Tunable Laser Light Source for Li-Fi Beam Scanning
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Solution Overview
Problem
Existing Li-Fi communication systems face interference issues due to multiple devices sharing bandwidth, leading to reduced data rates, and point-to-point communication setups with two gratings are complex and require extensive scanning.
Innovation Solution
A tunable laser-based light source with a scanning beam that is broadened by a second optical element, allowing for one-dimensional scanning, reducing complexity and increasing scanning speed, and utilizing a wavelength-tunable laser with a diffraction grating or rotatable mirror to eliminate the need for moving parts and enhance scanning resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If two gratings are used for beam steering in point-to-point communication, then the system achieves narrow beam steering capability, but the device complexity and scanning time increase significantly
Solution Approach 1:
The patent extracts the beam broadening function from the complex two-grating system and implements it through a single grating combined with optical elements (lens or reflector). This reduces the system from multiple moving parts to a single stationary grating, thereby reducing device complexity while maintaining scanning capability.
Solution Approach 2:
The patent replaces the mechanical two-grating steering system with an optical system using a single grating and broadening elements. The beam broadening is achieved through optical means rather than mechanical adjustment of multiple gratings, reducing moving parts and simplifying the mechanical system.
2Measurement precision
If a narrow scanning beam is used for point-to-point communication, then the beam can be precisely directed, but the scanning time and complexity increase
Solution Approach 1:
The patent performs preliminary beam broadening before the scanning operation. By pre-broadening the beam using optical elements before it enters the scanning grating, the system reduces the scanning time required while maintaining precise directional control through the grating's diffraction properties.
Solution Approach 2:
The patent introduces a spatial dimension by broadening the beam in one dimension (perpendicular to the scanning direction) while maintaining narrow confinement in the scanning dimension. This dimensional separation allows continuous coverage in the broadening direction without increasing scanning time in the primary scanning direction.
3Area of stationary object
If multiple devices share the same Li-Fi access point bandwidth, then coverage area increases, but interference increases and data rates decrease
Solution Approach 1:
The patent segments the coverage area into multiple narrow directional beams that can be independently controlled. Each beam serves a specific directional sector, reducing interference between devices by spatially separating their communication channels while collectively providing broad coverage through coordinated beam steering.
Solution Approach 2:
The patent extends coverage by adding spatial dimension through beam steering capability. Instead of increasing power or bandwidth in a single direction, the system creates multiple directional beams that can be steered to cover different areas, achieving broad coverage without increasing interference in any single direction.
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 solution reduces scanning time and complexity, enables higher scanning speeds, minimizes mechanical malfunctions, and improves signal-to-noise ratio by allowing continuous scanning with reduced degrees of freedom, making it suitable for high-speed Li-Fi systems.
Implementation Method 1
the first optical element is a diffraction grating, thereby allowing the scanning beam reflected/refracted to be swept along the scanning direction when the wavelength is changed
Implementation Method 2
a laser for in operation emitting a scanning beam
Data Source
AI summary
A tunable laser based light source for Li-Fi communication comprising a laser (1), a first optical element (3), and a second optical element (4). The first optical element (3) is configured to reflect and/or refract a scanning beam (2) emitted from the laser (1). The second optical element (4) is configured to broaden the scanning beam (2) reflected/refracted by the first optical element (3). The scanning beam (2) is configured to scan a scanning area extending with a first scanning length in a broadening direction (SI) and a second scanning length in a scanning direction (S2). The second optical element (4) is configured to broaden the scanning beam (2) in the broadening direction (S1) to a width larger than the first scanning length, and the laser (1) and the first optical element (3) are configured to cooperate to enable the scanning beam (2) to be swept along the scanning direction (S2).