A self-aligned optical subassembly for multi-mode devices

A completely self-aligned optical sub-assembly is described that meets the optical alignment tolerances needed for low-loss LED and PIN photodiode OSA's. Solder reflow aligns the optical device (LED or PIN photodiode) to a silicon "header," which is mechanically aligned to a silicon fiber stub with fiducial cavities and alignment spheres. This assembly is in turn mounted in a plastic ferrule. Devices made using this alignment scheme have demonstrated losses as low as 0.5 dB relative to a butt-coupled fiber measurement.<
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