Polarization insensitive wavelength conversion in a dispersion-engineered silicon waveguide

Abstract

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Polarization Insensitive Wavelength Conversion in a Low-Birefringence SiGe Waveguide

“…Similar optical characteristics for the TE and TM modes of the medium ensure the achievement of good linear and nonlinear phase matching simultaneously among all beams propagating along the two orthogonal axes of the device [16]. This is in contrast to the angled pump scheme [11] where phase matching conditions are satisfied separately in each orthogonal projection (TE and TM) and adjustment of the state of polarization of the pump(s) is subject to both the pump power and wavelength, In this work, the nonlinear device used was a Si0.8Ge0.2 strip waveguide embedded in Si (the choice of Ge concentration was based on our earlier characterization study concluding that a Ge concentration of 20% results in the highest nonlinear figure of merit for the majority of waveguide widths studied). A full waveguide analysis was carried out by means of a Finite Elements Method (FEM) solver to study the optical characteristics of waveguide.…”

“…While FWM is an inherently polarization-dependent process requiring accurate control of the state of polarization of the mixing waves, implementations that achieve polarization insensitive operation have been proposed. Such schemes employing either two orthogonally polarized pumps [9] or polarization diversity [10] have already been widely demonstrated in fiber-based devices, but their adoption in silicon-based systems is still rather limited [11,12]. Polarization diversity is widely used in photonics to overcome the strong birefringence of devices.…”

Polarization-insensitive wavelength conversion of 40 Gb/s NRZ-DPSK signals in a silicon polarization diversity circuit

“…At the device level, polarization-insensitive wavelength conversion has been demonstrated in semiconductor optical amplifiers (SOAs) [9,10] and periodically-poled lithium niobate (PPLN) waveguides [11][12][13][14]. Recently, polarization-insensitive wavelength conversion has also been described [15] and demonstrated in silicon waveguides [16], which constitute a very promising nonlinear platform thanks to their high nonlinear coefficients and strong confinement allowing compact-size devices to be fabricated, as well as their compatibility with complementary metal-oxide-semiconductor (CMOS) fabrication technology, enabling device integration. The drawback of the angle-pump scheme applied in [16] is the fact that the waveguides should be engineered so that they have similar dispersive properties for the TE and TM modes, which may restrict the possibilities to simultaneously achieve a large conversion bandwidth and high conversion efficiency (CE).…”

Forward error correction supported 150 Gbit/s error-free wavelength conversion based on cross phase modulation in silicon

“…Furthermore, silicon based wavelength conversion has attracted considerable research interest lately, due to its complementary metal-oxide-semiconductor (CMOS) compatibility, ultra-compactness and potential for integration with electronics [3][4][5][6][7][8][9][10][11][12][13]. One method for silicon based wavelength conversion is using four wave mixing (FWM), which usually requires broadband phase matching [3][4][5][6][7][8][9].…”

“…One method for silicon based wavelength conversion is using four wave mixing (FWM), which usually requires broadband phase matching [3][4][5][6][7][8][9]. Another way to achieve wavelength conversion is using cross phase modulation (XPM) [11][12][13][14].…”