Polymeric power splitters for multiplexing optical biosensors

Aiming efficient multiple simultaneous detection, two different designs of 1 x N power splitters for single source feeding of an N-array biosensors operating at 1550 nm are here proposed and thoroughly compared and discussed. Taking into account the need for micro guiding structures, simpler and cheaper manufacturing processes, SU-8 polymer is adopted as the core material. Our first proposal is based on a cascade arranged directional couplers (DC) with a footprint of 4.2 x 0.42 mm(2), uniform power division and losses of 0.54 dB. The second proposal is based on a multimode interference device (MMI) exhibiting a compact footprint of 1.25 x 0.23 mm(2), highly uniform power division and significant low losses of 0.16 dB.