Broadband and Wideband Parametric Gain via Intermodal Four-Wave Mixing in Optical Fiber

Intermodal Bragg-Scattering Four Wave Mixing in Silicon Waveguides

“…9 (insets). It is also worth noting that much broader bandwidths are to be expected by properly engineering the group index of the two spatial modes such that they are shifted replicas of one another at the wavelengths of interest [14], or exhibit a mirror symmetry [26].…”

“…In this work, we demonstrate the uni-directionality of the FWM BS process by exploiting the spatial modes of a multi-mode silicon waveguide. The extra degree of freedom given by the capability to carefully excite and control higher order modes in multi-mode nonlinear waveguides offers more options to fulfill the required phase matching [12], [13], [14], [15], [16]. Thus, multiple discrete spectral bands can be simultaneously phase matched, leading to simple scalable and controllable discrete wavelength converters that can be largely detuned from the pump(s) wavelengths by exciting phase matched and dispersion tailored modes of a single multi-mode nonlinear waveguide.…”

Silicon Photonics Wavelength Converter based on Inter-Modal Four Wave Mixing Bragg Scattering

“…The operational principle of the wavelength converter is illustrated in Fig. I (a) [2]. The figure shows the simulated group index curves of the first four supported modes as a function of wavelength propagating in our multi-mode waveguide.…”

“…Inter-modal phase matching is achieved when the propagation constants of the interacting waves satisfy conservation of momentum (as well as conservation of energy). This occurs when the value of the group index of the various modes evaluated at the average wavelength of the waves in the same mode (pump-pump and signal-idler pairs in this instance) are equal [2], [3], see dashed black line in Fig. I (a).…”

“…Optical wavelength conversion is typically realized exploiting four wave mixing (FWM), where the input signal information is transferred to the desired wavelength via a nonlinear process, which requires phase matching among the interacting waves. This is achieved by tailoring the waveguide geometry to engineer the group velocity dispersion and, while it is very effective, it imposes stringent trade-offs in single mode engineered waveguide designs, particularly if extremely broad and wide-band systems are simultaneously required [2]. Multi-mode nonlinear waveguides, possessing the extra degree of freedom given by the capability to carefully excite and control higher order modes, offer more ways to fulfill the required phase matching, in principle allowing for broadband operation at multiple discrete spectral bands, even at spectral locations far away from the pump wavelength(s).…”