Validation of separated source frequency delivery for a fiber-coupled heterodyne displacement interferometer

Validation of separated source frequency delivery for a fiber-coupled heterodyne displacement interferometer

Meskers, A.J.H.
Spronck, J.W.
Munnig Schmidt, R.H.

Mechanical, Maritime and Materials Engineering

Precision and Microsystems Engineering

2014-07-31

The use of optical fibers presents several advantages with respect to free-space optical transport regarding sourcefrequency delivery to individual heterodyne interferometers. Unfortunately, fiber delivery to individual coaxial heterodyne interferometers leads to an increase of (periodic) nonlinearity in the measurement, because transporting coaxial frequencies through one optical fiber leads to frequency mixing. Coaxial beams thus require delivery via free-space transportation methods. In contrast, the heterodyne interferometer concept discussed in this Letter is based on separated source frequencies, which allow for fiber delivery without additional nonlinearity. This investigation analyzes the influence of external disturbances acting on the two fibers during delivery, causing asymmetry in phase between the two fibers (first-order effect), and irradiance fluctuations (second-order effect). Experiments using electro-optic phase modulation and acousto-optic irradiance modulation confirmed that the interferometerconcept can measure with sub-nanometer uncertainty using fiber delivered source frequencies, enabling fully fiber-coupled heterodyne displacement interferometers.

instrumentation, measurement, and metrology
interferometry
metrology
optical design of instruments
optical systems
phase measurement

http://resolver.tudelft.nl/uuid:2e291ac6-fda9-4ce6-8440-ff70df147c7f

Optical Society of America

0146-9592

http://www.opticsinfobase.org/ol/abstract.cfm?uri=ol-39-15-4603

Optics Letters, 39 (15), 2014

Institutional Repository

journal article

© 2014 Optical Society of America