Nonlinear Silicon Photonic Signal Processing Devices for Future Optical Networks

Abstract

Abstract:In this paper, we present a review on silicon-based nonlinear devices for all optical nonlinear processing of complex telecommunication signals. We discuss some recent developments achieved by our research group, through extensive collaborations with academic partners across Europe, on optical signal processing using silicon-germanium and amorphous silicon based waveguides as well as novel materials such as silicon rich silicon nitride and tantalum pentoxide. We review the performance of four wave mixing wavelength conversion applied on complex signals such as Differential Phase Shift Keying (DPSK), Quadrature Phase Shift Keying (QPSK), 16-Quadrature Amplitude Modulation (QAM) and 64-QAM that dramatically enhance the telecom signal spectral efficiency, paving the way to next generation terabit all-optical networks.

Characterization and Optimization of a High-Efficiency AlGaAs-On-Insulator-Based Wavelength Converter for 64- and 256-QAM Signals

“…However, silicon-based compounds may be more attractive as they could enable benefiting from the well established CMOS fabrication technology. In this regard, several material platforms have been investigated, spanning from crystalline [9] and amorphous silicon [15], to silicon-germanium [15], [16] and siliconnitride [17], as well as high index doped glass [18].…”

“…While successful approaches have been reported to actively mitigate the impact of free-carrier effects [4], materials such as amorphous silicon and silicon-germanium allow to decrease the impact of TPA as reported in [15], [19]. Successful demonstration of wavelength conversion for QAM signals have been recently reported in both platforms [15], [20] without requiring active TPA suppression. However, these materials are still affected by significant propagation loss (≈ 5 dB/cm) and further limited by the lower but still present TPA.…”

Octave spanning supercontinuum in titanium dioxide waveguides

“…To this aim, various platforms have been successfully investigated: Si [9][10][11], SiGe [12][13][14], SiN [15][16][17][18], diamond-on-insulator [19], chalcogenide waveguides [20] or III-V material based waveguides (InGaP [21]) and AlGaAs [22]. Each material provides specific advantages but also strong potential limitations including two photon absorption (TPA) and associated free carrier absorption, high level of losses, limiting transparency window, low refractive index, low handling power as well as high cost or complex manufacturing processes.…”

Group-velocity dispersion in SOI-based channel waveguides with reduced-height

“…The strong modal confinement occurring in these structures also implies that the optical intensity in these waveguides is much larger (by 2 or 3 orders of magnitude) than that in standard single-mode fibers. As a consequence, these structures have proven to be ideal candidates for all-optical signal processing thanks to highly efficient non-linear optical effects [2,3] and, thanks to the nonlinear effects occurring in standard (220 nm high) SOI waveguides, many interesting results have already been reported in the scientific literature [4][5][6]. Differently from what has been thoroughly studied in the last decade, in this paper we focus our attention on reduced-height waveguides (100 nm), with different waveguide widths (from 500 to 800 nm).…”