Optical Phase Detector Using Photoelectric Reference Signal
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Solution Overview
Problem
Traditional time-of-flight (TOF) based sensors require an additional phase detector for synchronization with an external microwave signal source, leading to a complex structure and increased costs, while also facing limitations in phase noise performance and timing resolution.
Innovation Solution
An optical phase detection system that uses photo-electrically converted electrical pulses as a reference signal, eliminating the need for an external synchronization phase detector and utilizing inexpensive photodiodes to achieve high resolution measurements by detecting phase errors through rising edges or sinusoidal waveforms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an external microwave signal source (VCO) is used for TOF detection, then the measurement can be performed, but an additional phase detector for synchronization is required, increasing device complexity
Solution Approach 1:
The system uses the optical pulses themselves to generate the reference signal through photoelectric conversion, eliminating the need for external VCO and separate synchronization phase detector. The optical pulse train is converted to electrical pulses that serve as the reference signal for phase comparison, making the system self-sufficient.
Solution Approach 2:
The patent replaces the traditional electronic microwave signal generation system (VCO) with an optical-based reference signal generation system. By using photoelectric conversion of optical pulses, the system substitutes the mechanical/electronic oscillation system with an optical timing reference system.
2Measurement precision
If an external VCO is used as signal source, then TOF measurement is enabled, but another phase detector is needed for synchronizing the microwave signal, increasing cost
Solution Approach 1:
The system generates its own reference signal from the optical pulse train through photoelectric conversion, eliminating the need to purchase and integrate expensive external VCO and synchronization phase detector components. This self-service approach reduces overall system cost.
Solution Approach 2:
The optical pulse train serves multiple functions: it is both the measurement signal and the source of the reference signal. By using the same optical pulses for both measurement and reference generation, the system eliminates the need for separate signal generation components, reducing cost.
3Measurement precision
If traditional TOF-based sensor structure is used, then distance measurement can be performed, but the structure becomes complex and costs increase
Solution Approach 1:
The patent merges the reference signal generation function with the optical pulse train. By photoelectrically converting the optical pulses to generate the reference signal, the system combines what were previously separate functions (optical measurement signal and electronic reference signal) into a unified optical-based system.
Solution Approach 2:
The patent extracts the reference signal directly from the optical pulse train through photoelectric conversion, removing the need for external microwave signal generation components. This extraction approach simplifies the overall system structure by eliminating unnecessary components.
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 system simplifies the structure, reduces costs, and enhances phase noise performance and timing resolution, enabling high-resolution TOF measurements with a single optical phase detector and photoelectric conversion device.
Implementation Method 1
an electrical pulse generator that receives first optical pulses output from a pulsed laser, through a first path, and photo-electrically converts the first optical pulses to generate electrical pulses
Implementation Method 2
an optical phase detector that receives second optical pulses output from the pulsed laser, through a second path, and outputs an electrical signal that corresponds to a phase error between the electrical pulses and the second optical pulses based on electro-optic sampling
Data Source
AI summary
A sensing system is provided. The sensing system includes an electrical pulse generator that receives first optical pulses output from a pulsed laser, through a first path, and photo-electrically converts the first optical pulses to generate an electrical pulses; and an optical phase detector that receives second optical pulses output from the pulsed laser, through a second path, and outputs an electrical signal that corresponds to a phase error between the electrical pulses and the second optical pulses based on electro-optic sampling.