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April 5-7, 2022|Santa Clara Convention Center| Santa Clara, CA
Junho Lee (Principal Electrical Engineer, Microsoft)
Location: Ballroom H
Date: Thursday, April 7
Time: 3:00 pm - 3:45 pm
Track: 06. System Co-Design: Modeling, Simulation & Measurement Validation, 01. Signal & Power Integrity for Single-Multi Die, Interposer & Packaging
Format: Technical Session
Education Level: All
Pass Type: 2-Day Pass, All Access Pass
Vault Recording: TBD
Audience Level: All
Display quality is the key element in mixed or augmented reality systems to achieve the overall system performance target. With the requirement to meet display brightness and image quality, six laser channels with fast-edge laser current were included in the co-packaged laser module. Three major SI challenges are faced in these laser channels: first, the co-packaged multiple laser channels, consisting of rigid PCBs, connectors, flex PCB and a laser module, causing high crosstalk due to special requirement of laser diode bias for each colors; second, the nonlinear input impedance of the laser module potentially causing substantial reflection without careful impedance optimization; and last, return current path discontinuities coming from different signal reference between laser drivers and laser module. These effects can significantly degrade the laser signal quality and it is critical to perform optimization to achieve the best SI.
The key takeaways from this paper will be the design optimization process showing how each channel component is managed to be optimized from package to PCB with statistical approach. As well, the modeling strategy based on measurement data for a non-linear device like a laser diode will be another thing.
The audience need to understand some technical terms like return current path, trace impedance, signal reflection, insertion/return losses, crosstalk and general understanding for signal reference design for signal integrity.