We have designed a four-channel wavelength demultiplexer based on photonic crystal ring resonators (PCRR), which can be used for photonic integrated circuits. Dropping efficiency and Q factor of single improved ring are 100% and 650, respectively. In order to achieve the structure of demultiplexer, three improved rings have been used, that every ring has an individual inner rod radius; it means that each ring has a varying resonant wavelength. By changing the radius of inner rods, various wavelengths can be chosen, therefore this device is tunable. The results of simulation using finite-difference time-domain (FDTD) method in our proposed structure reveals an average transmitted power higher than 90% for each output port. Channel spacing is about 7.5 nm and bandwidth for each individual channel is about 2.8 nm. The mean value of the crosstalk between output channels is about −27.11 dB. The area of the proposed structure is about 315 μm2.
©2014 by Walter de Gruyter Berlin/Boston