For over 20 years, we have been producing fiber optical collimators according to customer specifications using our unique fiber end lens and V-groove technologies. Unlike an ideal optical collimator that is characterized as a beam propagating within a divergence angle to the infinity distance. A practical collimating beam profile is shown in the graph, which is characterized by its beam waist size, working distance, and off-axis tilting angle. We have special instruments to precisely measure these parameters during fabrication. Therefore, due to cost and size constraints, a practical fiber-optical collimator is optimized within a working distance range. For multimode transmission, the collimator performance intrinsically depends on the laser mode field distribution. To be consistent with customer expectations, a similar profile laser is required during the fabrication and tests.