Content Details | NUML Online Research Repository

Title Design of tunable Fabry Perot filter for spectroscopic applications

Author(s) Muhammad Talha Rafi

Abstract Many spectroscopy applications demand tiny, durable, and portable spectrometers that are far less expensive than present solutions. As a result, micro spectrometer technology is fast evolving, and numerous research organizations are working on it. Tunable Fabry-Pérot filters (TFPF) outperform other types of devices in terms of miniaturization and optical throughput. Spectroscopy is the analysis of the relationship between matter and electromagnetic radiation as a function of the wavelength or frequency of the radiation. The optical Nano spectrometer is made up of a static FP filter array with cavities and a matched detector array, with each filter producing its own spectral filter line dependent on cavity thickness. In a FP interferometer filter, wavelength selectivity is achieved via a multiple-beam interference approach. The filter is often made up of two highly reflecting mirrors that form a resonating cavity that causes multiple-beam interference, with a single input and output port. Tunable FP filters that are tuned on all cavity spaces, giving an advantage in the size and space department of the filter. Instead of utilizing an array of filters, single filter is used. To accomplish this, analyses several materials from the COMSOL Multiphysics library to examine thin film structures, and then optimize adjusted Fabry-Pérot filters (FPF) using the best material available. The FPF core structure features three upper Distributed Bragg Reflector (DBR) mirror layers connected to three lower DBR layers. The cavity layer, made from PZT, is nestled between these layers. The upper layers are composed of SiO2 and a central layer from TiO2, while the lower layer is encapsulated by TiO2. This intricate geometric configuration is crucial for optimal performance in spectroscopic applications. The research shows fixed FP filters, with their fixed spacing between DBR layers, transmit a specific wavelength of light. They are not tunable and can only operate at the designed wavelength. Tunable filters can adjust the spacing between DBR layers, allowing them to select different wavelengths. This makes them versatile and suitable for various applications. Tunable filters are complex and require precise control systems and can have variable spectral resolution depending on the selected wavelength and adjustment mechanism. We delve into the FPF filter's response when exposed to distinct voltage Range settings. Each voltage setting corresponds to a specific mirror separation distance, which, in turn, determines the filter's transmission characteristics. At its maximum iv tuning capacity, the FPF exhibits a remarkable shift in interference fringes. This allows for the broadest range of wavelengths to either pass through or be blocked. Comprehending the voltage-dependent tunability of the TFPF, spanning from 1V to 40V, is a pivotal aspect of its adaptability and usefulness in various optical applications. Researchers and engineers, through this understanding, can harness the device's capabilities to precisely control wavelengths, thereby driving advancements in optical communication, spectroscopy, and various other optical technologies.

Type Thesis/Dissertation MS

Faculty Engineering and Computer Science

Department Engineering

Language English

Publication Date 2024-08-05

Subject

Publisher

Contributor(s)

Format

Identifier

Source

Relation

Coverage

Rights