The LBTEK zoom fiber collimator adopts an achromatic design, with three optional anti-reflection coatings: 400-650 nm, 650-1050 nm, and 1050-1650 nm. The focal length adjustment range is from 6 mm to 18 mm, maintaining beam collimation throughout the focal length adjustment process. In addition to adjusting the focal length, it also allows for precise adjustment of the beam divergence angle. The beam can be focused at any position between the maximum infinity (see technical specifications for details) and the closest focusing distance of 0.3 m, enabling free-space laser beams to couple into optical fibers with maximum coupling efficiency. The zoom fiber collimator is based on an air-spaced lens design, resulting in better beam quality compared to fixed aspheric fiber collimators. The low-aberration air-spaced design achieves an M2 factor closer to 1 (Gaussian beam) and smaller wavefront error.