Optical Phased Array Waveguide Phase Error Reduction
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Solution Overview
Problem
Large-scale optical phased arrays face significant phase errors due to uncertainty in waveguide width caused by process errors, leading to degradation of far-field spot quality and increased propagation loss from extensive connecting waveguides.
Innovation Solution
The optical phased array design incorporates a waveguide unit with M waveguide pipes, each containing an input mode converter to convert a narrow waveguide into a wide waveguide, and an output mode converter to convert the wide waveguide back into a narrow waveguide, reducing phase errors by minimizing width changes and using wide waveguides for straight transmission and narrow waveguides for curved sections to filter higher-order modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If narrow waveguides are used throughout the optical phased array, then phase precision is improved, but propagation loss increases and device complexity increases due to numerous curved connections
Solution Approach 1:
The waveguide system is segmented into different sections with different waveguide widths. Narrow waveguides are used in critical phase-control regions while wide waveguides are used in non-critical transmission regions, allowing each segment to be optimized for its specific function.
Solution Approach 2:
Different regions of the waveguide system are assigned different local qualities (narrow vs wide waveguide widths) according to their functional requirements. Phase-critical regions use narrow waveguides for precision, while transmission regions use wide waveguides for low loss.
2Area of stationary object
If narrow waveguides are used for curved connections, then device area is reduced, but manufacturing precision deteriorates due to process errors
Solution Approach 1:
The waveguide path is divided into curved sections (using narrow waveguides for compactness) and straight sections (using wide waveguides for precision). This segmentation allows curved connections to achieve area reduction while straight sections maintain manufacturing precision.
Solution Approach 2:
Mode converters serve as intermediary elements that bridge narrow and wide waveguide sections. They enable transitions between different waveguide widths while maintaining mode purity and minimizing phase errors.
3Ease of operation
If many connecting waveguides are used to connect phase shifters to antenna units, then device functionality is achieved, but device complexity increases and propagation loss increases
Solution Approach 1:
Multiple narrow waveguide paths are merged into a single wide waveguide for non-critical transmission sections. This reduces the total number of waveguide components while maintaining the necessary functionality through subsequent mode conversion.
Solution Approach 2:
The essential phase-control function is extracted and concentrated in specific narrow waveguide sections, while non-essential transmission sections use simpler wide waveguides. This separates critical from non-critical functions in the waveguide network.
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 design significantly reduces phase errors and propagation loss by minimizing width changes in waveguides, improving the far-field spot quality and reducing the need for unnecessary connecting waveguides, thus enhancing the performance of large-scale optical phased arrays.
Implementation Method 1
each waveguide pipe includes at least one connection waveguide, the at least one connection waveguide includes an input mode converter, a wide waveguide, and an output mode converter that are connected in sequence. The input mode converter is configured to convert a narrow waveguide into a wide waveguide, the output mode converter is configured to convert a wide waveguide into a narrow waveguide
Data Source
AI summary
An optical phased array, a method for reducing a phase error thereof, a LiDAR, and an intelligent apparatus are provided. The optical phased array includes an optical signal output unit, a waveguide unit, and an antenna transmitting unit. The optical signal output unit is configured to output M optical signals. The waveguide unit includes M waveguide pipes, each waveguide pipe includes at least one connection waveguide, and each of the at least one connection waveguide includes an input mode converter, a wide waveguide, and an output mode converter that are connected in sequence. The antenna transmitting unit is configured to transmit M optical signals outputted from the waveguide unit.