Characteristics of suspended-core fiber interferometer: Modal analysis

Suspended-core fiber (SCF) represents a promising class of microstructured optical fibers for sensing applications. In this work, we present a thorough modal analysis of the SCF based modal interferometer which is constructed by splicing 50 mm of SCF to single mode fiber at both ends. The measured transmission spectrum exhibits three-beam interference-like spectrum. In the modal analysis, we investigate the intermodal coupling between the fundamental and higher-order modes, as well as the coupling between the orthogonal polarizations in the fundamental modes. In comparison with the typical two-mode interferences in photonic crystal fiber interferometers, the measured spectrum of SCF interferometer has distinctively sharper spectrum for high resolution and high dynamic range application.