Abstract: A device for focusing light from a laser transmitter is provided. A focusing lens is coupled to a inner portion of a disc shaped diaphragm and the outer portion of the diaphragm is coupled to a mounting assembly. The diaphragm is flexible along the optical axis of the focusing lens but rigid along the transverse plane of the lens. The focus point of a laser is changed by flexing the diaphragm in a direction parallel to the optical axis with a diaphragm flexing device. The position of the lens along the optical axis changes as the diaphragm is flexed, thereby changing the focus point of the laser. The lens does not move laterally so that there is no tilting of the laser beam off the optical axis.