Modular architecture of large-scale optical interferometers for sparsely populated input

TL;DR

This paper introduces a modular optical interferometer architecture that enables large-scale transformations by splitting the process into scattering and mixing stages, making fabrication more feasible with existing photonics technology.

Contribution

The work proposes a novel two-stage modular architecture for large-scale optical interferometers, facilitating their construction with low-depth circuits and minimal interconnection complexity.

Findings

Allows realization of large transformations with simpler circuits

Reduces fabrication complexity for large-scale interferometers

Offers a viable approach despite non-universality

Abstract

Today, the realization of large optical interferometer schemes is necessary for many sophisticated information processing algorithms. In this work, we propose a modular interferometer architecture possible when the number of input channels of a transformation populated with signals is much lesser than the total number of its channels. The underlying idea is to split the transformation into two stages. In the first stage, the signals undergo scattering among multiple channels of separate optical schemes, while in the second stage, they are made to interfere with each other, thus, we call it the mixing stage. This way, large-scale transformations that technically challenging to fabricate even by means of the mature integrated photonics technology, can be realized using multiple low-depth optical circuits, yet at the expense of single interconnection between the scattering and mixing parts of the interferometer. Although non-universal, as witnessed by the parameters set to define the interferometer, the architecture provides a viable approach to construction of large-scale interferometers.