We have designed and integrated a high density micro-ring resonator and photonic crystal waveguide array for wavelength division multiplexing (WDM) microsystem applications. First, we designed and optimized micro-ring resonators. Using the non-unitary transfer matrix method (NU-TM), we have been able to analyze the transfer characteristics of the micro-ring and micro-racetrack resonator system. The track-length dependence, which is not obvious in the unitary transfer method (U-TM) analysis, is clearly found in the NU-TM analysis. By optimizing the WDM filter characteristics such as FSR (Free Spectral Range) and cross-talk, we have found the optimal dimensions, such as length, of the racetrack resonator. And then for improving the WDM filter characteristics of microring resonator, we have designed bent photonic crystal waveguide. Integrating microring resonator with bent photonic crystal waveguide can offer additional functions such as band pass filtering function.
We present a new approach in the design of a photonic crystal bandpass filter by using waveguide bending. The bandpass filter was designed by introducing two bends with the modified geometry into the both ends of a photonic crystal waveguide. We show that such a filter exhibits step-like spectral profile in the range of 1500-1600 nm, with a maximum transmission of 100%. In contrast to the other designs proposed, the present one does not involve either insertion of small defects or control of cavity-lengths.