Phase modulation parallel optical delay detector for microwave   angle-of-arrival measurement with accuracy monitored
  A novel phase modulation parallel optical delay detector is proposed for microwave angle-of-arrival (AOA) measurement with accuracy monitored by using only one dual-electrode Mach-Zenhder modulator. A theoretical model is built up to analyze the proposed system including measurement accuracy monitoring. The spatial delay measurement is translated into the phase shift between two replicas of a microwave signal. Thanks to the accuracy monitoring, the phase shifts from 5{\deg} to 165{\deg} are measured with less than 3.1{\deg} measurement error. 
Z. Cao, Q. Wang, R. Lu, H.P.A. van den Boom, E. Tangdiongga, and   A.M.J. Koonen
physics.optics