Bragg scattering in a positive β_4 fiber

Abstract

The phase-matching curves for the four-wave mixing effect of Bragg scattering in two fibers with opposite sign β(4) dispersion coefficients have been measured experimentally. The measured phase-matching curves are in good agreement with theoretical expectations, and their dependence on several key parameters has been determined.

Bragg-Scattering Four-Wave Mixing in Nonlinear Fibers with Intracavity Frequency-Shifted Laser Pumps

“…Four-wave mixing is usually characterized as 3 distinct processes depending on the relative positions of the pumps, signal, and idler frequencies (see Figure 4(a)) [4,8]: modulation instability (MI), phase conjugation (PC), and Bragg-scattering (BS). All of them may be simultaneously observable [5] especially for low dispersion values, as it will be shown at the end of Section 4. MI requires one pump process.…”

“…For BS-FWM energy and momentum conservation give for angular frequencies ω j and wave-vector k j (j = P1, P2, S, for the pump 1, pump 2, signal and idler resp.) [4,5,11]:…”

“…In close proximity to the ZDW, the dispersion coefficient of an HNLF is generally approximated by a linear function of wavelength. Under this approximation, if one fixes for instance the wavelength of the pump 1, one can build a chart of optimization for the remaining wavelengths combining (1) and (2) [4,5]. An example for such a diagram is given in Figure 4(b) for a fiber with ZDW of 1545 nm and dispersion slope of 0.018 ps/(km nm 2 ).…”

“…In particular, optical parametric amplification, frequency conversion, phase conjugation, and nonlinear switching have been widely explored. The main interest was developed for FWM with coherent pumps, since this technique may provide high conversion efficiencies with appropriate dispersion curves [5]. Nevertheless, in recent years, FWM in optical fibers with incoherent or partially coherent pumps has attracted great attention, in view of its polarizationindependent gain and increased resilience to stimulated Brillouin scattering (SBS) [6,7].…”

“…For the case of two-pump parametric devices, optimal architectures of phase modulations have been proposed to suppress SBS. These solutions are based on phase modulators, generally driven by a pseudorandom bitsequence generator [4,5,8,9] at GHz repetition frequency. With pure phase modulation the pumps can be spectrally broadened without affecting the time domain intensity.…”