Stark Tuning and Charge State Control in Individual Telecom C-Band Quantum Dots

TL;DR

This paper demonstrates Stark tuning and charge state control of individual telecom C-band quantum dots, enabling their use in scalable, fiber-compatible quantum photonic devices with potential for entangled photon generation.

Contribution

We present the first combined electrical Stark tuning and charge control of InAs/InP quantum dots in the telecom C-band, including fine structure splitting tuning for entangled photon emission.

Findings

Tuning range exceeds 2.4 nm via Stark effect

Controlled charge occupancy of quantum dots achieved

Electrical tuning of fine structure splitting demonstrated

Abstract

Telecom wavelength quantum dots (QDs) are emerging as a promising solution for generating deterministic single photons compatible with existing fiber optic infrastructure. Emission in the low loss C band minimizes transmission losses, making them ideal for long distance quantum communication. In this work, we present a demonstration of both Stark tuning and charge state control of individual InAs/InP QDs operating within the telecom C-band. These QDs are grown by droplet epitaxy and embedded in an InP based n++-i-n+ heterostructure fabricated using MOVPE. The gated architecture enables the tuning of emission energy via the quantum confined Stark effect, with a tuning range exceeding 2.4 nm. It also allows for control over the QD charge occupancy, enabling access to multiple discrete excitonic states. Electrical tuning of the fine structure splitting is further demonstrated, opening a route to entangled photon pair generation at telecom wavelengths. The single photon character is confirmed via second order correlation measurements. These advances enable QDs to be tuned into resonance with other systems, such as cavity modes and emitters, marking a critical step toward scalable, fiber compatible quantum photonic devices.