Electro-Optical Phase-Locked Loop for Low-Noise 100+ GHz Clocking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electronic devices face challenges in supporting high data rates for wireless communications due to limitations in providing low jitter and low phase noise clocking for wireless circuitry at frequencies above 100 GHz, making it difficult to meet the increasing demand for data-intensive applications.
Innovation Solution
The implementation of an electro-optical phase-locked loop (OPLL) using a primary and secondary laser to generate optical local oscillator signals, with a frequency-locked loop (FLL) and phase-locked loop (PLL) paths to finely tune the secondary laser, ensuring minimal jitter and phase noise, enabling wireless signals to be conveyed at frequencies greater than 100 GHz.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wireless communications operate at higher frequencies to support higher data rates, then data rate capability is improved, but clocking quality (jitter and phase noise) deteriorates
Solution Approach 1:
The patent introduces an optical domain as an intermediary to solve the RF clocking problem. Instead of directly generating and distributing RF clock signals at frequencies above 100 GHz, the system converts RF signals to optical signals, processes them in the optical domain where stable oscillation is easier to achieve, and then converts back to RF. This intermediary optical domain acts as a buffer that preserves signal integrity while enabling high-frequency operation.
Solution Approach 2:
The patent replaces traditional electrical/electronic clocking mechanisms with optical mechanisms. Instead of using electronic oscillators and phase-locked loops that struggle at frequencies above 100 GHz, the system uses optical oscillators and optical phase-locked loops that can maintain stability at these frequencies. The optical domain provides a different physical mechanism for frequency generation and stabilization that overcomes the limitations of electrical systems.
2Speed
If traditional electrical clocking is used at frequencies above 100 GHz, then wireless communication frequency is improved, but jitter and phase noise increase
Solution Approach 1:
The optical domain serves as an intermediary that enables high-frequency operation with low phase noise. The system modulates RF signals onto optical carriers, allowing the benefits of optical stability to be transferred to the RF domain. This intermediary approach allows the system to operate at frequencies above 100 GHz while maintaining low jitter and phase noise through the stability of optical oscillators.
Solution Approach 2:
The patent changes the fundamental parameter domain from electrical to optical. By operating in the optical domain for clocking and signal processing, the system accesses different physical characteristics including higher Q-factors and better phase noise performance. This parameter change from electrical frequency to optical frequency enables stable operation at RF frequencies above 100 GHz that would be difficult to achieve with purely electrical systems.
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 solution allows for efficient transmission and reception of wireless signals at high frequencies with minimal jitter and phase noise, supporting higher data rates and addressing the limitations of existing technologies in wireless circuitry.
Implementation Method 1
A photodiode may be interposed on both the FLL path and the PLL path. The photodiode may generate a photodiode signal based on the first and second optical LO signals.
Data Source
AI summary
An electronic device may include wireless circuitry clocked using an electro-optical phase-locked loop (OPLL) having primary and secondary lasers. A frequency-locked loop (FLL) path and a phase-locked loop (PLL) path may couple an output of the secondary laser to its input. A photodiode may generate a photodiode signal based on the laser output. A digital-to-time converter (DTC) may generate a reference signal. The FLL path may coarsely tune the secondary laser based on the photodiode signal until the secondary laser is frequency locked. Then, the PLL path may finely tune the secondary laser based on the reference signal and the photodiode signal until the phase of the secondary laser is locked to the primary laser. The photodiode signal may be subsampled on the PLL path. This may allow the OPLL to generate optical local oscillator signals with minimal jitter and phase noise.