Optical performance of a diode laser circularizer microlens

The output from a laser diode is not circularly symmetric, the output divergence in one axis is much greater than that in the transverse axis. NEMS Optical has developed a laser diode circularizer(1) that can take the elliptical output beam from a laser diode and circularize the beam. Due to it's operating principle, it has a major advantage in that precise alignment is not required, making assembly operations much simpler and faster. Due to the ability to manufacture this device in wafer scale, it can be economically manufactured. We report here the results of a series of optical performance measurements, including wavefront phase and Strehl ratio. Designed for a wavelength of 650nm, it has less than 0.05 waves of wavefront error, Strehl ratios as high as 98%, efficiency of 89%, and circularity >0.95. The lenses have low aberrations and high throughput with a circular cross section. These lenses are ideal for use in applications such as optical data storage, fiber coupling, and any application in which degraded performance is due to an elliptical beam.