Frequency response measurement of half-wave voltage and chirp parameter of LiNbO3 intensity modulators in low frequency range

We measured frequency responses of half-wave voltage V
_π
and chirp parameter α
₀
of LiNbO
₃
modulators below 1 GHz range using optical heterodyne scheme with an acousto-optic modulator. The coefficients of variation of the measured values of V
_π
and α
₀
are 0.2 % and 2 %, respectively. We observed strong dependency of V
_π
and α
₀
on the frequency.