Tunable Laser Mode Change Buffering for WDM PON
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Solution Overview
Problem
WDM PON systems face high initial implementation costs due to expensive optical components, and tunable lasers in these systems often require temperature control, leading to increased costs and potential data transmission interruptions during mode changes.
Innovation Solution
A method for handling mode changes in tunable laser transmitters by monitoring their state and selecting a suitable time for the change, buffering data during the transition, and resuming transmission only when the laser reaches a stable state, thereby avoiding data loss and eliminating the need for temperature control mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If temperature control mechanisms are implemented in tunable lasers, then mode stability is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts and removes the temperature control mechanism from the tunable laser system. By operating without active temperature control, the system eliminates the associated complexity and cost while managing mode changes through alternative means (monitoring and buffering mechanisms) that address stability issues without thermal management hardware
Solution Approach 2:
The system allows the tunable laser to self-regulate its temperature and mode changes without external control. The natural thermal behavior of the laser is monitored and accommodated through the patent's notification and buffering mechanisms, rather than actively controlling the temperature to prevent mode changes
2Speed
If mode change is initiated immediately, then response time is improved, but data loss increases
Solution Approach 1:
The patent sends a notification about the upcoming mode change before the actual mode change occurs. This preliminary action allows the receiving system to prepare by buffering incoming data, ensuring that no data is lost during the transition. The notification triggers preparatory buffering actions in advance of the mode change event
Solution Approach 2:
The patent implements a buffering mechanism that cushions against data loss during mode changes. By buffering data before the mode change completes and confirming receipt after, the system creates a protective buffer zone that prevents data loss even though the mode change proceeds at its natural speed without delay
3Loss of information
If buffering is implemented during mode change, then data loss is reduced, but transmission time increases
Solution Approach 1:
The patent uses periodic action in the form of confirmation messages exchanged between transmitting and receiving ends. The receiving end sends periodic confirmations about data receipt status, and the transmitting end uses these confirmations to determine when to resume transmission. This periodic exchange efficiently coordinates the buffering and resumption processes without requiring continuous interruption
Solution Approach 2:
The patent implements feedback mechanisms where the receiving end notifies the transmitting end about data receipt status. This feedback allows the system to make informed decisions about when to buffer and when to resume transmission, optimizing the balance between preventing data loss and minimizing transmission interruption time
Data Source
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AI summary
A method at a transmitter of a tunable laser of controlling a mode change of the laser during a transmission of data to a receiver of a terminating node is based on the determination of a time instance for initiation of the mode change on the basis of the state of the tunable laser. In addition, buffer occupancy and/ or the state of the data transmission may be considered when determining such a time instance. In addition, data of the data transmission is buffered during the mode change, such that data loss is avoided during the change of mode. A transmitter is also provided which can execute the suggested mode changing method.