Design of a Narrow Band Filter Based on a Photonic Crystal Cavity for CO2 Sensing Application

Abstract

This paper investigates the use of a miniaturized filter based on a triangular lattice of holes in a photonic crystal (PhC) slab. The plane wave expansion method (PWE) and finite-difference time-domain (FDTD) techniques were utilized to analyze the dispersion and transmission spectrum, as well as the quality factor and free spectral range (FSR) of the filter. A 3D simulation has demonstrated that for the designed filter, an FSR of more than 550 nm and a quality factor of 873 can be attained by adiabatically coupling light from a slab waveguide into a PhC waveguide. This work designs a filter structure that is implemented into the waveguide and is suitable for a fully integrated sensor. The small size of the device provides a strong potential for the realization of large arrays of independent filters on a single chip. The fully integrated character of this filter has further advantages such as reducing power loss in coupling light from sources to filters and also from filters to waveguides. The ease of fabrication is another benefit of completely integrating the filter.

A High Selective and Q Factor 4-Channel All Optical Demultiplexer: Numerical and Analytical Evaluation

“…Separate from T-shaped waveguide, Lbend and straight waveguides were described that are very practical in multigate functional design [11]. Because these structures consist of photonic bandgap (PBG) in their structures, have unique advantages as high operation, compact footprint and low power losses in different applications such as switches, [12], filters [13][14], optical splitters [15], waveguides [16] and de-multiplexers [17]. Today, utilization of PCs based devices for design of optical devices has been increased including OR, NOR [18][19][20], AND [21], NAND [22], XOR [23], and XNOR [24] logic gates, and all-optical full adder [25].…”