Generation of frequency-modulated sub-terahertz signal using microwave photonic technique

We present a photonic technique for generating a frequency- modulated sub-terahertz signal for non-destructive or noninvasive sensing and imaging applications. Large frequency deviation was achieved by using optical phase modulation and heterodyne photomixing with an uni-travelling photodetector. The operation principle is theoretically derived and explained. In addition, the generation of 350-GHz frequency- modulated sub-terahertz signal with 6.7-GHz frequency deviation is experimentally demonstrated, and the possibility of frequencies up to 1 THz and wider frequency deviations is discussed.