Numerical modeling is of paramount importance for the design and characterization of optical transmission systems, including metro networks, long-haul and ultra long-haul terrestrial and submarine communication systems, wavelength-division multiplexed systems, all-optical networks, soliton systems, and optical interconnects. In system simulators, the properties of individual photonic devices (components) can be modeled at different levels, ranging from “black-box” models to measurement-based models and detailed physical models. In addition, in some cases the system simulators are interfaced with device-level modeling software.

Often, when field trials and even laboratory experiments are too expensive, such as in the case of long-haul and submarine systems, numerical simulations play a key role in system design. Existing simulation tools provide a wide range of capabilities, including various advanced input signal modulation formats, realistic sources of noise, dispersion variations in fiber links, nonlinear, dispersive and polarization effects, facilitating detailed studies of signal propagation in realistic transmission systems. Many important output characteristics, such as eye-diagram calculations, BER and Q-factor evaluations, are readily available and can be directly compared to experimental data. Importantly, many individual physical effects and system components can be modified or turned on and off independently in numerical experiments, thus enabling the designer to develop an insight into the impact of various effects on overall system performance, a feature usually unattainable in real experiments.

This section includes a number of freely available (FOCSS developed at TRLabs, LIGHTSIM by Softronix Software, SIMFOCS developed by Dr. Geckeler) and commercial (ModeSYS by RSoft, OptiSYSTEM by Optiwave, OptSim by RSoft, PHOTOSS distributed by P. I. Systemtechnik Jens Lenge, VPItransmissionMaker™ WDM by VPIsystems) packages for transmission system modeling. These packages include extended libraries of photonic components for transmitter, communication channel (fiber/waveguide), amplifier, and receiver design, and extensive output parameter capabilities. In addition to general system simulation software, some software providers (OptiSYSTEM Amplifier Edition by Optiwave, VPIcomponentMakerTM Optical Amplifiers by VPIsystems) offer specialized tools for modeling various types of optical amplifiers, including Erbium Doped Fiber Amplifiers (EDFAs), Semiconductor Amplifiers (SOAs), Raman Amplifiers, and doped fibers. These tools facilitate amplifier design and performance optimization by including a variety of important metrics and detailed models for physical effects, specific to a particular type of amplifier, such as noise figure calculations, gain flattening, spectral hole burning, concentration quenching, and excited-state absorption in EDFAs, or nonlinear effects in doped fibers. Optiwave also offers an OptiSYSTEM Multimode Edition that facilitates the design, analysis and simulation of multimode fiber communication systems primarily used for short-distance communications, such as Local Area Networks (LANs). Another specialized modeling tool that compliments the VPIsystems general system simulator is active photonics software (VPIcomponentMakerTM Active Photonics), allowing the investigation and design of active photonic circuits and advanced semiconductor lasers, including integrated tunable lasers, high-power lasers, fast switches, optical logic, modulators, 2R and 3R regenerators, among others. Finally, VPIsystems also provide a tool for designing the so-called “last mile” (VPItransmissionMakerTMCable Access).

Free software developed by Softronix Software.

LIGHTSIM (previously PC-SimFO) is an easy to use simulator for modeling optical fiber communication systems using a PC.

Capabilities:

Wide range of photonic device models available as icons
Models operate over a wide and continuous spectral bandwidth
Model parameters can be modified easily
Fast and stable algorithms
A complete user friendly hierarchical topology layout environment
Block-oriented waveform simulation
Instrumentation to measure, signal and noise ratio, optical and RF spectra, eye diagrams, bit error rates and optical meters
Simulation includes crosstalk, dispersion, nonlinearities, variations in component parameters
Signal waveforms, eye diagrams, and spectral plots may be viewed at any point in link
Bit error rate (BER) curves may be plotted vs. received optical power or any parameter or user variable in the link
LIGHTSIM library has almost all critical photonics components, including a variety of passive and active optical and electrical component models, semiconductor lasers like multimode Fabry-Pérot lasers and monomode DFB lasers, visualizers to monitor the signal state in the simulation (e.g. eye-diagrams, power meters, etc.)

Applications:

Singlemode and multimode lasers
Signal and noise in a transmission systems
Non linear effects in monomode fibers
Analysis of optical and electrical filters
Direct and coherent optical receivers
Bit error rates in digital transmission
Signal noise ratio in analog transmission
Budget optical power in communication link
WDM and SCM transmission systems
Video transmission systems

Commercial software sold by RSoft.

ModeSYS is a software supporting the design, analysis, and simulation of multimode optical communication systems.

Capabilities:

A variety of launch conditions is supported and the system impact of the launch conditions can be studied since the excitation of the modes in multimode communication systems has a strong effect on the system performance
Temporal and spatial characteristics are modeled
The differential mode delay of a fiber with a given index profile and the effective modal bandwidth of the fiber can be investigated
Effecive integration of system-level and device-level modeling approaches to combine the speed of system-level simulations with the accuracy of device level simulations
A very straightforward system-level analysis
The signal representations in the simulations include both temporal waveforms and spatial modes
Simulations of single- and multi-channel systems utilizing multiplexing techniques such as coarse wavelength division multiplexing are supported
ModeSYS also includes an internal mode solver to enable the simulation of arbitrary index profiles in multimode fibers
ModeSYS also provides interfaces to device-level tools such as BeamPROP for more detailed device-level modeling of multimode components in conjunction with the system simulations
For custom model development, ModeSYS also provides interfaces to third party tools such as MATLAB® and an application programming interface (API) for custom user model development in languages such as C/C++

Applications:

System-level analysis of standardized multimode optical communications technologies such as 1 Gb and 10 Gb Ethernet and Fiber Channel, as well as the study of proprietary optical data communication platforms
Semiconductor lasers
Semiconductor lasers
Multiplexing
Multimode fiber with arbitrary index profiles and profile perturbations
Fiber/fiber and fiber/receiver coupling and offsets
Transceiver/fiber pair encircled flux (EF)
Fiber differential mode delay (DMD)
Modal and chromatic dispersion (MD, CD)
Inter-symbol interference (ISI)
Effective modal bandwidth
Signal analysis
Signal spectra
BER estimation

Related publications:

R. C. J. Hsu et al., “Capacity enhancement in coherent optical MIMO (COMIMO) multimode fiber links,” IEEE Commun. Lett. 10, 195 (2006).
R. C. J. Hsu et al., “Capacity enhancement in coherent optical MIMO (COMIMO) multimode fiber links,” IEEE Commun. Lett. 10, 195 (2006).
J. Morikuni et al., “System simulation of multiplexing methods for multimode local area networks,” OFC/NFOEC 2005 Technical Proceedings, March 2005.
G. Shaulov and Y.Sun, “DMD simulations based on scaled/non-scaled index profiles and comparison with Cambridge model results,” IEEE 802.3aq Interim Meeting, Ottawa, Canada, September 2004.
G. Shaulov and B. Whitlock, “Multimode Fiber Communication System Simulation,” IEEE 802.3aq Plenary Meeting, Portland, Oregon, July 2004.
J. Morikuni et al., A New Multimode Fiber Model for Optical Data Communication System Analysis, 2003 IEEE/LEOS Annual Meeting Conference Proceedings, paper MO3,Tucson, Arizona, October 27, 2003.
J. Morikuni et al., Multimode System Simulation as an Alternative to Spreadsheet Analysis for the Study of Gb/s Optical Communication Systems, 2003 IEEE/LEOS Annual Meeting Conference Proceedings, paper MO4, Tucson, Arizona, October 27, 2003.