Signal-to-Noise Ratio of Microwave Photonic Filter With an Interferometric Structure Based on an Incoherent Broadband Optical Source

TL;DR

This paper analyzes the signal-to-noise ratio of a microwave photonic filter with an interferometric structure using an incoherent broadband optical source, highlighting the factors affecting SNR and verifying the theory experimentally.

Contribution

It provides a comprehensive theoretical and experimental analysis of SNR in such filters, considering the effects of various parameters on performance.

Findings

SNR depends on passband center frequency, modulation index, chromatic dispersion, and IBOS shape.

Experimental results align well with theoretical predictions.

The study offers guidance for designing microwave photonic filters with improved SNR.

Abstract

A comprehensive investigation of the signal-to-noise ratio (SNR) of the microwave photonic filter (MPF) with an interferometric structure based on an incoherent broadband optical source (IBOS) is presented from the time and frequency domains, respectively. The interferometric structure and the IBOS in the MPF result in a beneficial single-bandpass radiofrequency (RF) response. However, the IBOS adds a relatively large noise to the filtered RF signal. Therefore, the analysis of the SNR is of great importance for the design of this kind of MPFs. Theoretical analysis shows that the SNR is a function of the center frequency of the passband, the modulation index, the chromatic dispersion, and the shape of the IBOS. An experiment is performed to verify the theory, and experimental results agree well with the theoretical calculation.