Broadband Optical Coupler for Multi-Wavelength Beam Steering
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Solution Overview
Problem
Conventional non-mechanical beam-steering devices have narrow-band phase-matching conditions and are sensitive to the external angle of the source, limiting their wavelength and angular acceptance, making them unsuitable for wide-bandwidth and multi-line sources.
Innovation Solution
The development of a broadband optical coupler with multiple thin-film layers having spatially varying optical thicknesses, which expands the wavelength and angular acceptance by maintaining a constant effective index across a broad band of wavelengths, allowing simultaneous coupling of multiple wavelengths at a single external angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional non-mechanical beam-steering devices use narrow-band phase-matching conditions, then coupling efficiency at specific wavelengths is improved, but wavelength acceptance bandwidth deteriorates
Solution Approach 1:
The coupler is segmented into multiple thin-film layers (first thin-film layer, second thin-film layer, third thin-film layer) with different optical thicknesses. Each layer segment contributes to phase-matching at different wavelengths, enabling broadband coupling by dividing the wavelength spectrum into multiple segments that are handled by respective layer segments.
Solution Approach 2:
Different regions of the coupler structure have different optical properties - the first thin-film layer has a first optical thickness optimized for first wavelengths, the second thin-film layer has a second optical thickness optimized for second wavelengths, and the third thin-film layer has a third optical thickness optimized for third wavelengths. This local optimization of optical thickness at different spatial positions enables simultaneous phase-matching across broad wavelength bands.
2Measurement precision
If conventional beam-steering devices use fixed coupling geometry, then alignment precision is improved, but angular acceptance deteriorates
Solution Approach 1:
The coupler structure incorporates dynamic adaptability through multiple thin-film layers with different optical thicknesses that can handle different incident angles. This dynamic structure allows the coupler to maintain phase-matching conditions across a range of angles by utilizing the different optical path lengths through each layer, effectively expanding angular acceptance while maintaining coupling efficiency.
3Reliability
If conventional devices use single-wavelength optimization, then performance at specific wavelength is improved, but multi-line source compatibility deteriorates
Solution Approach 1:
The coupler is designed with multi-functionality to handle multiple wavelength lines simultaneously. The first thin-film layer, second thin-film layer, and third thin-film layer each contribute to coupling different wavelength ranges, making the single coupler structure universal for multi-line sources. This eliminates the need for separate couplers for different wavelengths while maintaining reliable coupling performance across all lines.
4Ease of manufacture
If conventional beam-steering devices use traditional coupling structures, then manufacturing simplicity is improved, but bandwidth limitation worsens
Solution Approach 1:
The coupler employs a composite structure made of multiple thin-film layers with different optical properties and thicknesses. This composite design combines the advantages of different material layers to achieve broadband coupling performance that would be impossible with a single homogeneous structure, while still using standard thin-film deposition manufacturing techniques.
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 significantly increases the bandwidth and angular acceptance, making the couplers source-agnostic and robust to manufacturing and vibration errors, enabling simultaneous coupling of multiple sources in a single refractive beam-steering device.
Implementation Method 1
multiple thin-film layers having spatially varying optical thicknesses, which expands the wavelength and angular acceptance by maintaining a constant effective index across a broad band of wavelengths
Implementation Method 2
broadband optical coupler with multiple thin-film layers having spatially varying optical thicknesses, which expands the wavelength and angular acceptance
Data Source
AI summary
An optical system has a beam-steering device, a light source, and a controller that controls the light source to actively control wavelength of the incoming light to control the output angle of the outgoing light output from the BS device. The BS device may have incoupler, waveguide, and/or outcoupler electrodes, and the system may have corresponding controllable voltage supplies actively controlled by the controller to selectively modify electric fields applied to the BS device to control corresponding operating characteristics of the BS device (e.g., in-plane and/or out-of-plane output angles of the outgoing light and/or device incoupling angle). An alternative optical system has a BS device, a detector array that generates detector signals corresponding to outgoing light received from the BS device, and a controller that processes the detector signals to determine one or more wavelengths of the outgoing light.