Optical Circulator Bidirectional Port LiDAR Cross-talk
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Solution Overview
Problem
LiDAR systems with separate or misaligned transmitting and receiving optical paths suffer from cross-talk and blind-spots, which overwhelm the return signal and hinder accurate spatial profile estimation of environments.
Innovation Solution
The use of an optical circulator with a bidirectional port for transmitting and receiving light, ensuring overlapping outgoing and incoming paths and high directivity, reduces cross-talk and blind-spots by aligning the optical paths, thereby enhancing the detection of spatial profiles in environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate transmitting and receiving optical paths are used in LiDAR systems, then the system can transmit and receive light independently, but cross-talk and blind-spots occur that overwhelm the return signal
Solution Approach 1:
The patent merges the transmitting and receiving optical paths by using a single bidirectional port for both functions. The optical circulator enables the same physical path to be used for both outgoing light transmission and incoming reflected light reception, eliminating the harmful cross-talk that occurs in separate path configurations while maintaining independent transmit/receive functionality through temporal separation and polarization management.
2Reliability
If separate transmitting and receiving optical paths are used, then independent operation is possible, but blind-spots are created that hinder accurate spatial profile estimation
Solution Approach 1:
By combining the transmit and receive paths into a single bidirectional path, the system eliminates blind-spots that occur at the boundaries between separate optical paths. The overlapping paths ensure continuous spatial coverage, allowing accurate estimation of spatial profiles without detection gaps.
3Reliability
If the output port is spatially displaced from the input port, then light directionality is improved, but the optical path alignment becomes more complex
Solution Approach 1:
The optical circulator acts as an intermediary device that manages the spatial displacement between input and output ports. It uses polarization-based beam splitting and combining mechanisms to redirect light paths, achieving high directivity while internally managing the alignment complexity through its structured optical core design.
Solution Approach 2:
The system changes the polarization state of light as it passes through the optical circulator. By manipulating polarization parameters (using birefringent crystals and waveplates), the system achieves spatial path separation and directionality control without requiring complex mechanical alignment, as the polarization state serves as an additional degree of freedom for path management.
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 achieves high directivity of at least 70 dB, allowing for simultaneous detection of multiple targets and reducing blind-spots, thereby improving the accuracy of spatial profile estimation and avoiding overwhelming the return signal.
Implementation Method 1
A first birefringent crystal, a non-reciprocal polarisation-rotating element following the first birefringent crystal
Implementation Method 2
a non-reciprocal polarisation-rotating element following the first birefringent crystal
Data Source
AI summary
Various forms of optical circulator are disclosed. The optical circulators act on polarisation of the light to direct light between its ports. Also disclosed are systems and methods for facilitating estimation of a spatial profile of an environment based on a light detection and ranging (LiDAR) based technique. The systems and method may include or use one or more of the various forms of optical circulator. In one arrangement, the present disclosure facilitates spatial profile estimation based on directing light over one dimension, such as along the vertical direction. In another arrangement, by further directing the one-dimensionally directed light in another dimension, such as along the horizontal direction, the present disclosure facilitates spatial profile estimation based on directing light in two dimensions.