Pressure-Induced Long-Period Gratings in Multi-Core Fibers

In this work, we experimentally demonstrate pressure-induced long-period gratings (LPGs) in a 4-core optical fiber through the mechanical pressing method using a 3D printed grooved plate. The plate was fabricated with a consumer grade 3D printer and presented a period of about 650 µm. We observed that the LPG transmission spectrum of each core, and the power transfer between them, changed by rotating the fiber. Power transfer of about –13 dB (5%) was achieved between two cores at ∼1430 nm, near their LPGs’ resonant regions. Results show that it is possible to temporarily induce LPGs into a multi-core fiber (MCF) and promote wavelength-selective coupling between the MCF cores, paving the way for their integration in MCF optical transmission systems.