Institute of Science and Technology (Korea, Republic of)
Yong Tak Lee, Gwangju Institute of Science and Technology (Korea, Republic of)


Published in SPIE Proceedings Vol. 8977:
MOEMS and Miniaturized Systems XIII
Wibool Piyawattanametha; Yong-Hwa Park, Editor(s)

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