Multi-Tap Pixel Optical Receiver for Lower-Power Data Links
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Solution Overview
Problem
High-speed optical data links in data centers are economically inefficient due to high cost and power requirements, especially for short distances, where the cost of transmitters and receivers is relatively high compared to the low cost of fibers, leading to inefficient thermal dynamics and chip designs.
Innovation Solution
Implementing multi-tap pixels with CMOS image sensor technology in optical receivers, which operate in voltage mode and utilize multiple lower-speed fibers in parallel, reducing power consumption and cost by allowing full utilization of the optical channel and eliminating the need for high-speed transimpedance amplifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high-speed optical data links are implemented, then data transmission speed is improved, but power consumption and cost increase
Solution Approach 1:
The optical receiver is segmented into multiple independent taps, each capable of sequential integration and readout. This allows the system to process optical signals in discrete time slots, enabling lower speed fibers to be used in parallel while reducing the power consumption of individual receiver channels.
Solution Approach 2:
The multi-tap pixel operates with periodic integration and readout phases, where each tap sequentially performs integration during one time slot and readout during another. This periodic operation mode reduces the continuous power consumption compared to traditional high-speed optical receivers, while maintaining effective data transmission through time-division multiplexing.
2Speed
If high-speed optical data links are implemented, then data transmission speed is improved, but cost increases
Solution Approach 1:
By dividing the optical reception function into multiple taps that can operate sequentially, the system can use lower-speed, lower-cost fiber optic components for each tap while achieving the required overall data transmission speed through parallel processing. This segmentation allows the use of more cost-effective components without sacrificing performance.
Solution Approach 2:
The invention changes the operational parameters of the optical receiver by using voltage mode operation instead of current mode, and by implementing sequential integration-readout cycles. These parameter changes enable the use of CMOS image sensor technology, which is more cost-effective than traditional high-speed optical receiver components, while maintaining the required data transmission capabilities.
3Productivity
If multiple taps are used for sequential integration and readout, then optical channel availability is improved, but device complexity increases
Solution Approach 1:
Multiple taps are merged into a single integrated pixel structure, where each tap shares common components such as the photodetector and readout circuitry. This merging approach increases optical channel availability through time-division multiplexing while minimizing the increase in device complexity by reusing components across multiple taps rather than implementing completely separate receiver channels.
Solution Approach 2:
Each tap in the multi-tap pixel is designed with universal functionality, capable of performing both integration and readout operations. The readout circuitry serves multiple taps sequentially, and the photodetector integrates signals for multiple taps over time. This multi-functionality increases optical channel availability while keeping the device structure relatively simple compared to having dedicated circuits for each function.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces power requirements and costs, enabling efficient operation in harsh environments and achieving higher bandwidth through efficient modulation schemes, while maintaining acceptable data rates and reducing heat generation.
Implementation Method 1
a photodetector and a plurality of taps. Each tap includes a floating diffusion capacitor, a transfer gate for controlling charge flow between the photodetector and the floating diffusion capacitor
Data Source
AI summary
Examples are disclosed that relate to the use of an optical data receiver comprising a multi-tap image sensor pixel for use in optical communications. The multi-tap pixel includes a photodetector and a plurality of taps. The optical data receiver further includes a controller comprising instructions executable for controlling the multi-tap pixel to, in a first period of time, perform a first integration on the photodetector and readout charge stored on a floating diffusion capacitor of a first tap in the plurality of taps using readout circuitry of the first tap. The controller further includes instructions executable for controlling the multi-tap pixel to, in a second period of time, perform a second integration on the photodetector and readout charge stored on a floating diffusion capacitor of a second tap in the plurality of taps using readout circuitry of the second tap.