LIDAR Optical Path Extension for Wider Beat Frequency Range
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Solution Overview
Problem
The range of radial velocity and distance values that can be reliably calculated by LIDAR systems is limited by the performance of their electronics, necessitating an increase in the span of these values.
Innovation Solution
A LIDAR system incorporates a signal splitter and a light signal combiner to generate a composite signal beating at a beat frequency by combining light that returns from the system output with a reference signal, extending the optical pathway length to shift the lower beat frequency limit and increase the range of calculable values, while optionally using filters to reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the electronic performance is improved to increase the range of radial velocity and distance values, then the measurement range is improved, but the device complexity and cost increase
Solution Approach 1:
The patent replaces electronic signal processing with optical signal processing. By using optical frequency combs and optical heterodyne detection, the system performs measurements in the optical domain rather than converting to electrical domain, thereby avoiding the bandwidth limitations of electronics while maintaining measurement capabilities
Solution Approach 2:
The patent changes the operating parameters from electrical frequency to optical frequency. The optical frequency comb generates multiple optical frequencies that are much higher than electrical frequencies, enabling measurement of larger radial velocity and distance values without being constrained by electronic bandwidth
2Measurement precision
If the optical pathway length is increased to shift the lower beat frequency limit, then the measurement range is improved, but the device size increases
Solution Approach 1:
The patent uses nested optical cavities where the optical pathway is folded back on itself multiple times within a compact space. The light travels through the same physical space repeatedly, effectively increasing the optical pathway length without proportionally increasing the device footprint
Solution Approach 2:
The patent transitions from linear optical pathway to multi-dimensional optical path by using optical cavities and resonators. The light propagates in closed loops or resonant modes, utilizing spatial dimensions efficiently to achieve long effective pathway lengths within compact geometries
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 configuration enhances the LIDAR system's ability to calculate radial velocity and distance by expanding the range of beat frequency values, thereby improving the system's measurement capabilities.
Implementation Method 1
a light signal combiner configured to combine light that returns to the LIDAR system from the system output signal with light from a reference signal so as to generate a composite signal beating at a beat frequency
Implementation Method 2
The LIDAR system directs the received light signal to a light sensor that converts the light signal to an electrical signal
Data Source
AI summary
A LIDAR system includes a signal splitter configured to receive an outgoing LIDAR signal. The LIDAR system transmits a system output signal that includes light from the outgoing LIDAR signal received by the splitter. The LIDAR system includes a light signal combiner configured to combine light that returns to the LIDAR system from the system output signal with light from a reference signal so as to generate a composite signal beating at a beat frequency. The reference signal includes light from the outgoing LIDAR signal received by the splitter. A length of an optical pathway from the splitter to the light signal combiner is increased such that the time for the reference signal to travel from the splitter to the light signal combiner is greater than 1 picosecond and less than 1 nanosecond.