Phase noise modeling and characterization of a self-started VCSEL-based harmonic frequency generator (SVHFG)

This article presents the experimental characterization of the first self-started closed-loop system for the generation of microwave harmonics using a long-wavelength VCSEL modulated in a gain-switched regime. A 15-GHz microwave signal is generated with a phase noise of −104 dBc/Hz at 10 kHz from the carrier when the fundamental frequency is GHz. The side-mode suppression ratio (SMSR) for all the microwave frequencies generated is higher than 30 dB. We propose a predictive model to estimate the phase noise of the fundamental oscillating frequency, considering the noise contributions of each loop component. Several simulation scenarios are included to demonstrate the significant influence of the electrical power, the laser frequency noise, and the optical fiber dispersion over the phase noise performance. We also present the carrier-to-noise ratio deterioration of the microwave harmonics distributed through an optical fiber link