Deterministically fabricated strain-tunable quantum dot single-photon sources emitting in the telecom O-band

Abstract

Most quantum communication schemes aim at the long-distance transmission of quantum information. In the quantum repeater concept, the transmission line is subdivided into shorter links interconnected by entanglement distribution via Bell-state measurements to overcome inherent channel losses. This concept requires on-demand single-photon sources with a high degree of multi-photon suppression and high indistinguishability within each repeater node. For a successful operation of the repeater, a spectral matching of remote quantum light sources is essential. We present a spectrally tunable single-photon source emitting in the telecom O-band with the potential to function as a building block of a quantum communication network based on optical fibers. A thin membrane of GaAs embedding InGaAs quantum dots (QDs) is attached onto a piezoelectric actuator via gold thermocompression bonding. Here, the thin gold layer acts simultaneously as an electrical contact, strain transmission medium, and broadband backside mirror for the QD-micromesa. The nanofabrication of the QDmicromesa is based on in situ electron-beam lithography, which makes it possible to integrate pre-selected single QDs deterministically into the center of monolithic micromesa structures. The QD pre-selection is based on distinct single-QD properties, signal intensity, and emission energy. In combination with strain-induced fine tuning, this offers a robust method to achieve spectral resonance in the emission of remote QDs. We show that the spectral tuning has no detectable influence on the multi-photon suppression with g (2) (0) as low as 2%-4% and that the emission can be stabilized to an accuracy of 4 leV using a closed-loop optical feedback.

Chip-Scale Quantum Emitters

“…In commercialized quantum communication, the quantum information must be transferred over long distances. However, to avoid the loss of data over a long communication distance, the quantum repeater is needed to subdivide the transmission line into several segments interconnected by entanglement distribution via Bell-state measurements to overcome inherent channel losses [44]. Consequently, high indistinguishability within each repeater node is necessary.…”

“…This can be supplied by single-photon sources demonstrating evidence of strong multiphoton suppression. To build and make a repeater with a successful operation, the matching of spectral features between quantum light sources must be achieved [44]. Recently, a spectrally tunable single-photon source was developed that can emit in the telecom O-band [44].…”

“…To build and make a repeater with a successful operation, the matching of spectral features between quantum light sources must be achieved [44]. Recently, a spectrally tunable single-photon source was developed that can emit in the telecom O-band [44]. Accordingly, a coupling between a piezoelectric actuator via gold thermocompression bonding and a thin membrane of GaAs embedding InGaAs quantum dots (QDs) was used to produce a tunable single-photon source [44].…”

“…Recently, a spectrally tunable single-photon source was developed that can emit in the telecom O-band [44]. Accordingly, a coupling between a piezoelectric actuator via gold thermocompression bonding and a thin membrane of GaAs embedding InGaAs quantum dots (QDs) was used to produce a tunable single-photon source [44]. Here, the role of electrical connection was played by a thin gold layer-which acts as a strain transfer structure-and broadband backside mirror for the QD micromesa that was prepared by in situ electron-beam lithography [44].…”

“…Accordingly, a coupling between a piezoelectric actuator via gold thermocompression bonding and a thin membrane of GaAs embedding InGaAs quantum dots (QDs) was used to produce a tunable single-photon source [44]. Here, the role of electrical connection was played by a thin gold layer-which acts as a strain transfer structure-and broadband backside mirror for the QD micromesa that was prepared by in situ electron-beam lithography [44]. Experimental results showed that the multiphoton suppression had not been influenced by spectral tuning [44].…”