Due to the gain competition effect, it is hard to simultaneously maintain oscillation at two frequencies in an optoelectronic oscillator (OEO) loop. In this paper, a study of the gain competition effect in a dual-frequency OEO is theoretically and experimentally demonstrated. The steady-state conditions in the dual-frequency OEO are theoretically analyzed by deriving dynamic equations. A nonlinear time-varying model, as well as its calculation methods, is carried out to design and study the dynamic process of the dual-frequency OEO. Thanks to this model, the waveform, spectrum, and amplitude evaluation of generated signals, as well as the gain variation in the OEO loop, are numerically simulated. Based on the theoretical analysis and numerical simulation results, three schemes that can suppress the gain competition effect are proposed, and the one based on wavelength division multiplexing (WDM) technology is experimentally realized. The experimental results show that the novel independently tunable dual-frequency OEO, to the best of our knowledge, can generate two-tone RF signals in a range from 1.8 to 18.6 and 1.5 to 18.3 GHz, respectively.
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http://dx.doi.org/10.1364/AO.509242 | DOI Listing |
We propose and experimentally demonstrate an injection-locked broadband optoelectronic oscillator (OEO) to generate freely tunable phase-locked dual-frequency microwave signals. When two single-tone signals inside and outside the passband of the electrical broadband bandpass filter (BPF) are, respectively, injected into the OEO, a phase-locked dual-frequency microwave signal with ultra-low near-end side-mode spurs can be generated from the OEO cavity. Therefore, one frequency of the output signal is equal to the frequency of the injected signal within the BPF, and the other frequency is equal to the sum frequency or the differential frequency of two injected signals.
View Article and Find Full Text PDFAn approach to generating stable phase-locked dual-frequency microwave signals is proposed and demonstrated based on a dual-passband optoelectronic oscillator (OEO). Mode gain competition is broken by employing frequency mixing mutual injection effect to realize phase locking between the two oscillation signals, which is achieved by applying a single-tone signal to a microwave mixer in the OEO cavity. In addition, a dual-loop configuration with balanced detection is utilized to ensure a high side mode suppression ratio (SMSR) and ultra-low phase noise, which also enhances the stability of the generated signal.
View Article and Find Full Text PDFDue to the gain competition effect, it is hard to simultaneously maintain oscillation at two frequencies in an optoelectronic oscillator (OEO) loop. In this paper, a study of the gain competition effect in a dual-frequency OEO is theoretically and experimentally demonstrated. The steady-state conditions in the dual-frequency OEO are theoretically analyzed by deriving dynamic equations.
View Article and Find Full Text PDFCoherent dual-frequency microwave signal generation using an optoelectronic oscillator (OEO) is presented and demonstrated. In the proposed OEO, a dual-band bandpass filter (DB-BPF) is utilized to select two oscillation modes. An external signal is injected into the OEO loop with its frequency equaling the frequency interval of the two oscillation modes.
View Article and Find Full Text PDFA high-accuracy distance measurements (DMs) approach based on beat frequency detection of a dual-frequency optoelectronic oscillator (OEO) is proposed and experimentally demonstrated. The dual-frequency OEO is formed with a single electro-optical modulator and a common length of energy storage fiber, and the beat frequency of the two oscillation signals can be directly achieved after a photodetector. Since the environmental disturbance has the same influence on the lengths of the two loops corresponding to the two oscillation frequencies, the environmental disturbance errors can be greatly reduced by beat frequency detection.
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