The application provides a
broadband light vector measurement method and device based on I / Q
demodulation, which comprises the following steps: generating carrier-suppressed double-
sideband linear
frequency modulation light signals with fixed starting
frequency difference as a measurement
signal and a
local oscillator signal respectively; passing the measurement
signal through a light device to be measured to obtain a probe
light signal; coherently mixing the probe
light signal and the
local oscillator signal through a 90-degree optical mixer, extracting I / Q two-way electrical signals through a balanced
photodetector; constructing a complex signal to separate upper and lower sidebands and suppress mirror frequency interference, extracting fixed low-frequency components to obtain spectrum response information of the light device to be measured; obtaining the
system's own spectrum response through a calibration process; eliminating the
system response through complex division operation to obtain the
amplitude response and
phase response of the light device to be measured. The application can solve the spectrum
aliasing problem in symmetrical double-
sideband modulation without increasing the complexity of the
system, expand the measurement bandwidth by one time, speed up the measurement, and does not need a
wideband electrical amplitude and
phase detector, effectively reducing the
measurement cost.