Figure 11. Shematic diagrams of (a) Michelson, and (b)
Mach-Zehnder interferometers.
There are similarities and differences between the
Michelson and Mach–Zehnder interferometers. In terms of
similarities, the Michelson is often considered to be folded
Mach–Zehnder, and vice versa. Michelson configuration
requires only one optical fiber coupler. Because the light
passes both through the sensing and reference fibers
twice, the optical phase shift per unit length of fiber is
doubled. Thus, the Michelson can intrinsically have better
sensitivity. Another clear advantage of the Michelson is
that the sensor can be interrogated with only a single fiber
between the source-detector module and the sensor.
However, a good-quality reflection mirror is required for the
Michelson interferometer [10].