A new approach of planar multi-channel wavelength division multiplexing system using asymmetric super-cell photonic crystal structures

This work demonstrated a new approach of planar multi-channel wavelength division multiplexing (WDM) system using photonic crystal structures. The system consists of a waveguide that is realized by a defect row of photonic crystal and high Q-value micro-cavities with asymmetric super-cell design. Two-Dimension (2-D) Finite-Difference-Time-Domain (FDTD) method is performed for simulation in this paper. The results showed good ability to filter an incident pulse into six spectral channels with a FHWM improved from 3.6 nm to 1.4 nm and the coherence length improved from 0.667 cm to 1.716 cm at the center wavelength 1550 nm channel and no transmission degradation. Six-channel coarse wavelength division multiplexing (CWDM) from 1490 similar to 1590 nm with channel spacing of 20 nm which defined by ITU-T Recommendation G. 694.2 are presented. And the inter-channel cross-talk is smaller than -17 dB. The device design is leading the way to achieve CWDM specification and has good capability to extend the application of communication filed and fiber optical sensor field.