Laser Array Mux Assembly with External Reflector for Wavelength Selection
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Solution Overview
Problem
Current WDM-PON systems face inefficiencies in bandwidth utilization and transmitter versatility due to reliance on time-domain multiplexing and the high cost and complexity of continuously tunable lasers, which are sensitive to environmental conditions.
Innovation Solution
A laser array mux assembly with an external reflector is used, comprising an array of laser emitters coupled to an optical multiplexer like an arrayed waveguide grating, which filters and reflects light to achieve wavelength-selectable or multiplexed optical signals, allowing for universal, colorless transmitters capable of tuning to different wavelengths without external locking mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If continuously tunable lasers are used to provide wavelength selection in WDM-PON systems, then wavelength versatility is improved, but device complexity and cost increase due to tight manufacturing tolerances and environmental sensitivity
Solution Approach 1:
The invention segments the wavelength selection function into discrete wavelength slots using an arrayed waveguide grating (AWG) that routes different wavelengths to different output ports. Instead of continuously tuning a single laser, the system uses multiple fixed-wavelength laser emitters (e.g., 16 discrete wavelengths) where each emitter corresponds to a specific wavelength slot. This segmentation provides wavelength versatility while avoiding the complexity of continuous tuning mechanisms.
Solution Approach 2:
The invention replaces expensive, complex continuously tunable lasers with simpler, less expensive fixed-wavelength laser emitters. Each laser emitter is designed to operate at a specific wavelength without requiring complex tuning mechanisms or tight manufacturing tolerances. This substitution reduces device complexity and cost while maintaining wavelength versatility through the array of discrete emitters.
2Adaptability or versatility
If continuously tunable lasers are used for wavelength selection, then wavelength adaptability is improved, but manufacturing precision requirements become excessively tight and costly
Solution Approach 1:
The wavelength adaptation function is segmented into discrete wavelength slots handled by individual fixed-wavelength laser emitters. Each emitter is manufactured to operate at a specific wavelength without requiring ultra-tight tolerances for continuous tuning. The AWG device segments the optical signals and routes them to appropriate output ports, providing wavelength adaptability through configuration rather than precision manufacturing.
Solution Approach 2:
The invention changes the operating parameter from continuous wavelength tuning to discrete wavelength selection. Instead of requiring lasers to be manufactured with tight tolerances for continuous operation across a wavelength range, the system uses fixed-wavelength emitters where the wavelength parameter is determined by the AWG routing configuration rather than manufacturing precision.
3Device complexity
If time-domain multiplexing is used in PON systems, then fiber deployment complexity is reduced, but bandwidth utilization efficiency deteriorates
Solution Approach 1:
The invention transitions from time-domain multiplexing (periodic time slots) to wavelength-domain multiplexing (simultaneous periodic wavelength channels). Multiple wavelengths can transmit data simultaneously and continuously through the same fiber, eliminating the need for time slot allocation and stabilization periods. This provides periodic wavelength channels that maintain simple fiber deployment while dramatically improving bandwidth utilization.
Solution Approach 2:
The invention moves the multiplexing dimension from time to wavelength. Instead of sharing the fiber in time domains with sequential access, multiple wavelengths occupy different frequency dimensions simultaneously. This dimensional transition allows parallel data transmission across the same physical fiber, improving productivity while maintaining deployment simplicity.
4Object-affected harmful factors
If TDM-PON burst mode transmission is used to reduce noise, then noise levels are controlled, but data rate increases become challenging
Solution Approach 1:
The invention uses periodic wavelength-based transmission channels that can operate continuously without burst mode switching. Each wavelength channel provides a stable, dedicated transmission path that maintains low noise levels through continuous operation rather than rapid on/off switching. This periodic wavelength allocation enables higher data rates by eliminating the stabilization time requirements of burst mode TDM.
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 enhances bandwidth utilization and transmitter versatility, reducing costs and environmental sensitivity by enabling efficient wavelength selection and multiplexing, thus improving data transmission rates and ease of deployment in WDM-PON systems.
Implementation Method 1
an optical multiplexer (e.g., an arrayed waveguide grating) that filters light from the laser emitters at different channel wavelengths
Implementation Method 2
an external partial reflector that reflects a portion of the filtered light back to a gain region in the respective laser emitters such that a lasing cavity is formed
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A laser array mux assembly generally includes an array of laser emitters coupled to an optical multiplexer, such as an arrayed waveguide grating (AWG), with an external partial reflector after the multiplexer. Each of the laser emitters may include a gain region that emits light across a range of wavelengths including, for example, channel wavelengths in an optical communication system. The AWG filters the emitted light from each of the laser emitters at different channel wavelengths associated with each of the laser emitters. The reflector reflects at least a portion of the filtered light such that lasing occurs at the channel wavelengths of the reflected light. The laser array mux assembly may be used to generate an optical signal at a selected channel wavelength or to generate and combine optical signals at multiple channel wavelengths.