Development of compact mid-infrared fibre laser using 2D-nanomaterials and side-polished fibre

In the recent past, the field of photonics has opened new horizons and allowed the development of compact photonic devices to replace larger optical devices. This thesis presents a step towards building a compact all fibre mid-infrared laser, using 2D nanomaterials. The experimental setup used erbium-doped double clad ZBLAN fibre as the laser cavity, and an external confocal setup was used to pass the signal through a 2D nanomaterial. The results demonstrated stable mode-locking in the mid-infrared region when we used MXene and PtSe2 2D nanomaterials as saturable absorbers, while SESAM showed Q-switched mode-locking due to the high band gap energy. The signal to noise ratio of the mode-locked pulses was evaluated against the thickness of the saturable absorber being pasted on the CaF2 substrate. The results showed an improved SNR, with the increase of the number of layers of saturable absorber resulting in improved mode-locked pulses. Further, the experimental research was extended so as to increase the compactness of the laser through removing the confocal setup and pasting SA on a side polished fibre. For this purpose, we worked to find a reliable and consistent method to side-polish a fibre to access the evanescent field. Custom 3D models were built to precisely side polish a ZBLAN fibre to achieve a smooth surface for nanomaterial printing.