Date of Award
5-2024
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Electrical and Computer Engineering (Holcomb Dept. of)
Committee Chair/Advisor
Hai Xiao
Committee Member
Fei Peng
Committee Member
Tao Wei
Committee Member
Lianfeng Zhao
Abstract
In modern photonics, combining microwave techniques with optical measurements has introduced a novel research direction. This study introduces a novel Microwave Photonics Wavelength Measurement System (MP-WMS), integrating microwave photonics with fiber chromatic dispersion to achieve direct wavelength measurement. Utilizing cost effective single mode optical fibers as dispersion devices, this system employs chromatic dispersion to convert optical frequency domain measurements into microwave time domain measurements. We established a mathematical model to describe how different wavelengths are detected, enhancing the system's effectiveness. The MP-WMS system offers an affordable solution with high resolution. In the experiment, we used a 35km long SM-28 single-mode fiber as the dispersion device and obtained a resolution of 1pm. The resolution can be improved by extending the fiber length or employing fibers with higher dispersion coefficients. It is characterized by good stability and the ability to measure light intensity, although it is unsuitable for broadband light with nearly uniform optical intensity across the spectrum. We further explored the system’s capabilities by deploying a setup to demodulate signals from five cascaded fiber Bragg gratings (FBG). The microwave-modulated optical signals are amplified and undergo dispersion, and the resultant microwave information is extracted by a high-speed photodetector. The shifts in Bragg wavelengths, determined using a vector network analyzer and inverse Fourier transform, verify the system’s precision. Our experiments confirmed that the MP-WMS system can effectively distinguish various Bragg wavelengths in the time domain and accurately measure spectra composed of multiple narrowband lights. In summary, our research not only presents a pioneering method for direct wavelength determination but also extends its applications into the realm of Cascade FBGs demodulation. This work represents a significant advancement in the convergence of microwave and optical technologies, offering a wealth of opportunities for future research and practical applications.
Recommended Citation
Wu, Yongji, "Optical Wavelength Measurement Based on Microwave-Photonics and Fiber Dispersion" (2024). All Dissertations. 3555.
https://open.clemson.edu/all_dissertations/3555