Abstract：This paper describes a miniaturized quantum key distribution (QKD) transmitter for the BB84 protocol for short-range QKD applications between portable devices and hosts. The transmitter uses silicon PN junctions to generate photons and wire-grid polarizers for the polarization encoding. It also uses a convex lens and an aperture for collimation as well as to eliminate the photon spatial information. Simulations indicate that the transmitter can support a raw key generation rate of 3 kb/s and the polarization extinction ratio of the generated photons in each polarization state can reach 20 dB. The transmitter height can be as small as 5 mm, so the device can be integrated into portable devices such as mobile phones.
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2019, Vol. 59 
