Fiber-pigtailing quantum-dot cavity-enhanced light emitting diodes

TL;DR

This paper presents a room-temperature, fiber-coupled quantum dot cavity LED with high coupling efficiency, demonstrating pulsed operation and low-temperature functionality, advancing practical quantum light sources for quantum information.

Contribution

A novel room-temperature fiber-coupling technique for quantum dot cavity LEDs with high efficiency and permanent attachment, suitable for quantum information applications.

Findings

Coupling efficiency of ~46% between cavity and fiber.

Successful pulsed operation at over 200 MHz.

Device operates down to 77 K temperature.

Abstract

We report on a process for the fiber-coupling of electrically driven cavity-enhanced quantum dot light emitting devices. The developed technique allows for the direct and permanent coupling of p-i-n-doped quantum dot micropillar cavities to single-mode optical fibers. The coupling process, fully carried out at room temperature, involves a spatial scanning technique, where the fiber facet is positioned relative to a device with a diameter of 2 $\mu$m using the fiber-coupled electroluminescence of the cavity emission as a feedback parameter. Subsequent gluing and UV curing enables a rigid and permanent coupling between micropillar and fiber core. Comparing our experimental results with finite element method simulations indicates a cavity-to-fiber mode-coupling efficiency of ~46%. Furthermore, we demonstrate pulsed current injection at a repetition rate exceeding 200 MHz as well as low-temperature operation down to 77 K of the fiber-coupled micropillar device. The technique presented in this work is an important step in the quest for efficient and practical quantum light sources for applications in quantum information.