Single-photon interference over 150-km transmission using silica-based   integrated-optic interferometers for quantum cryptography
  We have demonstrated single-photon interference over 150 km using time-division interferometers for quantum cryptography, which were composed of two integrated-optic asymmetric Mach-Zehnder interferometers, and balanced gated-mode photon detectors. The observed fringe visibility was more than 80% after 150-km transmission. 
Tadamasa Kimura, Yoshihiro Nambu, Takaaki Hatanaka, Akihisa Tomita,   Hideo Kosaka, and Kazuo Nakamura