Spherical Fourier Cell and Application for Optical True Time Delay

A new optical configuration for switching light beams called a spherical Fourier cell is explained. Its use for optical true time delay is outlined. An experimental apparatus was constructed for a 6-bit delay system, with 2 bits demonstrated. Delays of 0, 2.1, 4.1, and 6.2 ns were measured. Loss and crosstalk measurements are also given.