Generation of Broadband Flat Millimeter-Wave White Noise Using Rectangular ASE Slices Mixing

Millimeter-wave white noise enables promising applications in MMW communication systems. However, current generation methods for this type of source suffer from small bandwidth and uneven spectrum. Herein, we propose and demonstrate an effective method for flat millimeter-wave white noise generation by slicing the broadband spectrum of amplified spontaneous emission (ASE) into two rectangular spectra and mixing on a photodetector. The bandwidths of the two rectangular ASE slices used for optical mixing are key factors affecting the bandwidth and power level of the flat-spectrum noise. As a feasible demonstration, the MMW white noise with a flatness of +/- 1.75 dB (@130-170 GHz) was experimentally achieved by mixing two rectangular ASE slices with bandwidths of 20 GHz and 60 GHz, respectively. Our proposed scheme takes full advantage of the bandwidth of high-speed photodetector and promises great potential for generating white noise with substantial flatness in the millimeter-wave and even terahertz bands.