Laser Power Modulation of Fiber Coated with Multilayer-Graphene Based on Lithium Intercalation Method

Dynamic manipulation of light in optical fibers has attracted extensive interest due to its compatibility with various fiber-optic systems. The integration of two-dimensional (2D) materials on the surface of optical fibers is an effective method to manipulate light beams. However, it is still a huge challenge to acquire dynamic modulation for light signals in fiber. In this work, we develop electrically manipulable in-line multilayer graphene (MLG) devices by integrating a graphene-based lithium-ion (Li-ion) battery on a side-polished fiber. Through charge and discharge processes with a current of 400 µA, the output power of a 1550 nm laser can be cyclically tuned in the range of ~120 and ~240 µW with a response time of about 1.8 min. After 100 cycles of testing, the modulation power of the laser system remains nearly unchanged, exhibiting good stability. The optical modification of MLG is due to the shift of Fermi energy (Ef), which results from charge transfer between Li and graphene layers. Therefore, the light in the fiber can be modulated due to the change in the optical absorbance of MLG. Our findings imply potential value in fabricating fiber-intergraded 2D intercalation materials with high tunability.