Design and fabrication of thin film optical filters to replace fiber Bragg grating in Yb-doped fiber laser

Thin film optical filters were designed and fabricated on the end-side of the fiber as the end pumping and out coupler devices to replace the fiber Bragg grating in Yb-doped fiber laser system. It was found that the average transmittance of the end pumping device in the laser pumping wavelength (900–985 nm) is around 95.2%, and the average reflectance in the laser irradiation wavelength (1065–1085 nm) is 99.72%. The average reflectance of the out coupler device is 99.7% (900–1035 nm), and the average transmittance is 20% (1065–1085 nm), respectively.