Single-shot high-speed signal detection by multiple-angle spectral interferometry

A novel technique for detecting ultra-fast signals at speeds beyond those of conventional electrical circuits is described that uses the coherent correlation between the signal wave and that of a modulated local oscillator. The spectral components of the signal beam interfere with their counterparts of the light from the local oscillator in a multiple-angle scheme. It is found that this scheme allows the mutual convolution of the interfering lights to be spatially displayed on the observation plane as an interference pattern. Typical applications of this technique include serial-to-parallel conversion of the signal light and packet detection. In an experiment, single-event high-speed signals of several mW are successfully detected by using two independently oscillating light sources for the signal and local beams. Finally, we discuss the deployment of this technique in optical communication systems.