IEEE 14- An Optical Approach to Microwave Frequency Measurement With Adjustable Measurement Range and Resolution


We propose an approach for the measurement of
microwave frequency in the optical domain with adjustable measurement
range and resolution. In the proposed approach, two
optical wavelengths with a large wavelength spacing are modulated
by an unknown microwave signal in a Mach–Zehnder modulator
(MZM). The optical output from the MZM is sent to a dispersive
fiber to introduce different chromatic dispersions, leading to different
microwave power penalties. The two wavelengths are then
separated, with the microwave powers measured by two photodetectors.
A fixed relationship between the microwave power ratio
and the microwave frequency is established. The microwave frequency
is estimated by measuring the two microwave powers. The
frequency measurement range and resolution can be adjusted by
tuning the wavelength spacing. Different frequency measurement
ranges and resolutions are demonstrated experimentally.