Frequency Division Multiplexing of Interferometric Sensor Arrays
Abstract
This report demonstrates the multiplexing of fiber optic interferometric sensors using a CW phase generated carrier technique. The technique employs modulated diode laser sources at different carrier frequencies, near balanced interferometers (approx. 4 cm path difference) and phase generated carrier demultiplexing demodulation. This approach leads to a simple all-passive sensor array which has intrinsically low crosstalk. The system is analyzed in terms of shot noise performance and crosstalk. An experimental all optical implementation of a four sensor array was demonstrated; both the single sensor and multisensor arrays were limited by the laser phase noise to a sensitivity of approx. 18 micro rad/(sq. rt Hz). Crosstalk between individual channels was better than -60 dB. In the absence of laser phase/noise the demodulator/demultiplexer demonstrated approx. 2 microrad performance with both single senso and four element array operation, and 4 microrad performance with 8 elements in operation. Keywords: Fiber optic sensors; Optical detectors; Frequency division multiplexing.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 03, 1989
- Accession Number
- ADA208448
Entities
People
- A. B. Tveten
- A. D. Kersey
- A. Dandridge
- A. M. Yurek
- E. C. Mcgarry
Organizations
- United States Naval Research Laboratory