Optical Assembly Passive Alignment OED Mounting
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Solution Overview
Problem
Surface emitting opto-electric devices, such as VCSELs and PIN photodiodes, face challenges in aligning their photosensitive surfaces with optical fibers due to the need for active alignment and reflective surfaces, which increases insertion loss and manufacturing complexity.
Innovation Solution
Mounting the OEDs perpendicular to the substrate with precise mechanical features created through photolithography for passive alignment, allowing direct coupling without additional light direction changes, and using alignment elements like V-grooves or edges to ensure accurate positioning along multiple axes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If surface emitting OEDs are mounted on a substrate with reflective surfaces to enable passive alignment, then alignment precision is improved, but optical insertion loss increases due to intrinsic losses at each optical surface
Solution Approach 1:
The patent removes the reflective surface element from the optical path entirely. By mounting the OED perpendicular to the substrate with its optical axis parallel to the substrate, the system eliminates the need for light to reflect off a surface, thereby removing the source of intrinsic optical losses while maintaining passive alignment capability through mechanical features like V-grooves or registration marks.
Solution Approach 2:
Instead of mounting the OED parallel to the substrate and using a reflective surface to redirect light (conventional approach), the patent inverts the mounting orientation: the OED is mounted perpendicular to the substrate with the optical axis parallel to the substrate. This inversion eliminates the reflective surface requirement and reduces optical losses.
2Ease of manufacture
If surface emitting OEDs are mounted parallel to the substrate with reflective surfaces, then passive alignment is enabled, but device complexity increases due to additional alignment features and reflective surfaces
Solution Approach 1:
The patent extracts and removes the reflective surface component from the system. By changing the OED mounting orientation to perpendicular with optical axis parallel to the substrate, the system achieves passive alignment through simpler mechanical features on the substrate (such as V-grooves or registration marks) without requiring complex reflective surfaces or additional alignment elements.
3Manufacturing precision
If active alignment is used to align OEDs with optical fibers, then alignment precision is improved, but manufacturing speed and productivity decrease
Solution Approach 1:
The patent incorporates alignment features (such as V-grooves, registration marks, or mechanical stops) directly into the substrate during manufacturing, before the OEDs are mounted. This preliminary preparation of alignment references enables passive alignment during assembly, achieving both high precision and high manufacturing speed without requiring time-consuming active alignment procedures.
Data Source
AI summary
An optical assembly having x, y and z axes and comprising: (a) a first substrate having a planar surface, a first wall adjacent and substantially perpendicular to the planar surface, a first register surface adjacent the first wall, at least one foundation to receive an optical element having a first optical axis at least partially along the z axis; (b) an opto-electrical device (OED) having a top surface, an active area on the top surface having a second optical axis normal to the top surface, and a first alignment element defined on the top surface, the OED mounted to the first wall such that the first alignment element contacts the first register surface to position the OED on the first substrate along at least one of the x or y axes with the second optical axis parallel to the planar surface.