Integrated implementation of ultra stable VCO using optical Self-ILPLL techniques

Abstract

A cost effective realization of optically Self-ILPLL of a state of the art phase locked DRO system at 10GHz in a 19″ rack mountable box is realized with phase noise of -132dBc/Hz at 10 kHz offset carrier. Long optical delay lines of 3km and 5km are respectively used for achieving self-dual phase locking (SPLL) and self-injection locking (SIL) at 10GHz. Phase noise of this DRO is reduced from -83.0dBc/Hz to -104.5dBc/Hz at 1kHz offset using a SIL (1km) and dual-SPLL (3km and 5km) as an optical DSILPLL. The fiber optic delay line performances and their attributed residual phase noise are compared in terms of attained noise figure. The low-cost integrated DFB with Electro-Absorption Modulator (EAM-LD) resulted in 45dB noise figure, whereas single electrode and push-pull amplified dual electrodes Mach-Zehnder Modulator (MZM) resulted in noise figures of 44dB and 32dB, respectively using large linewidth DFB lasers.