A hybrid optical time delay unit using lithium niobate switches and pr
ecisely produced fiber loops is described, Three prototypes of the dev
ice were fabricated and characterized, The measured optical extinction
ratio between time slots is typically much less than 25 dB. On averag
e, delay values are within 0.7% of their design values, The device is
a 6-b (64 time slot) delay unit with 44 picosecond per increment.