• Photonics Research
  • Vol. 12, Issue 8, 1785 (2024)
Hui Liu1,2, Mingyang Guo1,2, Tian Zhang1,2, Jian Dai1,2,*, and Kun Xu1,2
Author Affiliations
  • 1State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876, China
  • 2School of Electronic Engineering, Beijing University of Posts and Telecommunications, Beijing 100876, China
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    DOI: 10.1364/PRJ.522880 Cite this Article Set citation alerts
    Hui Liu, Mingyang Guo, Tian Zhang, Jian Dai, Kun Xu, "Ultralow-phase-noise and broadband frequency-hopping coupled optoelectronic oscillator under quiet point operation," Photonics Res. 12, 1785 (2024) Copy Citation Text show less

    Abstract

    Advancements in microwave photonics have yielded novel approaches for generating high-purity microwave sources. Among these, optoelectronic oscillators (OEOs) and coupled optoelectronic oscillators (COEOs) have demonstrated the capability to generate frequency-independent microwaves with exceptionally low phase noise. Nonetheless, the tunability of the oscillators is rather limited due to the necessity for narrowband electronic bandpass filters, presenting challenges in achieving both wide and rapid tuning capabilities. Here, we present a COEO featuring ultralow phase noise, flexible tuning capability, and high robustness. This is achieved through a quiet point (QP)-operated harmonic mode-locked fiber laser, which effectively mitigates optical amplifier noise and supermode competition, thus significantly diminishing the necessity for ultra-narrow electronic filters. Due to the liberated tuning ability, we present an oscillator that can be tuned from 2 GHz to 18 GHz, with phase noise as low as -140dBc/Hz at 10 kHz under the QP operation. We then illustrate the practical application of the proposed oscillator in generating frequency-hopping signals with consistent spurious modes less than -85dBc, absolute phase noise below -135dBc/Hz at 10 kHz, hopping resolution of 1.25 MHz, and fractional frequency stability below 6.1×10-12 at 1 s averaging time when locked to a reference. The presented COEO structure emerges as a compelling solution for agile and low-noise microwave sources in advanced wireless communication and radar systems.
    TRF=T0+δTTRT,

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    δtm<12βωmτ2,

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    Sϕ1(f)=(G1)hvnsGPin,

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    Sϕ2(f)=(G1)(2πKΓ/λA)24nsτc2PinGhv[(2πfτc)2+1],

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    Hui Liu, Mingyang Guo, Tian Zhang, Jian Dai, Kun Xu, "Ultralow-phase-noise and broadband frequency-hopping coupled optoelectronic oscillator under quiet point operation," Photonics Res. 12, 1785 (2024)
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