Theoretical modelling of one dimensional photonic crystal based optical demultiplexer

Abstract

An optical demultiplexer through one-dimensional Si–SiO₂ photonic crystal structure in the presence of air cavity with a single crystal PMN-0.38PT material is presented. The transmittance of this structure is obtained using the transfer matrix method. The transmittance of this structure shows a sharp passband in the band gap region. It is observed that by introducing PMN-0.38PT layer in both sides of the air cavity, the existing band gap region of Si–SiO₂ structure is slightly increased. Here, PMN-0.38PT material is working as a tunable element for passband. By applying some external potential on PMN-0.38PT crystal, the thickness of cavity layer can be tuned and the passband can be placed at any desired wavelength in the band gap region. Since the photonic band gap region contains a range of wavelengths which are not allowed to pass through the structure  can be considered as a multiplex signal for the proposed demultiplexer. Therefore, any optical signal that lies in the band gap region of the structure can be separated into its components as a pass band. Hence, the proposed structure will work as an optical demultiplexer.

Keywords:

• photonic crystals
• optical demultiplexer
• defect layer
• PMN-0.38PT crystal

Acknowledgements

The authors are grateful to Prof. R.D.S. Yadava, Physics Department, BHU, for his continuous encouragement and support in many ways. One of the authors Dr Sushil Kumar also thanks the UGC, New Delhi for providing the Dr D.S. Kothari fellowship.

Additional information

Funding

This work was supported by the [project no MRP-MAJOR-ELEC-2013-12,554], UGC, New Delhi.