Digital spatial wavelength domain multiplexing (DSWDM) using a prism-grating-prism (PGP) and a CMOS imager: implementation and initial testing

Martin B. Christiansen; Steve Chen; Christopher S. Baldwin; John B. Niemczuk; Jason S. Kiddy; Peter C. Chen; Harri K. Kopola; Mauri Aikio; Pekka Suopajarvi; Steven G. Buckley

doi:10.1117/12.435513

6 August 2001 Digital spatial wavelength domain multiplexing (DSWDM) using a prism-grating-prism (PGP) and a CMOS imager: implementation and initial testing

Martin B. Christiansen, Steve Chen, Christopher S. Baldwin, John B. Niemczuk, Jason S. Kiddy, Peter C. Chen, Harri K. Kopola, Mauri Aikio, Pekka Suopajarvi, Steven G. Buckley

Author Affiliations +

Proceedings Volume 4328, Smart Structures and Materials 2001: Sensory Phenomena and Measurement Instrumentation for Smart Structures and Materials; (2001) https://doi.org/10.1117/12.435513
Event: SPIE's 8th Annual International Symposium on Smart Structures and Materials, 2001, Newport Beach, CA, United States

Abstract

A CMOS imager-based spectrometer is used to interrogate a network containing a large number of Bragg grating sensors on multiple fibers as part of a proprietary structural health monitoring system. The spectrometer uses a Prism-Grating-Prism (PGP) to spectrally separate serially multiplexed Bragg reflections on a single fiber. As a result, each Bragg grating produces a discrete spot on the CMOS imager that shifts horizontally as the Bragg grating experiences changes in strain or temperature. The reflected wavelength of the Bragg grating can be determined by finding the center of the spot produced. The use of a random addressing CMOS imager enables a flexible sampling rate. Some fibers can be interrogated at a high sampling rate while others can be interrogated at a lower sampling rate. However, the use of a CMOS camera brings several specific problems in terms of signal processing. These include a logarithmic pixel response, a low signal-to-noise ratio, the long pixel time constant, obtaining sufficient process priority for the control program, and proper selection of the window of interest. In this paper we investigate computer algorithms and hardware solutions to address these problems. We also present experimental data to validate these solutions including calibration data and initial field-testing data with 24 sensors on 4 fibers.

Citation Download Citation

Martin B. Christiansen, Steve Chen, Christopher S. Baldwin, John B. Niemczuk, Jason S. Kiddy, Peter C. Chen, Harri K. Kopola, Mauri Aikio, Pekka Suopajarvi, and Steven G. Buckley "Digital spatial wavelength domain multiplexing (DSWDM) using a prism-grating-prism (PGP) and a CMOS imager: implementation and initial testing", Proc. SPIE 4328, Smart Structures and Materials 2001: Sensory Phenomena and Measurement Instrumentation for Smart Structures and Materials, (6 August 2001); https://doi.org/10.1117/12.435513

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available