Self-Configuring Universal Linear Optical Component

TL;DR

This paper introduces a universal, self-configuring linear optical device capable of performing any linear transformation, adaptable to changing conditions without global optimization, applicable across various wave-based systems.

Contribution

It presents a progressive design method for universal linear optical components that self-configure using local feedback, eliminating the need for complex global optimization.

Findings

Device can perform any linear function or coupling.

Self-configuration adapts to component drifts and changing conditions.

Applicable to various wave systems beyond optics.

Abstract

We show how to design an optical device that can perform any linear function or coupling between inputs and outputs. This design method is progressive, requiring no global optimization. We also show how the device can configure itself progressively, avoiding design calculations and allowing the device to stabilize itself against drifts in component properties and to continually adjust itself to changing conditions. This self-configuration operates by training with the desired pairs of orthogonal input and output functions, using sets of detectors and local feedback loops to set individual optical elements within the device, with no global feedback or multiparameter optimization required. Simple mappings, such as spatial mode conversions and polarization control, can be implemented using standard planar integrated optics. In the spirit of a universal machine, we show that other linear operations, including frequency and time mappings, as well as non-reciprocal operation, are possible in principle, even if very challenging in practice, thus proving there is at least one constructive design for any conceivable linear optical component; such a universal device can also be self-configuring. This approach is general for linear waves, and could be applied to microwaves, acoustics and quantum mechanical superpositions.