Voltage Controlled SerDes Feedback Circuit for Power Optimization
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Solution Overview
Problem
Optical communication systems face inefficiencies in power consumption and signal quality due to over-estimation of voltage amplitude and power levels, leading to excessive electrical power usage and costly cooling requirements, especially in high Gb/sec applications, where maintaining signal integrity under varying field conditions is challenging without sophisticated equipment like Eye Diagram inspection.
Innovation Solution
An optoelectronic transmitter with feedback circuitry that measures the power level of the modulated optical signal and adjusts the supply voltage to the digital driving circuitry, using a serializer-deserializer (SerDes) and optical power detector, to maintain a specified signal-to-noise ratio (SNR) by correlating RMS optical power with driving signal amplitude, thereby optimizing voltage usage and reducing power dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If over-estimation of voltage amplitude and power levels is used to maintain signal integrity, then signal quality is improved, but electrical power consumption increases excessively
Solution Approach 1:
The patent implements a feedback mechanism where the optical output power is monitored and used to adjust the SerDes supply voltage dynamically. The feedback circuitry measures the actual optical power level and adjusts the voltage amplitude accordingly, replacing fixed over-estimated voltage settings with adaptive control that maintains signal integrity while minimizing power consumption.
Solution Approach 2:
The patent transitions from static voltage amplitude settings to dynamic adjustment of the SerDes supply voltage. The voltage amplitude is made variable and adapts in real-time based on the measured optical power level, allowing the system to optimize power consumption while maintaining reliable signal transmission under varying conditions.
2Reliability
If high power levels are used to ensure signal quality under varying field conditions, then signal-to-noise ratio is improved, but cooling requirements and costs increase
Solution Approach 1:
The feedback circuitry continuously monitors the optical power level and adjusts the SerDes supply voltage to maintain the required signal-to-noise ratio. This dynamic adjustment prevents excessive power dissipation and heat generation by using only the necessary voltage amplitude to achieve the target SNR, thereby reducing cooling requirements.
Solution Approach 2:
The patent changes the supply voltage parameter dynamically based on the measured optical power level. By adjusting the voltage amplitude to match the actual signal requirements rather than using fixed high power levels, the system maintains adequate SNR while significantly reducing power dissipation and associated thermal management costs.
3Measurement precision
If sophisticated equipment like Eye Diagram inspection is used to maintain signal integrity, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts the essential measurement function from complex external equipment like Eye Diagram inspectors and implements a simplified feedback mechanism using basic optical power detection. The feedback circuitry measures the optical power level directly from the modulated signal, providing sufficient information for voltage adjustment without requiring sophisticated external measurement equipment.
Solution Approach 2:
The system performs self-diagnosis and self-adjustment by using the optical power measurement to automatically regulate its own supply voltage. The feedback circuitry enables the transmitter to monitor and control its signal quality without external sophisticated equipment, making the system self-sufficient and reducing overall device complexity.
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 minimizes electrical power consumption while ensuring optimal SNR, reducing the need for costly multi-chip solutions and cooling costs, and enabling more efficient integration and wider adoption of optical data center networks by accurately managing the SerDes power budget through real-time RMS-power wise control.
Implementation Method 1
an electro-optic modulator configured to modulate an optical signal in response to an electrical drive signal
Implementation Method 2
an optical power detector configured to receive a portion of the modulated optical signal from the optical modulator, and to measure the quantity by measuring a photocurrent proportional to the square root of the optical power level of the portion
Data Source
AI summary
An optoelectronic transmitter (10) includes an electro-optic modulator (12), digital driving circuitry (14), and feedback circuitry (30). The electro-optic modulator is configured to modulate an optical signal in response to an electrical drive signal. The digital driving circuitry is coupled to the electro-optical modulator and is configured to generate the electrical drive signal. The feedback circuitry is configured to measure a quantity indicative of a power level of the modulated optical signal produced by the electro-optic modulator, and to adapt a supply voltage to the digital driving circuitry in response to the measured quantity.