Autocorrective interferometers for photonic integrated circuits

TL;DR

This paper introduces autocorrective interferometers for photonic integrated circuits, leveraging Bloch sphere representation for design, and reviews recent practical implementations in silicon photonics.

Contribution

It presents a novel analytical design approach for autocorrective interferometers using Bloch sphere representation, enhancing robustness and simplifying fabrication tolerance considerations.

Findings

Bloch sphere provides deep physical insight into device operation.

Analytical formulas enable straightforward design of broadband splitters.

Recent implementations demonstrate practical viability in silicon photonics.

Abstract

Extensive literature has shown that finite impulse response (FIR) interferometers can be engineered to be insensitive under variations of different physical parameters, e.g., to ensure flat-top response and/or tolerance to fabrication errors. In this context, I will show how the Bloch sphere representation can be a very powerful design tool providing superior physical insight into the working principle of autocorrective devices like broadband 50:50 splitters or flat-top interleavers, that can be therefore designed through simple analytical formulas. I will eventually review the recent progress in practical implementation of the autocorrective designs in the micron-scale silicon photonics platform of VTT.