Optical generation, distribution, and control of microwaves using laser heterodyne

Demonstrated is the optical generation and transmission of a microwave signal by the mixing of two high-quality optical signals from diode-laser-pumped Nd:YAG ring lasers, resulting in a narrow microwave line width (less than 5 kHz line width at 3 dB and less than -115 dBc/Hz at 300 kHz from line center) and broad microwave tunability (DC to 52 GHz). A III-V semiconductor waveguide with a doping superlattice active region is used to optoelectronically provide 20 dB of amplitude control and up to 5 pi of phase shift. This approach can be straightforwardly implemented using integrated optics and fiberoptic links for control of phased-array antenna elements.<
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