Focusing characteristics of a wide-striped laser diode integrated with a microlens

We developed a wide-striped laser diode integrated with a microlens that provides good focusing characteristics through a small focusing spot. We calculated and demonstrated that a 60-/spl mu/m-wide core and a 1.9-/spl mu/m-high ridge is the best structure for fundamental index-guiding mode oscillation of a wide-striped laser diode. We integrated a wide-striped laser diode with the developed microlens in the Fresnel diffraction held, and demonstrated that a device with a 60-/spl mu/m-wide core has a minimum focusing spot width of 2.0 /spl mu/m in the horizontal direction. Also, we estimated the wavefront in the Fresnel diffraction field from the working distance error of a lens designed for a collimated incident beam, and showed that the working distance error, focusing spot width, and sidelobe can be improved by this estimated wavefront.<
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