Design of Si/SiO_2 micropillar cavities for Purcell-enhanced single photon emission at 155 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.