*1.1.3.3 The Mach-Zehnder interferometer (MZI)*

The light beam is split into two pieces that go through the reference and detecting arms, respectively, before being recombined in this arrangement. The optical channels are only crossed once, unlike in the Michelson interferometer. Two photodetectors are installed in each of the interferometer's outputs. The phase shift caused by variations in the sensing arm caused by temperature, strain, or refractive index changes, among other things, can be quantified using the intensities detected by both detectors. This interferometer can be implemented in integrated optics, which protects the device, reduces its size, and allows it to be used for other purposes like biosensing [51, 52].
