Optical Emitter Package Low-Inductance Interconnects
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Solution Overview
Problem
Optical emitter packages, particularly in LIDAR systems, face limitations due to high inductance in electrical interconnects, which restricts high-frequency switching and power output, leading to increased pulse durations and reduced performance.
Innovation Solution
The implementation of wide conductive traces and interconnect structures, such as ribbon interconnects or flexible substrates, to reduce inductance between the optical emitter die, switching die, and energy storage device, enabling faster switching speeds and higher power output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional electrical interconnects are used in optical emitter packages, then the package structure is simple and easy to manufacture, but the inductance is high which limits switching frequency and power output
Solution Approach 1:
The interconnect structure is segmented into multiple functional layers: a first interconnect layer for low-inductance current delivery, a second interconnect layer for signal routing, and a ground layer for reference potential. This segmentation allows each layer to be optimized for its specific function, reducing overall inductance while maintaining manufacturability through standard PCB fabrication techniques.
Solution Approach 2:
The patent transitions from traditional planar interconnects to a three-dimensional stacked architecture where interconnect layers are vertically arranged. The optical emitter die is mounted with its active surface facing the first interconnect layer, creating a vertical current path that minimizes loop area and inductance. This dimensional change enables faster switching frequencies while keeping the package footprint compact.
2Power
If high power output is achieved in optical emitter packages, then the performance of LIDAR systems is improved, but the pulse duration increases and switching speed decreases
Solution Approach 1:
The patent merges the optical emitter die, driving electronics, and energy storage components into a single integrated package. The driving electronics are positioned in direct electrical contact with the optical emitter die through low-inductance interconnects, and the energy storage capacitor is integrated within the package. This merging reduces external parasitic inductance and enables rapid charge-discharge cycles, achieving high power output with short pulse durations suitable for high-performance LIDAR systems.
3Speed
If high frequency switching is implemented to improve laser performance, then the switching speed increases, but the inductance of electrical interconnects becomes a limiting factor
Solution Approach 1:
The patent applies different interconnect characteristics to different locations within the package. The first interconnect layer uses wide-trace geometry and short current paths specifically at the optical emitter die interface to minimize inductance where high-frequency switching occurs. Other areas of the package use standard interconnect designs. This localized optimization ensures reliable high-frequency switching performance where needed while maintaining overall package reliability.
Data Source
AI summary
An optical emitter package is disclosed. The optical emitter package can include a carrier, a switching die, and an optical emitter die mounted to the carrier. The optical emitter die can be directly electrically and mechanically connected to the carrier with a conductive adhesive. An energy storage device can be mounted to the carrier. The energy storage device can be directly electrically and mechanically connected to the carrier with a second conductive adhesive. The carrier can provide electrical communication between the switching die, the optical emitter die, and the energy storage device.