Repeater Using Identical Lasers and Common Waveguide
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing repeaters for mobile networks in areas with radio wave shadows, such as tunnels, require separate optical waveguides for each remote unit due to the need for distinct laser wavelengths, leading to increased costs and complexity in maintenance.
Innovation Solution
A repeater system using identical lasers with adjustable operating temperatures for remote units, allowing them to transmit on different wavelengths, and a common optical waveguide for signal transmission, reducing the need for multiple laser types and waveguides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate optical waveguides are used for each remote unit, then signal separation is achieved, but device complexity and cost increase
Solution Approach 1:
Multiple separate optical waveguides are merged into a single common optical waveguide that carries all remote unit signals. The waveguide is structured with multiple signal paths that remain optically separated through the use of different wavelengths, achieving both consolidation and signal separation.
Solution Approach 2:
The solution moves from spatial separation (separate waveguides) to spectral separation (different wavelengths within a single waveguide). By adding the wavelength dimension as a distinguishing feature, multiple signals can coexist in one physical medium without interference.
2Reliability
If different laser types are used for each remote unit, then spectral separation is achieved, but ease of manufacture and maintenance worsen
Solution Approach 1:
All remote units use identical laser types with the same nominal wavelength characteristics. This homogenization simplifies manufacturing, inventory management, and maintenance. The spectral separation previously achieved through different laser types is now achieved through wavelength tuning of identical lasers.
Solution Approach 2:
Instead of changing the laser type (fundamental design parameter), the solution changes the operating wavelength parameter of identical lasers. Each laser is tuned to a specific wavelength within the same spectral band, allowing spectral separation while maintaining component uniformity.
3Device complexity
If a common optical waveguide is used for multiple remote units, then device complexity is reduced, but signal separation becomes more difficult
Solution Approach 1:
The solution introduces wavelength as an additional dimension for signal differentiation. Within the single optical waveguide, signals from different remote units are transmitted at different wavelengths, enabling clear separation despite physical coexistence in the same medium.
Solution Approach 2:
Wavelength-specific optical filters or demultiplexers act as intermediaries that separate the combined signal from the common waveguide into individual wavelength channels. These intermediaries enable reliable signal separation while maintaining the simplicity of the common waveguide structure.
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 approach simplifies maintenance and reduces costs by using identical lasers for remote units, achieving effective signal separation and transmission with a single common optical waveguide, while maintaining a high degree of prefabrication and spectral separation.
Implementation Method 1
These lasers are selected, by adjusting their operating temperatures, in such a way that each laser transmits on a different transmission wavelength
Implementation Method 2
Signal transmission between the master unit and the remote units is often effected as an amplitude-modulated optical analog signal via one or several optical waveguides, for example optical fiber or glass cables
Data Source
AI summary
A repeater (1) includes a master unit (2) for communicating with a base station of a mobile network, a plurality of remote units (3) for communicating with mobile communications terminals, and a common optical waveguide (4) connecting the remote units (3) with the master unit (2) for transmitting the optical signals from each of the remote units (3) to the master unit (2). The remote units (3) include, as a transmitter for the optical signals, a laser (7) of a construction similar or somewhat identical to that of the other lasers (7). The lasers (7) have similar or somewhat identical nominal wavelengths (λN), and the individual lasers (7) are selected by adjusting their operating temperatures (TD1-TD4) in such a way that each laser transmits on a different transmission wavelength (λü1-λü4).