The LD output beam of 980nm wavelength band is generally elliptical, and the ratio of the long and short axis of the ellipse is proportional to the output power. Generally, the ratio is 3~5. The high-power LD can be greater than 10, and the highest can reach more than 50. Obviously such a beam is difficult to be coupled into the fiber.

In order to adapt to the LD output beam shape, a wedge lensed fiber can be used. The two large wedge surfaces correspond to the direction with a larger LD divergence angle, so that the coupling efficiency can be increased. Ordinary wedge lensed fiber needs to do anti-reflection coating on the end surface to minimize the reflected light, while the Angle wedge lensed fiber has a special geometric shape, so that the lensed fiber and the LD form a refraction angle without affecting the optical path transmission, avoiding the influence of the reflected light on the LD, and also eliminating the noise interference caused by the reflected light.

Compared with the anti-reflection coating process of ordinary wedge lensed fiber, the AR coating cost is saved, and the instability caused by poor controllability of the coating process are reduced as well.