Microwave Photonic Noise Source From Microwave to Sub-Terahertz Wave Bands and Its Applications to Noise Characterization

In this paper, we present a microwave photonic technique to produce a noise signal from the microwave to sub-terahertz region with an optical amplified spontaneous emission noise, optical filter, and photodetector. With this scheme, it is easy to control the noise level by simply controlling the input optical noise power. In addition, the output noise spectral density with this scheme can be accurately estimated from the well-known spectral shape of an optical filter. For the demonstration of this scheme as a noise source, noise figure measurements for commercial devices such as amplifiers and a mixer, were performed in the frequency range from 0.1-20 to 293-357 GHz and the results were compared to those with conventional techniques.