OADM Loopback Validation for Optical Connection Reliability
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Solution Overview
Problem
Fibre optic communication systems face issues with misconnections due to the absence of filtering in Optical Add/Drop Multiplexers (OADM), leading to traffic outages when transmitters of the same wavelength are connected to the same multiplexer, which is problematic in systems using tunable lasers and coherent transmitters/receivers.
Innovation Solution
A loopback mechanism is introduced to test and validate the physical connection between transmitters/receivers and the OADM, preventing the tuning of new transmitters to already in-use channels by using an out-of-band channel for testing and confirming connections, and optionally employing power monitoring taps to determine connected add/drop ports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If manual fibre cable installation is used to connect transmitters to OADM, then system flexibility and upgradeability are improved, but connection reliability deteriorates due to human error causing misconnections
Solution Approach 1:
The system performs preliminary connection validation by transmitting test signals through the fibre connection before allowing normal operation. The validation process checks whether the physical connection matches the logical configuration, preventing misconnections from causing outages. This preliminary check ensures that manual installation flexibility does not compromise system reliability.
2Device complexity
If tunable lasers are used to reduce product variants, then inventory complexity is reduced, but the risk of wavelength conflicts increases when misconnections occur
Solution Approach 1:
The system implements feedback mechanisms where the OADM monitors transmitted wavelengths and reports back to the transmitter. When a transmitter is tuned to a wavelength, the system verifies through feedback that no other transmitter on the same OADM is using that wavelength. This feedback loop prevents wavelength conflicts that could result from misconnections, enabling the use of tunable lasers without increasing conflict risk.
3Ease of manufacture
If optical filters are removed from OADM to reduce cost, then device cost is reduced, but the ability to prevent misconnections deteriorates
Solution Approach 1:
The patent replaces optical filtering mechanisms with electronic/validation-based connection verification. Instead of using optical filters to physically prevent misconnections, the system uses validation processes that detect and prevent misconnections through signal transmission and verification. This substitution maintains misconnection prevention capability while reducing device cost by eliminating expensive optical filter components.
Data Source
AI summary
An optical add/drop multiplexer (OADM) having an Add path for adding optical channel signals input through a plurality of Add ports to an outbound dense wavelength division multiplexed (DWDM) signal, and a Drop path for switching selected channels from an inbound DWDM signal to one or more of a plurality of Drop ports. The OADM has a loopback connection between the Add path and the Drop path. The loopback connection couples a selected loopback channel wavelength from the Add path to the Drop path. The physical connection between a transceiver and the OADM can be verified by connecting the transmitter to an Add port of the OADM and the receiver to a Drop port of the OADM. The OADM is controlled to switch the selected loopback channel wavelength in the Drop path to at least one intended drop port to which the receiver should be connected, and the transmitter is controlled to transmit a predetermined test signal using the loopback channel wavelength. Detecting the test signal by the receiver verifies that the receiver is connected to the at least one intended drop port.