  The combination of semiconductor quantum dots (QDs) with photonic cavities is
a promising way to realize non-classical light sources with state-of-the-art
performances in terms of brightness, indistinguishability and repetition rate.
In the present work we demonstrate the coupling of an InGaAs/GaAs QDs emitting
in the telecom O-band to a circular Bragg grating cavity. We demonstrate a
broadband geometric extraction efficiency enhancement by investigating two
emission lines under above-band excitation, inside and detuned from the cavity
mode, respectively. In the first case, a Purcell enhancement of 4 is attained.
For the latter case, an end-to-end brightness of 1.4% with a brightness at the
first lens of 23% is achieved. Using p-shell pumping, a combination of high
count rate with pure single-photon emission (g(2)(0) = 0.01 in saturation) is
achieved. Finally a good single-photon purity (g(2)(0) = 0.13) together with a
high detector count rate of 191kcps is demonstrated for a temperature of up to
77K.
