Raised Cosine Pulse Shaping for 100 Gbps Short-Reach Links
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Solution Overview
Problem
Current short-reach optical communication links using VCSELs and DFB lasers face challenges in achieving 100 Gbps data rates due to bandwidth limitations, requiring techniques to cost-effectively increase data throughput while maintaining low cost and low power consumption.
Innovation Solution
The implementation of Raised Cosine (RC) pulse shaping, transmitter-based pre-emphasis, and receiver-based equalization, which includes pulse shaping, filtering, timing recovery, and equalization, to optimize signal transmission and reception over existing infrastructures with bandwidths less than 50 GHz, enabling data rates of at least 100 Gbps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If VCSELs with low bandwidth (low 20 GHz range) are used, then cost and power consumption are reduced, but data throughput cannot reach 100 Gbps
Solution Approach 1:
The patent applies transmitter-based pre-emphasis and receiver-based equalization as preliminary actions to compensate for bandwidth limitations before data transmission. The pre-emphasis technique pre-distorts the signal to counteract expected channel losses, while equalization restores the signal spectrum, enabling 100 Gbps throughput with lower bandwidth VCSELs
Solution Approach 2:
The patent changes signaling parameters by implementing PAM-4 modulation instead of traditional NRZ, and applies digital signal processing techniques including pulse shaping and timing recovery. These parameter changes allow the system to achieve higher data rates by optimizing the electrical and optical signal characteristics to match the available bandwidth
2Productivity
If component bandwidth is increased to 50 GHz to support 100 Gbps, then data throughput increases, but cost and power consumption increase
Solution Approach 1:
The patent replaces the need for high-bandwidth hardware components with digital signal processing algorithms. Instead of relying on hardware with 50 GHz bandwidth, the system uses software-based pre-emphasis, equalization, and pulse shaping techniques to achieve the same effect, reducing hardware complexity and cost
3Quantity of substance
If PAM-4 modulation with Reed-Solomon FEC is used, then fiber count is reduced, but implementation complexity increases
Solution Approach 1:
The patent implements self-service through automated training sequences and adaptive equalization algorithms that automatically adjust to channel conditions. The system includes built-in calibration procedures that enable the transceiver to optimize its performance without manual intervention, reducing the operational complexity of PAM-4 modulation
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 effectively increases data throughput in short-reach optical communication links by band-limiting signal spectra, supporting higher data rates with lower bandwidth components, and minimizing out-of-band noise, thus overcoming bandwidth constraints.
Implementation Method 1
converting, by the transmitter, the equalized and pulse shaped first electronic signal into an optical signal
Implementation Method 2
converting, at the receiver, the optical signal into a second electronic signal
Data Source
AI summary
Systems and methods are provided for enabling lower-bandwidth hardware components to support higher data rates. In particular, aspects of the disclosed systems and methods use Raised Cosine pulse shaping in short-reach links to band limit the signal spectra and thereby enable existing, such lower-bandwidth components to support higher data rates.