DWDM Forwarded Clocking with ILO Jitter Filtering
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Solution Overview
Problem
High-speed data transmission systems face challenges with correlated and uncorrelated jitter, which affect the performance and reliability of transceivers, especially in dense wavelength division multiplexing (DWDM) systems, due to synchronization errors, noise, and environmental factors, making it difficult to align transmitter and receiver components effectively.
Innovation Solution
Implementing a flexible forwarded clocking mechanism in DWDM systems that allows the forwarded clock to be transmitted on any wavelength, received without excessive heating, and distributed with jitter filtering, while tracking correlated jitter to improve overall performance. This includes phase-locked loops, backchannels for communication, and injection-locked oscillators to synchronize clock distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed pairing of transmitter and receiver lanes is used, then the system is simpler to implement, but the components may become misaligned over time due to aging and environmental factors
Solution Approach 1:
The patent implements dynamic lane assignment where the receiver can identify and adapt to the optimal transmitter lane for receiving the forwarded clock signal. Instead of fixed pairings, the system allows flexible assignment of clock lanes to different data lanes based on actual performance and environmental conditions, resolving the contradiction between simplicity and reliability.
Solution Approach 2:
The system incorporates feedback mechanisms where the receiver identifies which transmitter lane is providing the forwarded clock signal and communicates this information back. This feedback allows the system to adapt to component drift and aging by dynamically adjusting lane assignments to maintain optimal alignment between transmitter and receiver components.
2Stability of the object's composition
If the forwarded clock is transmitted on a specific wavelength, then the clock signal is stable, but the receiver may require excessive heating to detect the signal
Solution Approach 1:
The patent allows the forwarded clock to be transmitted on any wavelength rather than a fixed wavelength. The receiver can identify and tune to the appropriate wavelength carrying the clock signal, avoiding the need for excessive heating to detect weak signals at fixed wavelengths. This parameter flexibility resolves the contradiction between signal stability and receiver temperature requirements.
3Adaptability or versatility
If the forwarded clock is transmitted on any wavelength, then the system is more flexible, but it becomes challenging to identify the clock lane at startup
Solution Approach 1:
The patent implements preliminary identification mechanisms where the receiver attempts to identify the forwarded clock lane during startup before normal operation begins. This preliminary action allows the system to establish the correct wavelength assignment early, resolving the contradiction between wavelength flexibility and identification difficulty by addressing the identification challenge before system operation commences.
4Device complexity
If the TIA is used to receive the clock signal, then the receiver is simpler, but uncorrelated jitter from thermal noise contaminates the forwarded clock
Solution Approach 1:
The patent extracts the clock signal from the data signal path by using a dedicated forwarded clock lane that is separate from the data-carrying lanes. This extraction allows the clock signal to be received and processed separately, enabling the use of simpler receivers while maintaining clock purity by isolating it from the noisy data transmission path that would otherwise contaminate it with thermal noise.
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
The solution reduces uncorrelated jitter and aligns receiver lanes effectively, enhancing the reliability and performance of high-speed data transmission by minimizing timing errors and maintaining synchronization across DWDM systems.
Implementation Method 1
an injection-locked oscillator (ILO) that synchronizes to a forwarded clock from the transmitter
Implementation Method 2
This may include phase-locked loops, backchannels for communication, and injection-locked oscillators to synchronize clock distribution
Data Source
AI summary
A dense wave division multiplex (DWDM) receiver includes receiver lanes each configured to detect signals encoded in a different electromagnetic frequency band. The DWDM receiver applies a clock signal received on a variable one of the receiver lanes to lock a frequency of an injection locked oscillator (ILO) of a clock distribution network, and receiver lanes that are configured to receive data signals generate resonance on the clock distribution network. The resonant signal from the clock distribution network is applied to sample the received data signals.