High quality-factor Si/SiO(2)-InP hybrid micropillar cavities with submicrometer diameter for 1.55-µm telecommunication band.

We theoretically demonstrate high quality(Q)-factor micropillar cavities at 1.55-µm wavelength based on Si/SiO(2)-InP hybrid structure. An adiabatic design in distributed Bragg reflectors (DBRs) improves Q-factor for upto 3 orders of magnitude, while reducing the diameter to sub-micrometer. A moderate Q-factor of ~3000 and a Purcell factor of ~200 are realized by only 2 taper segments and fewer conventional DBR pairs, enabling single photon generation at GHz rate. As the taper segment number is increased, Q-factor can be boosted to ~10(5)-10(6), enabling coherent exchange between the emitter and the optical mode at 1.55 µm, which is applicable in quantum information networks.

Design of Si/SiO2 micropillar cavities for Purcell-enhanced single photon emission at 1.55 µm from InAs/InP quantum dots.

Numerical simulations were carried out on micropillar cavities consisting of Si/SiO2 distributed Bragg reflectors (DBRs) with an InP spacer layer. Owing to a large refractive index contrast of ~2 in DBRs, cavities with just 4/6.5 top/bottom DBR pairs that give a low pillar height (~4.5 µm), have noticeable Purcell-enhancement effect in the 1.55-µm band. With careful designs on cavities with diameters of ~2.30 µm, a quality factor of up to 3300, a nominal Purcell factor of up to 110, and an output efficiency of ~60% are obtainable. These results ensure improvement of operation frequency and enhancement of photon indistinguishability for 1.55-µm single photon sources based on InAs/InP quantum dots.