Variable optical attenuators (VOA) and optical switches are employed for remote optical power control and the distribution of optical signals in fiber-optic networks. Scientists at the Fraunhofer IPMS have developed broadband, bi-directional, fast (sub-microsecond) and reliable VOAs and optical switches based on a unique, innovative concept of electro-optical waveguides with a liquid crystal core integrated on a silicon backplane. These VOAs and switches can be conveniently programmed by directly applying voltages on individually addressable electrodes. In a novel device design concept, the electric field distribution – used to shape the waveguide – can be tuned to allow the propagation of either one or both linear polarization modes. The devices – developed for polarization maintaining and polarization insensitive applications – feature low insertion loss thanks to on-chip mode-matching couplers, low PDL and a continuously tunable wide optical attenuation range.
Interrogation instruments for fiber optic sensors can greatly benefit from the Fraunhofer IPMS optical power control and switching solution in MHz range. Furthermore, these devices can be used in DWDM applications for channel selection, power manipulation and stabilization.
Part of the development has been carried out within the project Electro-Optical Waveguides based on Liquid Crystals for Integrated Optical Switching (EOF-IOS), contract No. 13N12442, funded by the German Federal Ministry of Education and Research in the program Photonic Research in Germany and the research initiative Wissenschaftliche Vorprojekte (WiVorPro).
OFC Exposition visitors can find the Fraunhofer IPMS exhibition at Booth 2638. In addition, Dr. F. Costache will present the latest research results at the OFC Conference. The talk entitled “Polarization Insensitive Variable Optical Attenuator Based on Field Induced Waveguides with a Liquid Crystal Core” is scheduled as part of the “Advanced Photonic Integration Platforms” session to be held on March 25, 2015 from 3:30 PM to 5:30 PM.