EXPERIMENT NO. 7
FIBER-OPTIC MACH-ZEHNDER INTERFEROMETERS
To introduce the basic principle of optical interferometry, to illustrate the use of
interferometers in engineering applications and to introduce the use of single-mode
optical fibers and fiber couplers in interferometric sensors.
Fiber Optic Sensors: An Introduction for Engineers and Scientists
Wiley & Sons, Inc., (1991), Chapter 10.
A. Dandridge and A. D. Kersey, "Overview of Mach-Zehnder Sensor
Technology and Applications," Proceedings, SPIE Vol. 985,
Fiber Optic and Laser
(1988), The International Society for Optical Engineering,
3. Several papers in
Optical Fiber Sensors
, 1988 Technical Digest
Series, Vol. 2, Part 1, Interferometric Techniques, pp. 40-58.
An Introduction to Interferometry
, Wiley and Sons, Inc., second
edition, (1973), Chapters 8 and 9.
The Mach-Zehnder interferometer (attached).
PZT Primer (attached)
Read Ref. [5, 6] before proceeding further with the experiment.
Arrange a laser, microscope objectives, fiber-optic positioners (FOP), fiber
couplers, a PZT cylinder, a beam splitter, etc. as sho
wn in Figure 1. Don’t
bump or break the fiber tips.
In Steps 1 through 6, no voltage is applied to the
Use microscope objectives to couple light into each input end of the fiber
The input ends (port 1 and 2) of the fiber coupler are on the side of the
fiber coupler that contains the PZT cylinder.
With no light into the other input
end, adjust each fiber optic positioner (FOP) separately until a bright beam
emerges from the output ends of the fiber coupler.
Use a power meter to
monitor one of the outputs (port 3 and 4) and adjust
each input FOP for
maximum coupling into each fiber.