Four-wave mixing and octave-spanning supercontinuum generation in a small core hydrogenated amorphous silicon fiber pumped in the mid-infrared

Abstract

An octave-spanning supercontinuum is generated in a hydrogenated amorphous silicon core fiber when pumped in the mid-infrared regime. The broadband wavelength conversion which extends from the edge of the telecommunications band into the mid-infrared (1.64-3.37 μm) is generated by four-wave mixing (FWM) and subsequent pulse break-up, facilitated by the high material nonlinear figure of merit and the anomalous dispersion of the relatively small 1.7 μm diameter core fiber. The FWM sidebands and corresponding supercontinuum can be tuned through the pump parameters, and show good agreement with the predicted phase-matching curves for the fiber.

Semiconductor optical fibers

“…Fig. 2(b) shows broadband supercontinuum generated via a cascaded four-wave mixing process in a small core (D ∼ 2 µm) silicon fiber, recorded for two different pump wavelengths [3]. For the longer pump wavelength we have obtained a continuum spanning more than an octave, which we attribute to the lower linear and nonlinear losses of the silicon material in this region, thus motivating a shift to investigate the use of these fibers within the mid-infrared region.…”

“…1(b)], or by employing standard fiber post-processing procedures such as tapering [ Fig. 1(c)], it is also possible to tailor the waveguide design far beyond what is achievable on-chip, of particular use for nonlinear applications [3]. In this paper we review our efforts regarding the optical characterization of a range of semiconductor optical fibers, fabricated by both high pressure deposition and molten core drawing methods.…”

Glass and Process Development for the Next Generation of Optical Fibers: A Review

“…Initial activities focused on all-optical modulation in amorphous silicon of a fairly small core size [126]. Subsequently, the nonlinear transmission [127], two-photon absorption (TPA) [128], cross-phase modulation (XPM) [129], four-wave mixing (FWM) and super-continuum generation (SC) [130] all have been investigated. As nonlinear effects generally are enhanced at small core sizes, tapering of the fiber also has been employed and has yielded soliton generation [131] and the first observation of nonlinear transmission within a polycrystalline silicon waveguide of any type [132].…”

Semiconductor optical fibers for nonlinear applications

“…3(b) shows the first observation of supercontinuum generation in a semiconductor core fiber. 20 These results were obtained by using a smaller core fiber (D ∼ 2 µm) and moving the pump source to longer wavelengths (beyond the TPA edge) to access a region of lower nonlinear loss. More significantly, for this fiber the zero dispersion wavelength was λ z ∼ 2.1 µm so that it was possible to access the anomalous dispersion regime, where the spectral broadening can be enhanced through phase-matched four-wave mixing and soliton fission.…”