1 Design and analysis of slow light regime in silicon carbide 2d photonic crystal waveguides Elyar Pourali a , Mohammad Kazem Moravvej-Farshi a  , and Majid Ebnali-Heidari b a Faculty of Electrical and Computer Engineering, Advanced Device Simulation Lab, Tarbiat Modares University, PO Box 14115-194, Tehran, 1411713116 Iran. b Faculty of Engineering, Shahrekord University, Shahrekord 8818634141, Iran  Corresponding author: farshi_k@modares.ac.ir Abstract— We theoretically demonstrate the slow light capabilities of 2D silicon carbide based photonic crystal W1 waveguides (SiC-PhC-W1Ws) with numerical simulations. The PhC is assumed to be created by devising air-holes with hexagonal lattice in a standard SiC substrate having oscillator type ordinary refractive index. Numerical simulations show that by means of selective optofluidic infiltration and varying the air-holes radii, SiC-PhC-W1Ws are capable of slowing light down by about 473 times while their group velocity dispersions are tailored to near zero values. Our numerical study also suggests the possibility of slow-light guiding with n g ×∆λ/λ c values as high as 0.42 in SiC-PhC-W1Ws at optical telecommunications wavelengths. KEYWORDS: Dispersive Material, Dispersion Engineering, Photonic Crystal Waveguides, Silicon Carbide, Slow light Regime. 1. INTRODUCTION In recent years, there has been a growing interest in slow light in photonic crystals (PhC) [1], both for realizing compact optical functions and specifically for nonlinear photonics [1-8]. The slow light planar photonic crystal (PhC) waveguides have attracted a growing interest both in the context of optical delay lines and nonlinear optics. Presence of slow light in photonic crystal structures enhances light-matter interaction, due to longer time interval that light travels through the structure. However, the high group velocity dispersion (GVD) that usually accompanies the slow light regime distorts the optical pulses, compromising the advantage of slow light. As the light group velocity in a structure reduces, the physical length needed to observe either the linear or the nonlinear effects would be shorter than that in the fast light regime. Moreover, slow light regime can be beneficial in optical delay lines and optical buffers. One way to achieve slow light in crystal structures is to use selective optofluidic infiltration of air-hole PhC structure. By means of selective infiltration of PhC air-holes one can selectively control the structure properties as desired by varying the optical fluid refractive index and/or the air-holes dimensions [9]. There have been several reports on techniques of dispersion engineering by which the GVD in the slow light regime in PhC structures can be kept as low as possible and yet the optical pulse shape is maintained intact [9-15]. Those involve selective optofluidic infiltration of PhC air-holes [9], use of ring shaped holes [10], and varying the waveguide dimension [11], the air-holes radii [12], or their position [13-15], or by slightly modifying the PhC waveguide geometry [16-19]. We simulate a control scheme that can be realized by optofluidic infiltration. The details of practicality, advantages, and disadvantages of this technique have been repeatedly described elsewhere [9, 20-22].