Solid immersion lenses in planar waveguides

In this paper, solid immersion lenses (SILs) in silicon-based planar waveguides are designed and fabricated. The lenses are designed by the ray-tracing method to optimize the lens profiles. Experimental results show that a minimum spot size of 0.77 /spl mu/m can be obtained as the calculation prediction. Hence, the SILs combined with other optical components in planar waveguides can alleviate the alignment, tilt, and packaging problems in free-space optical systems.