Modeling, simulation, and fabrication of bi-directional mode-division multiplexing for silicon-on-insulator platform

Abstract

A strip waveguide-based bi-directional mode-division multiplexer is proposed. A mathematical model has been proposed to analyze the performance, and the results are simulated. The design concept of this device to (de)multiplex three modes simultaneously has been studied previously for slab waveguides, both mathematically using the perturbative mode-coupled theory and by simulation using 2D FDTD Solutions (FDTD, finite difference time domain). As slab waveguides are not suitable for extracting fabrication parameters for most silicon-on-insulator applications, we apply the concept to a more practical device that involves strip waveguides rather than slab waveguides. The effective index method (EIM) has been used to develop the mathematical model and to get approximate forms for both the profiles and coupling coefficients. The return loss of different modes is taken into consideration to fully characterize the device performance. Simple formulas for both insertion and return losses of all multiplexing modes have been derived. In addition, full vectorial 3D FDTD simulations are performed so as to validate our mathematical model. Different design parameters have been used to get numerical results of the proposed device. Our results reveal that the EIM has enough accuracy to characterize the performance of our device compared to that of the complex full vectorial simulation. In order to validate the used model, the device has been fabricated and tested. Good insertion losses and crosstalks for all modes have been obtained.

Photonic crystal-based compact hybrid WDM/MDM (De)multiplexer for SOI platforms

“…It has been realized for on-chip interconnect using a lot of approaches. DCs, Bragg gratings, RRs, MMIs, and asymmetric Y-junction techniques have been proposed in the literature [13][14][15][16][17][18][19].…”

International Journal of Electronics and Telecommunications

“…From the mode chart figure in [14], when the width increases, the difference in the effective index decreases thus the phase mismatch decreases. On the other hand, increasing the width will permit other undesired higher order modes to propagate thus increases the crosstalk.…”

“…, n effg l is the effective index of a slab waveguide of height h in y direction, λ o is the wavelength of operation, ρ = 2π λo n 2 1 − n 2 effg l , and ϕ = ρh/2 + lπ/2. B l is a constant that can be expressed as [14]:…”