A new electro-optic modulator is designed and constructed. It is suita
ble for maintaining modulation at a high frequency and can be used to
generate ultra-wide-sideband signals to form ultrashort optical pulses
. In experiments, phase modulation with a modulation index of 57 rad i
s successfully obtained at 16.25 GHz, and thereby optical sidebands ex
tending over widths as wide as 1.85 THz are attained. The sidebands pr
oduced are broad enough to form subpicosecond pulses using the chirpin
g-compression method. (C) 1996 Society of Photo-Optical Instrumentatio
n Engineers.