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A study on degradation of spatial resolution in frequency-modulated continuous wave reflectometry due to nonlinear optical frequency sweep
- Source :
- Electronics and Communications in Japan (Part II: Electronics). 78:28-35
- Publication Year :
- 1995
- Publisher :
- Wiley, 1995.
-
Abstract
- The degradation of the spatial resolution in frequency-modulated continuous wave (FMCW) reflec-tometry due to the nonlinearity in the optical frequency sweep are discussed both experimentally and theoretically. The response lag in the optical frequency change of a laser diode behind the injection current change was experimentally measured, showing that there were several time constants in the optical frequency response. The interference signals in the FMCW reflectometry were theoretically calculated by taking account of the response lag. From these calculations, the beat frequency becomes low just after the turning point of the optical frequency sweep; this is due to the response lag in the optical frequency response. As a result, the spectrum of the interference signal is spread out toward the low frequency region and spatial resolution is degraded. Moreover, the spatial resolution is seriously degraded with increasing the diagnosing distance due to the nonlinearity in the optical frequency sweep. The calculated results agree well with the measured results.
- Subjects :
- Materials science
genetic structures
Laser diode
Computer Networks and Communications
business.industry
Time constant
Physics::Optics
General Physics and Astronomy
Low frequency
Interference (wave propagation)
eye diseases
Sweep frequency response analysis
law.invention
Optics
law
Modulation
Continuous wave
sense organs
Electrical and Electronic Engineering
business
Reflectometry
Subjects
Details
- ISSN :
- 15206432 and 8756663X
- Volume :
- 78
- Database :
- OpenAIRE
- Journal :
- Electronics and Communications in Japan (Part II: Electronics)
- Accession number :
- edsair.doi...........fdbec0c036a632fee1fc810bee10750c