“Design of CWDM multiplexers based on series coupled ring resonators: Analysis and potential of MEMS technologies“

New designs for a 1 times 4 and a 1 times 8 CWDM multiplexers based on cascaded groups of series coupled ring resonators are presented. Compared to other integrated optical alternatives such as MMI phasars, cascaded Mach-Zehnder interferometers and cascaded AWG, the proposed circuits offer superior performance in their very sharp roll-off factor that exceeds 0.75, their reduced crosstalk level that lies below -80 dB and their negligible insertion loss for the 1 times 4 design. For the 1 times 8 design, the worst case insertion loss is 4 dB. However, the performances obtained exhibit passband ripples in the order of 5 dB, and besides, they are not very tolerant to fabrication errors. Being designed for SOI technology, the proposed circuits are compact as the circuit areas are 130 times 130 mum² and 90 times 150 mum² for the 1 times 4 and 1 times 8 designs, respectively. They also have a high potential for MEMS tunability.