The Standard Quantum Limit of Coherent Beam Combining

TL;DR

This paper calculates the quantum noise limit for coherent beam combining, demonstrating that it approaches the shot noise limit with many inputs, and introduces a Fourier-based scheme compatible with integrated optics.

Contribution

It provides the first quantum mechanical noise limit analysis for coherent beam combining and proposes a Fourier-based scheme suitable for integrated optics.

Findings

Approaches the shot noise limit with many input beams

Compatible with integrated optics via Fourier transformation

First quantum noise limit calculation for this scheme

Abstract

Coherent beam combining refers to the process of generating a bright output beam by merging independent input beams with locked relative phases. We report the first quantum mechanical noise limit calculations for coherent beam combining and compare our results to quantum-limited amplification. Our coherent beam combining scheme is based on an optical Fourier transformation which renders the scheme compatible with integrated optics. The scheme can be layed out for an arbitrary number of input beams and approaches the shot noise limit for a large number of inputs.