  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.
