Multi-Channel Tunable OLT Modules for Flexible Wavelength Configuration
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Solution Overview
Problem
WDM-PON systems face challenges in maintaining flexible wavelength configuration with high cost and large tuning range requirements for tunable optical modules, limiting their ability to support transmission rates above 10 Gbps and increasing bandwidth demands.
Innovation Solution
The implementation of an optical line terminal (OLT) with N tunable modules, each containing M tunable transmitters with a reduced number of tuning channels, allowing for flexible wavelength configuration while minimizing the tuning range and cost, using multi-channel tunable modules with shared wavelength tuning channels and optical switching for port protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple bidirectional single-fiber tunable optical modules are used to implement wavelength flexible configuration, then wavelength adaptability is improved, but the tuning range requirement becomes very large and cost increases significantly
Solution Approach 1:
The patent divides the wavelength tuning function into multiple independent tunable transmitters, each responsible for a subset of wavelength channels. Instead of requiring a single optical module to tune across all M×N wavelengths, each transmitter is assigned to tune over a smaller range (at least two channels but less than M×N), thereby segmenting the overall tuning requirement and reducing individual module complexity.
Solution Approach 2:
The patent combines multiple tunable transmitters within a single optical module to achieve the overall wavelength flexible configuration capability. By merging several transmitters with reduced tuning ranges into one module, the system attains the adaptability of covering all M×N wavelength pairs without requiring each component to have a excessively large tuning range, thus resolving the contradiction between adaptability and device complexity.
2Adaptability or versatility
If multiple bidirectional single-fiber tunable optical modules are used to implement wavelength flexible configuration, then wavelength adaptability is improved, but cost increases very high
Solution Approach 1:
The patent segments the wavelength tuning function across multiple transmitters with smaller individual tuning ranges. This segmentation allows each transmitter to be manufactured with lower cost components compared to a single high-performance transmitter covering the entire M×N wavelength range, thereby reducing overall system cost while maintaining wavelength flexible configuration capability.
Solution Approach 2:
The patent designs optical modules with multi-functional tunable transmitters that can serve multiple wavelength channels. Each transmitter is designed to be universal in handling different wavelength assignments, allowing the same module design to be reused across multiple PON ports and wavelength configurations, which reduces manufacturing cost through standardization while preserving adaptability.
3Adaptability or versatility
If external-seeded injection locking or self-seeded injection locking is used, then wavelength adaptability is improved, but transmission rate support is limited above 10 G
Solution Approach 1:
The patent uses multiple independent tunable transmitters that can be configured to copy or replicate wavelength assignment patterns across different PON ports. Each transmitter independently generates optical signals at its assigned wavelength, avoiding the need for complex injection locking mechanisms while achieving wavelength adaptability. This direct generation approach supports higher transmission rates above 10 G by eliminating the bandwidth limitations of injection-locked laser schemes.
Data Source
AI summary
Disclosed is an optical line terminal (OLT), including: N tunable modules, each of the N tunable modules include M tunable transmitters, the number of tuning channels of the M tunable transmitters is greater than or equal to two and the number of the tuning channels is less than M×N, wherein N and M are integers greater than or equal to two.