Multi/demulti-plexer based on transverse mode conversion in photonic crystal waveguides.

Area of Science:

• Photonics
• Optical Communications
• Materials Science

Background:

• Mode multiplexing/demultiplexing (MMUX/DEMUX) is crucial for increasing optical communication capacity.
• Photonic crystals (PCs) offer unique properties for novel optical device designs.
• Existing MMUX/DEMUX devices face challenges in insertion loss, crosstalk, and bandwidth.

Purpose of the Study:

• To propose and simulate a novel 2-D photonic crystal (PC) based mode multiplexer and demultiplexer (MMUX/DEMUX) operating at 1550 nm.
• To demonstrate the feasibility of mode conversion between TE(0) and TE(1) modes using quasi-phase-matching in coupled waveguides.
• To evaluate the performance of the proposed PC-based MMUX/DEMUX for high-capacity optical communication systems.

Main Methods:

• Design and simulation of a 2-D photonic crystal (PC) structure for MMUX/DEMUX.
• Utilizing quasi-phase-matching for TE(0) and TE(1) mode conversion between single-mode and multi-mode waveguides.
• Employing 2D Finite-Difference-Time-Domain (FDTD) and Beam Propagation Method (BPM) for optical performance analysis.

Main Results:

• The proposed PC-based MMUX/DEMUX exhibits low insertion loss (<0.36 dB).
• Achieved low mode crosstalk (< -20.9 dB) for effective signal isolation.
• Demonstrated a wide operational bandwidth of approximately 100 nm.

Conclusions:

• The novel 2-D PC MMUX/DEMUX shows significant potential for high-capacity wavelength division multiplexing (WDM) optical communication systems.
• The device offers excellent performance metrics, including low loss, low crosstalk, and wide bandwidth.
• This technology advancement could pave the way for more efficient and scalable optical networks.