High-powered laser diode transmitter with integrated microlens for fast axis collimation

摘要

Abstract: The integration of small electronic packaging and miniature optics has led to a growth in opto-electronic applications. Cost and size reduction achieved by using smaller packaged systems allows for the possibility of building systems previously not possible because of cost or size constraints. Examples include low cost laser range finders for automotive adaptive cruise control and back up aid, and miniature focused laser assemblies for pollution monitoring, testing, telecommunications, and defense applications. A system is described here, which contains a near IR laser diode, a microlens, and a hybrid driving circuit, packaged within a 0.5 inch TO-8 can. The circuit enables the transmitter to produce optical pulses with pulsewidths less than 10 ns and peak pulse powers greater than 40 watts. A variable pulse repetition rate from 0.22 kHz is controlled externally. A cylindrical microlens is used to collimate the fast axis of the optical beam form the laser diode. The use of a small focal length microlens enables near collimation of the laser beam fast axis to a waist diameter of 0.004 inches. However, and cost effective for high volume production, automation of the critical alignment processes is necessary. An automation station for actively aligning a microlens in 1 to 3 minutes has been developed and is described. The system uses high precision motion controllers, machine vision, and computer automation for performing both rough alignment and fine alignment of the microlens to the laser diode. !0