Design optimization for bright electrically-driven quantum dot single-photon sources emitting in telecom O-band

A combination of advanced light engineering concepts enables a substantial improvement in photon extraction efficiency of micro–cavity–based single–photon sources in the telecom O–band at ∼1.3 µm. We employ a broadband bottom distributed Bragg reflector (DBR) and a top DBR formed in a dielectric micropillar with an additional circular Bragg grating in the lateral plane. This device design includes a doped layer in pin–configuration to allow for electric carrier injection. It provides broadband (∼8–10 nm) emission enhancement with an overall photon–extraction efficiency of ∼83% into the upper hemisphere and photon–extraction efficiency of ∼79% within numerical aperture NA=0.7. The efficiency of photon coupling to a single–mode fiber reaches 11% for SMF28 fiber (with NA=0.12), exceeds 22% for 980HP fiber (with NA=0.2) and reaches ∼40% for HNA fiber (with NA=0.42) as demonstrated by 3D finite–difference time–domain modeling.