This paper reports a spatially continuous distributed fiber optic sensing technique using optical carrier based microwave interferometry (OCMI), in which many optical interferometers with the same or different optical path differences are interrogated in the microwave domain and their locations can be unambiguously determined. The concept is demonstrated using cascaded weak optical reflectors along a single optical fiber, where any two arbitrary reflectors are paired to define a low-finesse Fabry-Perot interferometer. While spatially continuous (i.e., no dark zone), fully distributed strain measurement was used as an example to demonstrate the capability, the proposed concept may also be implemented on other types of waveguide or free-space interferometers and used for distributed measurement of various physical, chemical and biological quantities.


Electrical and Computer Engineering


National Energy Technology Laboratory (U.S.)
National Science Foundation (U.S.)


The authors acknowledge funding supports from Department of Energy, National Energy Technology Laboratory, under Contract Number DE-FE0012272, and National Science Foundation CMMI-1359716.

Keywords and Phrases

Interferometers; Optical fibers; Reflection; Fabry-Perot interferometers; Fiber optics; Interferometers; Internet protocols; Optical fibers; Reflection, Chemical and biologicals; Distributed measurements; Distributed strain measurement; Fiber-optic sensing; Microwave interferometries; Optical interferometer; Optical path difference; Single optical fibers, Internet protocols; Interferometry

International Standard Serial Number (ISSN)


Document Type

Article - Journal

Document Version

Final Version

File Type





© 2014 Optical Society of America, All rights reserved.

Publication Date

01 Jul 2014