Robust Estimation of Optical Phase Varying as a Continuous Resonant Process

TL;DR

This paper develops a robust estimation method for optical phase variations modeled as a complex resonant process, improving accuracy despite uncertainties in system parameters.

Contribution

It introduces a guaranteed cost robust filter for optical phase estimation under a resonant noise process, extending previous work to more complex models.

Findings

Robust filter achieves accurate phase estimation despite parameter uncertainties.

Demonstrates effectiveness for complex resonant noise processes.

Improves reliability of quantum optical phase measurements.

Abstract

It is well-known that adaptive homodyne estimation of continuously varying optical phase provides superior accuracy in the phase estimate as compared to adaptive or non-adaptive static estimation. However, most phase estimation schemes rely on precise knowledge of the underlying parameters of the system under measurement, and performance deteriorates significantly with changes in these parameters; hence it is desired to develop robust estimation techniques immune to such uncertainties. In related works, we have already shown how adaptive homodyne estimation can be made robust to uncertainty in an underlying parameter of the phase varying as a simplistic Ornstein-Uhlenbeck stochastic noise process. Here, we demonstrate robust phase estimation for a more complicated resonant noise process using a guaranteed cost robust filter.