Quantum Modelling of Electro-Optic Modulators

TL;DR

This paper reviews the quantum scattering theory of electro-optic modulators, highlighting their operation under quantum conditions and exploring their applications in quantum communication and photonic systems.

Contribution

It provides a comprehensive quantum model of electro-optic modulators, including a tutorial on their application in quantum information processing.

Findings

Quantum models of phase and amplitude modulators are developed.

Applications include quantum key distribution and single-photon measurements.

The paper demonstrates how classical devices operate under quantum regimes.

Abstract

Many components that are employed in quantum information and communication systems are well known photonic devices encountered in standard optical fiber communication systems, such as optical beamsplitters, waveguide couplers and junctions, electro-optic modulators and optical fiber links. The use of these photonic devices is becoming increasingly important especially in the context of their possible integration either in a specifically designed system or in an already deployed end-to-end fiber link. Whereas the behavior of these devices is well known under the classical regime, in some cases their operation under quantum conditions is less well understood. This paper reviews the salient features of the quantum scattering theory describing both the operation of the electro-optic phase and amplitude modulators in discrete and continuous-mode formalisms. This subject is timely and of importance in light of the increasing utilization of these devices in a variety of systems, including quantum key distribution and single-photon wavepacket measurement and conformation. In addition, the paper includes a tutorial development of the use of these models in selected but yet important applications, such as single and multi-tone modulation of photons, two-photon interference with phase-modulated light or the description of amplitude modulation as a quantum operation.