A multi-segment optical component applied to increase signal-to-noise ratio includes a base, a central lens portion, an isolating lens portion and a collecting lens portion. The central lens portion is disposed on center of the base. The isolating lens portion is disposed by a side of the central lens portion, and the collecting lens portion is disposed by the other side of the central lens portion opposite to the isolating lens portion. At least one of the isolating lens portion and the collecting lens portion has a curvature radius different from a curvature radius of the central lens portion, and the curvature radius of the isolating lens portion can be similar to or different from the curvature radius of the collecting lens portion. The central lens portion has a central axle which does not overlap a curvature center of one of the isolating lens portion and the collecting lens portion.
