Low-loss all-fiber inline polarizer based on graphene oxide and nanogold film composite structure

Abstract

The all-fiber inline polarizer (AFILP) is gaining prominence in fiber optic sensing and laser technologies due to its compact design and strong resistance to interference. However, its further development is hindered by the issue of optical loss. To address this challenge, we propose a low-loss AFILP that incorporates a composite structure of graphene oxide and nanogold film, applied to D-shaped fibers polished to varying depths. Experimental results demonstrate that the polarization extinction ratio (PER) and the insertion loss (IL) of the transmitted polarization in a nanogold-coated D-shaped fiber are positively correlated with the distance from the fiber core at specific polishing depths. For instance, at a distance of 4 µm from the fiber core center, the PER reached 38.82 dB, while the IL was 2.831 dB. Notably, at the same polishing depth, the all-fiber polarizer incorporating a composite structure of graphene oxide and nanogold film exhibited a PER of 36.65 dB, along with an exceptionally low IL of 0.2 dB, corresponding to the loss of the transmitted polarization.These findings suggest that the composite structure effectively reduces insertion loss while maintaining high PER, offering significant potential for enhancing AFILP performance. Additionally, the graphene oxide layer was formed by drying a graphene oxide dispersion, providing a cost-effective and straightforward alternative to traditional graphene coating methods.