Executive Summary : | Objective: Demonstration of an all-fiber based prototype pulsed fiber laser sources for additive manufacturing and precision material processing , Operating Wavelength, Mode of Operation, Modulation frequency in QCW mode, Pulse energy Summary: In the proposal, it is proposed to demonstrate a QCW Yb-fiber laser operating at the near-infrared (NIR) regime at 1070 nm has unique properties such as high pulse energy with high peak power, high average power, and very good beam quality. These QCW Ytterbium (Yb) Fiber lasers can operate with variable pulse length in pulsed mode at KW level peak power, as well as in continuous-wave (CW) mode at high average power. High peak power provides advanced processing capabilities for faster material processing, increased output quality, repeatability and waste reduction. This translates into high-throughput precision machining, 3D printing to battery manufacturing, spot welding and joining of dissimilar metals. These QCW Yb-fiber lasers are now rapidly displacing the long-established Nd:YAG flashlamp pumped laser technology. Another objective of the proposal is to demonstrate ultrafast fiber laser source. In the proposed work, Yb-doped large-mode area (LMA) fibers will be used as gain medium. ‘Seed laser’ of pulse-width of the sub pico-second order will be generated using fiber pigtailed semiconductor saturable absorber mirror (SESAM). The pulse will be stretched upto few hundreds of ps to ns using specialty fibers and then it will be amplified to high power using CPA technique to avoid nonlinearity. In the amplifier stage, LMA double-clad Yb doped fiber will be used to amplify the laser. After amplification, the pulse will be compressed to few hundreds of fs using specially designed photonic crystal fiber (PCF). The basic principle of chirped pulse application (CPA) technique is shown schematically below A prototype module of the proposed fiber laser source be demonstrated for material processing like writing of fiber Bragg grating in the silica fiber, writing channel waveguide in the glass substrate. It has very good application for making flat panel display. |
