Optical Sciences

Biomolecules and nanostructures

The Optical Sciences group studies the interaction of light and matter at the nanoscale. We do this by exploring ways to shape light and its environment. It's what we call active and passive control. Our current focus is on the interaction of light with biomolecules and nanostructures. We are part of Twente University's Department of Science and Technology and member of the MESA+ institute.
We participate in the EU-COST actions MP1102: Coherent Raman microscopy (MicroCor) and CM1202: Supramolecular photocatalytic water splitting (PERSPECT-H2O)


A Low-Loss and Broadband MMI-Based Multi/Demultiplexer in Si3N4 / SiO2 Technology

(full pdf)

Jinfeng Mu, Sergio A. Vázquez-Córdova, Mustafa Akin Sefunc, Yean-Sheng Yong, and Sonia M. García-Blanco
Journal of Lightwave Technology
vol 34, issue 15, aug. 1, 2016

A low-loss and broadband multimode interference (MMI)-based wavelength multi/demultiplexer in Si3N4 / SiO2 technology for erbium-doped lasing and amplifying applications is presented. The structural parameters of a 2 x 1 Si3N4 MMI multi/demultiplexer are optimized to minimize losses. The design and analysis of the MMI multi/demultiplexer are carried out using a hybrid approach, which combines a modified effective index method, the 2D film mode matching method, and the 2D beam propagation method, with lower impact in the computing requirements and simulation time than 3D methods. Simulated total losses of 0.19 and 0.23 dB at 980 and 1550 nm, respectively were obtained for the optimized MMI multi/demultiplexer. The measurements of our fabricated couplers, with 110 nm thick Si3N4 layer, show good agreement with our design. As multiplexers, the average losses of the MMI were measured to be 0.4 +/-0.3 dB for both 976 and 1550 nm wavelengths, and less than 1 dB across the whole C-band. As demultiplexers, the measured average extinction ratio of the fabricated MMI was found to be 21.4 +/-1.2 and 26.3 +/-0.8 dB for pump and signal wavelengths, respectively.
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