Dispersion effects on the performance of whispering gallery mode based optoelectronic oscillators

Optoelectronic oscillators (OEOs) have attracted much attention for producing ultra-low phase-noise microwave/millimeter-wave oscillations. Traditional delay-based OEOs usually suffer from strong spurious peaks in their phase noise power spectral densities and possible mode-hopping phenomena. Some methods have been proposed in the literature such as using multi-loop architectures or injection locking to other OEOs or radio frequency (RF) oscillators to reduce these spurious peaks. In other approaches, optical filters/resonators other than optical fibers have been proposed to reduce or suppress these peaks and prevent the mode-hopping phenomenon, such as whispering gallery mode resonators (WGMRs), fiber Bragg gratings, and other forms of microwave photonic filters. Usually, approximate single-purpose approaches have been presented to analyze OEOs utilizing such resonators. Here a general framework for analyzing the performance of OEOs implementing RF and optical filters/resonators with arbitrary linear transfer functions is presented. Consequently, it can consider, for example, the most general dispersion models of the fibers as well as any OEO architecture using a combination of different optical resonators. It can also consider the noise transfer between any sidebands of the RF or optical signals and any kind of amplitude noise to phase noise transfers and vice versa. The non-idealities of the electro-optic modulators such as the chirping and finite extinction ratios can also be taken into account. The validity of the new approach is verified by comparing its results with those previously published in the literature. In particular, the case of a WGMR plus delay line OEO is considered for comparisons.

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Frequency tunable optoelectronic oscillator with parity-time symmetry by using integrated components

Ahmadfard,

Hosseini,

Qashqaei

2024

J. Opt. Soc. Am. B

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This study introduces a parity-time (PT) symmetric, frequency-tunable optoelectronic oscillator (OEO) using integrated components within a dual-polarization Sagnac loop (SL). By leveraging the natural birefringence of a Z-cut lithium niobate (LiNbO3) phase modulator, interconnected optoelectronic loops with orthogonally polarized light waves are established—one experiencing gain and the other loss. Fine-tuning the polarization states through multiple polarization controllers (PCs) enables precise control over the gain and loss coefficients, achieving the PT symmetry breaking condition necessary to generate a stable, single-frequency microwave signal. The integrated components––the phase modulator (PM), the SL, and the photodetector (PD)––function as a microwave photonic filter (MPF). A tunable laser source combined with a microheater-tuned microdisk resonator (MDR) allows precise frequency adjustments, enabling tunable microwave frequencies from 2 to 12 GHz without additional filters. This integrated approach simplifies the system, reduces its footprint, and enhances the stability against environmental factors. Simulation results demonstrate that the proposed OEO design generates a stable, frequency-tunable microwave signal, achieving single-mode oscillation at 11.8 GHz with a phase noise of −122.5dBc/Hz at a 10 kHz offset frequency.

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Dispersion effects on the performance of whispering gallery mode based optoelectronic oscillators

Cited by 3 publications

References 21 publications

Uncertainty Evaluation on a 10.52 GHz (5 dBm) Optoelectronic Oscillator Phase Noise Performance

Uncertainty Evaluation on a 10.52 GHz (5 dBm) Optoelectronic Oscillator Phase Noise Performance

Frequency domain analysis of optoelectronic oscillators utilizing optical and RF resonators with arbitrary transfer functions

Frequency tunable optoelectronic oscillator with parity-time symmetry by using integrated components

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