Coupling efficiency for laser beam radiation of high quality
A coupling efficiency of > 80% is achieved when coupling laser sources with rotationally symmetric beams of high quality (M2 < 1.05) and no astigmatism.
Loss contributions are mainly through:
- Transmission loss in the laser beam coupler ~ 1%
- Imaging aberration, stray loss and beam distortion (M2 > 1) ~ 8%
- Fresnel reflection loss at fiber end faces ~ 8%