Abstract
We review the generation of entangled photon pairs at telecommunication wavelengths using a periodically poled lithium niobate (PPLN) waveguide. The characteristics of photon pairs generated using a type II PPLN waveguide are described in detail. We also briefly explain the principle of high speed single-photondetection at 1550nm using an InGaAs/InP avalanche photodiode operated with a sine wave gating.