Diversity of photonic differentiators based on flexible demodulation of phase signals

TL;DR

This paper introduces a versatile photonic differentiation scheme based on phase demodulation with cascaded filters, demonstrating multiple output forms and potential applications in optical waveform processing.

Contribution

The paper presents a novel multifunctional photonic differentiation method utilizing phase demodulation and cascaded filters, with experimental validation of diverse differentiation outputs.

Findings

Achieved less than 7% deviation in differentiator waveforms

Demonstrated first and second order field differentiation

Showcased applications in ultra-wideband pulse generation

Abstract

We theoretically prove a multifunctional photonic differentiation (DIFF) scheme based on phase demodulation using two cascaded linear filters. The photonic DIFF has a diversity of output forms, such as 1st order intensity DIFF, 1st order field DIFF and its inversion, 2nd order field DIFF, dependent on the relative shift between the optical carrier and the filter's resonant notches. As a proof, we also experimentally demonstrate the DIFF diversity using a phase modulator and two delay interferometers (DIs). The calculated average deviation is less than 7% for all DIFF waveforms. Our schemes show the advantages of flexible DIFF functions and forms, which may have different optical applications. For example, high order field differentiators can be used to generate complex temporal waveforms. And intensity differentiators are useful for ultra-wideband pulse generation.