The Mach-Zehnder Interferometer Essay

Mach-Zehnder Interferometer
Maanasa Mohanambal Sathianarayanan
Department of Electrical and Computer Engineering
University of Houston, TX, USA
PSID 1440583 Email msmaanasa@uh.edu
Abstract - The Mach-Zehnder Interferometer is a photonic integrated device that is used to determine the phase shift in the collimated beams by amplitude division by using beam splitters. This paper gives insights about the framework which coordinates the phase constants and amplitude. Its working, applications and advantages of using the device establishes a strong effect on its wide spectrum of applications.
Keywords Interferometer, Photonic Integrated Circuit, Mach-Zehnder Interferometer
I INTRODUCTION
A device that integrates at least two optical functions for the optical signals in the visible spectrum or near infrared on a single chip is known as the Photonic Integrated Circuit (PIC). Figure 1 shows Multiplexers, De- multiplexers, Waveguides, Modulators, Optical Amplifiers, lasers and various such devices can be integrated onto the same chip. Mach-Zehnder Interferometer is one of Photonic Integrated Circuit devices. The interferometer is a simple device verifying interference by amplitude division.
The Mach-Zehnder Interferometer is used where the collimated beams are analyzed to find their phase shift by using two beam splitters. It is a single input dual output device which can be incorporated to devices like photodetectors. The device uses a principle of having a path traversed only once unlike the Michelson Interferometer where there occurs multiple traversals.
Figure 1. Active devices Red. Passive Devices Blue. Electronic Devices Green. Mixed Devices Purple.
The Mach-Zehnder Interferometer is predominantly used to study quantum mechanics as it shows clear path choice problems.
II WORKING
The Mach-Zehnder Interferometer examines the phase nature of light. The light is split using semi reflecting (dielectric or metal coated) mirrors. In this Interferometer, the light is transmitted from a single source onto a half silvered mirror which reflects 50% of the light and transmits the other 50% of the light. The Figure 2 shows the exact setup of the device. Usually, the upper beam is reflected and the lower beam is transmitted. These hit a fully silvered mirror which initiates recombination through another half silvered mirror. Depending on the phase shifts and refractive indices, the output is seen in only one end of the two outputs or is split in both. When the incident light is reflected by the silvered plane, there occurs a phase shift of 180 in one direction and when the light is reflected by the other plane, there occurs no change in phase. This occurs due to the difference in the refractive indices. When the output beams have same phase shifts, there occurs a constructive interference.
Figure 2 Mach-Zehnder Interferometer
The path length difference between the mirrors can be adjusted. The misaligned setup produces fringes on the output. The variations in the path length affects the interference patterns but not the power distribution of the outputs.[]
III RESOLUTION OF THE PROBLEM
The major issue in this Mach-Zehnder Interferometer is that it is unclear when the photon approaches the beam splitter from behind.[]