Grabka, M.Englich, F.Lancaster, D.Gawlik, W.Monro, T.Jaroszewicz, L.2013-06-242013-06-242013Proceedings of SPIE, 2013; 879497808194963480277-786X1996-756Xhttp://hdl.handle.net/2440/78456Also published as a book chapter: Fifth European Workshop on Optical Fibre Sensors / L. R. Jaroszewicz (ed.):87942MRecently we have demonstrated that conventional (free-space) Faraday rotation spectroscopy (FRS) can be successfully transitioned into optical fiber-based sensing architectures using paramagnetic gas-filled hollow-core photonic bandgap fibers (HC-PCFs)1. Our measurements revealed that due to the birefringence properties of the HC-PCFs, behavior of the fiber-optic FRS signals is substantially different compared to free-space FRS systems. Furthermore, magnetic circular dichroism tends to have much higher influence on the FRS signals than in other systems. To explain this behavior we have developed a theoretical model, and shown that close agreement with the experimental data can be achieved. In this paper we focus attention on the detailed explanation and the in-depth discussion of the model and assumptions incorporated within it. This approach can be easily extended to account for parasitic effects that take place in real-world FRS sensor systems such as imperfect polarizers or birefringent gas cell windows. © (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.en© 2013 SPIEFaraday effectFaraday rotation spectroscopyphotonic bandgap fiberparamagentic gasoptical fiber sensorConference paper002013202410.1117/12.20260590003234976000932-s2.0-8488431179217863