  Entangled photon pairs are an important resource for quantum cryptography
schemes that go beyond point-to-point communication. Semiconductor
Bragg-reflection waveguides are a promising photon-pair source due to mature
fabrication, integrability, large transparency window in the telecom wavelength
range, integration capabilities for electro-optical devices as well as a high
second-order nonlinear coefficient. To increase performance we improved the
fabrication of Bragg-reflection waveguides by employing fixed-beam-moving-stage
optical lithography, low pressure and low chlorine concentration etching, and
resist reflow. The reduction in sidewall roughness yields a low optical loss
coefficient for telecom wavelength light of alpha_reflow = 0.08(6)mm^(-1).
Owing to the decreased losses, we achieved a photon pair production rate of
8800(300)(mW*s*mm)^(-1) which is 15-fold higher than in previous samples.
