Abstract
We propose an approach for an efficient generation of optical Cherenkov radiation (OCR) in the near-infrared by tailoring the waveguide dispersion for a zero group-velocity mismatching between the radiation and the pump soliton. Based on an As(2)S(3) slot waveguide with subwavelength dimensions, dispersion profiles with four zero dispersion wavelengths are found to produce a phase-matching nonlinear process leading to a broadband resonant radiation. The broadband OCR investigated in the chalcogenide waveguide may find applications in on-chip wavelength conversion and near-infrared pulse generation.
Highlights
Optical Cherenkov radiation (OCR), referred to as dispersive wave generation or nonsolitonic radiation, originates from soliton propagation perturbed by high order dispersion (HOD)
Most OCRs have been widely explored based on the dispersion profiles with one or two zero-dispersion wavelengths (ZDWs), in which the resonant radiations usually fall into the normal group velocity dispersion (GVD) region
We demonstrate an efficient broadband OCR in an As2S3 slot waveguide with four ZDWs
Summary
Optical Cherenkov radiation (OCR), referred to as dispersive wave generation or nonsolitonic radiation, originates from soliton propagation perturbed by high order dispersion (HOD). Chromatic dispersion influences the OCR frequencies through the PM condition [7, 8]: βs(ωr) = β (ωr), where βs(ω) ≡ β (ωp) + β (1)(ω − ωp) + γ · P/2 reflects the nondispersive nature of a soliton, β (ω j) is the frequency dependent propagation constant and β n(ω j) is n-th order derivative of β at ω j, j = r or p represents the radiation or pump wave. We investigate near-infrared OCRs in an As2S3 slot subwavelength waveguide by engineering its dispersion, and present a numerical analysis of a broadband radiation due to a zero group-velocity (GV) mismatch and broadband phase-matched nonlinear process. Broadband OCR can serve as a new wavelength conversion scheme to achieve large conversion spanning. More important, it tends to a stable soliton state upon propagation, distinguished from linear radiations in the blue edge of the SCG.
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