Design of 1-to-2-line all-optical decoder based on MMI phase shifter

Design of an all-optical 1:2 decoder has been proposed based on a holes-in-slab photonic crystal structure. Operation of the device depends on optical interferometry of an input and a bias signal. In order to achieve wavelength independent optical interference, a multimode Interference (MMI) based pi-phase shifter is proposed, analysed and integrated within the design of the decoder. Dispersion diagram of the MMI pi-phase shifter depicts almost equal slope of two propagation bands for a long range of wavelengths, which ensures its wavelength insensitive phase-shift operation. Finite Difference Time Domain (FDTD) simulation also confirms the same. Further, several simulations and corresponding analyses for evaluating different performances of the decoder have also been performed. These analyses exhibit the successful decoding operation of the device. The decoder performance has also been studied under the excitation of pulsating input and bias. This study concludes that the device is able to process a bit-rate as-high-as 2.94 Tbps. This small footprint (similar to 243 mu m(2)) device also offers an excellent contrast ratio of the order of 20 dB. Hence, it is expected that the device would be a potential candidate for implementing complex circuitries in photonic integrated circuits.