Digitally enhanced heterodyne interferometry
Date
2007-11-15
Authors
Shaddock, Daniel A.
Journal Title
Journal ISSN
Volume Title
Publisher
Optical Society of America
Abstract
Combining conventional interferometry with digital modulation allows interferometric signals to be isolated
based on their delay. This isolation capability can be exploited in two ways. First, it can improve measurement
sensitivity by reducing contamination by spurious interference. Second, it allows multiple optical components
to be measured using a single metrology system. Digitally enhanced interferometry employs a pseudorandom
noise (PRN) code phase modulated onto the light source. Individual reflections are isolated based
on their respective delays by demodulation with the PRN code with a matching delay. The properties of the
PRN code determine the degree of isolation while preserving the full interferometric sensitivity determined
by the optical wavelength. Analysis and simulation indicate that errors caused by spurious interference can
be reduced by a factor inversely proportional to the PRN code length.
Description
Keywords
interferometry, digital, modulation, interferometric, signal, isolation, measurement, sensitivity, contamination, metrology, single, pseudorandom noise (PRN)
Citation
Collections
Source
Optics Letters
Type
Journal article
Book Title
Entity type
Access Statement
Open Access