Abstract—Photonic generation of a phase-coded or frequencychirped
microwave waveform with a tunable microwave carrier
frequency using a frequency-tunable optoelectronic oscillator
(OEO) is proposed and experimentally demonstrated, for the
first time to the best of our knowledge. In the proposed system,
the tunable OEO has functions to generate a frequency-tunable
microwave signal and to output an optical sideband. The optical
sideband and a portion of the light wave from theOEO laser source
are sent to a polarization modulator (PolM), with their polarization
directions aligned with the two principal axes of the PolM.
An electrical signal is applied to the PolM, and two complementary
phase-coded or frequency-chirped light waves are generated
which are converted to an electrical signal by beating the light
waves at a high-speed photodetector. The key significance of the
technique is that a phase-coded or frequency-chirped microwave
waveform with a tunable microwave carrier frequency and a reconfigurable
phase-coding or frequency-chirping pattern can be
generated without using a separate microwave source. The technique
is experimentally verified. The generation of a binary- and
a polyphase-coded microwave waveform with a microwave carrier
frequency at 10 and 15 GHz is demonstrated. The generation of a
linearly frequency-chirped microwave waveform with a chip rate
of 20.98 GHz/ns at a 10-GHz carrier frequency and 22.5 GHz/ns
at a 15-GHz carrier frequency is also achieved.
Index Terms—Microwave photonics, microwave signal generation,
optoelectronic oscillator (OEO), phase coding, polarization