Brief description
This report checks the correctness of the line engineering design of the point-to-point WDM links in an optical network, following the guidelines described in ITU-T Manual 2009 "Optical fibres, cables and systems" (chapter 7, section 2 Worst case design for system with optical line amplifiers).
Algorithm description table
| Algorithm inputs | The report has multiple input parameters, described in the report text |
|---|---|
| Algorithm outputs | HTML report |
| Required libraries | None |
| Keywords | WDM |
| Authors | Pablo Pavón Mariño, José Luis Izquierdo Zaragoza |
| Date | February 2014 |
| Code | Report_WDM_pointToPointLineEngineering.java |
Detailed description
The report assumes that the network links are WDM optical fibres with the following scheme:
- A transmitter per WDM channel with the specifications given by "tp__XXX". The number of channels can vary from one to up to channels_maxNumChannels and, the design should be correct in all the cases. Transmitter specifications are set in "tp__XXX" input parameters
- A multiplexer that receives the input power from the transmitters and with specifications given by "mux__XXX" parameters
- A fiber link of a distance given by the link length, and with specifications given by "fiber__XXX" parameters. The fiber can be split into spans if optical amplifers (EDFAs) and/or dispersion compensating modules (DCMs) are placed along the fibre.
- A set of optical amplifiers (EDFAs) located in none, one or more positions in the fiber link, separating them in different spans. EDFAs are supposed to operate in the automatic gain control mode. Thus, the gain is the same, whatever the number of input WDM channels. EDFA positions (as distance in km from the link start to the EDFA location) and EDFA gains (assumed in dB) are read from the "edfaPositions_km" and "edfaGains_dB" attributes of the links. The format of both attributes are the same: a string of numbers separated by spaces. The i-th number corresponding to the position/gain of the i-th EDFA. If the attributes do not exist, it is assumed that no EDFAs are placed in this link. EDFA specifications given by "edfa__XXX" parameters
- A set of dispersion compensating modules (DCMs) located in none, one or more positions in the fiber link, separating them in different spans. If a DCM and a EDFA have the same location, it is assumed that the DCM is placed first, to reduce the non-linear effects. DCM positions (as distance in km from the link start to the DCM location) are read from the "dcmPositions_km" attribute of the link, and the same format as with "edfaPositions_km" attribute is expected. If the attribute does not exist, it is assumed that no DCMs are placed in this link. DCM specifications are given by "dcm__XXX" parameters
- At the receiver end, WDM channels in the links are separated using a demultiplexer, with specifications given by "mux__XXX" parameters
- Each channel ends in a receiver, with specifications given by "tp__XXX" parameters
The basic checks performed are:
- Signal power levels are within operating ranges at the mux/demux/edfas/dcms and receivers, both when the link has one single active channel, or when all the "channels__maxNumChannels" are active
- Chromatic dispersion is within the operating ranges in every point of the fiber, and at the receiver.
- Optical Signal to Noise Ration (OSNR) is within the operating range at the receiver.
- Polarization mode dispersion (PMD) is within the operating range at the receiver.
