Design Scheme for Mach-Zehnder Interferometric CWDM Wavelength Splitters/Combiners

TL;DR

This paper presents an analytical design method for Mach-Zehnder interferometric CWDM wavelength splitters/combiners that accounts for wavelength-dependent couplers, enabling more accurate and versatile device design.

Contribution

It introduces an analytical approach incorporating wavelength dependence into the design of Mach-Zehnder interferometric splitters, expanding the design possibilities.

Findings

Derived analytical formulas for wavelength-dependent Mach-Zehnder structures

Extended geometrical representation to broader class of filters

Provided design guidelines for flattened wavelength splitters

Abstract

We propose an analytical approach to design flattened wavelength splitters with cascaded Mach-Zehnder interferometers when wavelength dependence of the directional couplers cannot be neglected. We start from a geometrical representation of the action of a doubly point symmetrical filter, assuming no wavelength dependence of the couplers. Next we derive the analytical formulas behind its working principle and we extend them to the wavelength dependent case. We also show how the geometrical representation allows to broaden the class of working structures.