Optical link performance calculator based on the Polynomial Closed-Form GN/EGN model (PCFM) v2.2

Optical link performance calculator based on the Polynomial Closed-Form GN/EGN model (PCFM)

The main file is Matlab, the others are mostly MEX files, compiled for Windows/Intel systems and for Linux systems.

The software is capable of fully characterizing the GSNR of each channel of a multi-band, multi-span link, in the presence of ISRS and Raman amplification (both forward and backward). 

Version 1.1: the graphical output of the provided use-case example has been improved. More information is provided, including a breakdown of NLI into SCI and XCI. A dialog lets you choose which span output, of the provided 10-span example of a C+L+S systems, you are interested in.

Version 1.2: several new system examples have been added. Now the full suite of examples include:

• a 1000 km C+L+S system with Raman amplification optimized for throughput (same as in Version 1.1)
• a 1000 km C+L+S system with Raman amplification optimized for throughput and GSNR flatness (new)
• a 3000 km C+L system with Raman amplification optimized for throughput (new)
• a 3000 km C+L system with Raman amplification optimized for throughput and for GSNR flatness (new)
• a 7000 km C-band system optimized for throughput (new)

Version 2.0:

• The SCI (single-channel interference, or SPM) computing module has been entirely re-written to enable operation at lower dispersion and lower symbol rates than before.
• Double Rayleigh Back-scattering (DRB) has been added to all system configurations. It is now a component of the GSNR which shows up in the GSNR plots. In Raman-amplified systems it may be important (see for instance the system example “CLS_1000km_max_throughput”).
• ASE from all Raman effects (both amplification with pumps and ISRS) is taken into account.
• The software now checks for too-low values of dispersion and too-low symbol rates.
  If either or both of these conditions are detected:
  • |β2| < 1 ps^2/km (or approximately |D| < 0.8 ps/(nm km)) at any frequency in the WDM band
  • the symbol rate of any channel in the system is below 7 GBaud

           then the program stops and warns you about it.

Version 2.1:

• CPU parallelism exploited
• 3x speed-up on a 16 core 24 thread machine compared to v2.0, with additional cores or threads providing further improvements
• no use of GPU for now, but future versions may do that

Version 2.2:

• This release introduces PCFM2, a new modeling framework.
• The previous framework used in earlier releases is now referred to as PCFM1.

     Key Improvements: 

• The NLI spectrum is calculated at any frequency, rather than assuming a flat NLI equal to the value at the center frequency of the channel under test
• The contribution from any island is evaluated, including SCI, XCI and MCI
• Machine-learning-based correction factors are not used
• It supports low-symbol rates and any dispersion, including zero dispersion
• The coherence accumulation of NLI across spans are exactly modelled.

      Validation and Examples: 

• An example using PCFM2 is provided in the folder ‘ECOC_subcarrier_NLI_PSD’:
  • It computes the NLI PSD in a subcarrier-based system along a single span, accounting for all the improvements above
  • It provides the full NLI PSD across all subcarriers, instead of only one-subcarrier NLI PSD in Test 2 of the submitted ECOC paper (in the folder ‘paper’)

• Validation tests for the updated coherent accumulation model are available in:
  • The arXiv paper (PCFM2_arxiv.pdf, in the folder ‘paper’)
  • The submitted ECOC paper