Polarization Processing Devices

The ability to manipulate and exploit the polarization of light underpins many high performance communications and sensing circuits. We develop a broad range of components and techniques which can be implemented within photonic integrated circuits, focusing particularly on technologies which can be implemented within the generic photonic integration roadmap. A full set of polarization manipulating devices, including polarization converters, polarization splitters and combiners, polarization scramblers, polarization controllers and polarization filters has been designed and realized in the COBRA process and the Fraunhofer HHI foundry-process.

High polarization conversion and very low loss has been achieved with this device, due to a new technological approach and a patented two section design. The converter consists of two right trapezoidal sections with wet-etched angled sidewalls. The converters show a greatly improved tolerance to variations of the fabrication, an averaged efficiency of polarization conversion of 99.8% and a loss of about 0.7 dB at a wavelength of 1.535 μm.

Publications
Dzibrou, D.O., Tol, J.J.G.M. van der & Smit, M.K. (2013). Tolerant polarization converter for InGaAsP-InP photonic integrated circuits. Optics Letters, 38(18), 3482-3484.
Dzibrou, D.O., Tol, J.J.G.M. van der & Smit, M.K. (2013). Improved fabrication process of low-loss and efficient polarization converters in InP-based photonic integrated circuits. Optics Letters, 38(7), 1061-1063.
Pello, J., Tol, J.J.G.M. van der, Keyvaninia, S., Veldhoven, P.J. van, Ambrosius, H.P.M.M., Roelkens, G.C. & Smit, M.K. (2012). High-efficiency ultrasmall polarization converter in InP membrane. Optics Letters, 37(17), 3711-3713.
Tol, J.J.G.M. van der, Felicetti, M. & Smit, M.K. (2012). Increasing tolerance in passive integrated optical polarization converters. Journal of Lightwave Technology, 30(17), 2884-2889.
Augustin, L.M., Hanfoug, R., Tol, J.J.G.M. van der, Laat, W.J.M. de & Smit, S.G. (2007). A compact integrated polarization splitter/converter in InGaAsP/InP. IEEE Photonics Technology Letters, 19(17), 1286-1288.
Augustin, L.M., Tol, J.J.G.M. van der, Hanfoug, R., Laat, W.J.M. de, Moosdijk, M.J.E. van de, Dijk, P.W.L. van, Oei, Y.S. & Smit, M.K. (2007). A single etch-step fabrication-tolerant polarization splitter. Journal of Lightwave Technology, 25(3), 740-746.
Augustin, L.M., Tol, J.J.G.M. van der, Geluk, E.J. & Smit, M.K. (2007). Short polarization converter optimized for active-passive integration in InGaAsP/InP. IEEE Photonics Technology Letters, 19(20), 1673-1673.