RP Fiber Power – Simulation and Design Software for Fiber Optics, Amplifiers and Fiber Lasers

Mode Solver

The software contains a highly efficient LP mode solver, which can calculate the amplitude profiles, effective mode areas, cut-off wavelengths, propagation constants, group velocities and chromatic dispersion of all guided fiber modes from a given radially symmetric refractive index profile. This is very useful both for models with passive and active fibers – even for cases with thousands of modes.

For example, the mode solver is utilized in case studies on the modes of a parabolic index fiber, the mode structure of multimode fibers and on dispersion engineering for telecom fibers.

See our demo video for using the mode solver.

Numerical Beam Propagation

RP Fiber Power can propagate optical fields with arbitrary complex amplitude distributions through fibers (or other waveguides, laser crystals, free space, ...) with arbitrary weakly guiding refractive index profiles. The fiber may be bent (with arbitrarily varying bend radius), tapered, exhibit random index variations, etc. – there is a huge range of opportunities for a wide range of research topics.

Example cases show the evolution of light for a misaligned input beam, pump absorption in double-clad fibers, and the behavior of light in a tapered region of a fiber.

A convenient interactive beam profile viewer allows you easy inspection of any calculated beam profiles.

Laser-active Ions

For simulating fiber amplifiers and fiber lasers, the detailed behavior of laser-action ions needs to be included.

Normally, one works with the simple standard gain model. For more complicated laser ions, however, it is possible to freely define energy level schemes of laser-active ions and a great variety of processes inducing transitions between these levels. Therefore, the software is applicable to any conceivable laser ions (Nd³⁺, Yb³⁺, Er³⁺, Tm³⁺, Pr³⁺, …) and pumping schemes. It can even handle cases with different ion species combined (e.g. Yb³⁺ and Er³⁺) or with complicated quenching processes. It can also describe upcon­version lasers of various kinds.

Multiple Pump Waves, Signals, and ASE

You can define a large number of so-called optical channels for pump waves, signals and amplified spontaneous emission (ASE). Each channel may represent either a single propagation mode or some (possibly large) collection of modes. One can freely define its transverse intensity distribution, or simply use the mode intensity distributions from calculated fiber modes. The software is also suitable for modeling devices based on double-clad fibers. For lasers, both linear and ring configurations are possible.

The software can calculate the distribution of all optical powers and excitation densities in the steady state (and within dynamic models, see below) with an amazing speed and high reliability. The sophisticated algorithms allow that even in complicated cases. (With other software, you might easily have much longer computation times and convergence issues in complicated situations.)

Dynamic Simulations

The software can also simulate the temporal evolution of optical powers and excitation densities – both with power propagation and beam propagation. For example, it can simulate the distortion of an optical pulse by gain saturation during amplification in a fiber amplifier (see the figure). It can also simulate the pulse generation in a Q-switched fiber laser or even a bulk laser. Dynamic simulations are possible both with propagation only of optical powers and with propagation of full beam profiles.

All this can be done with uttermost flexibility. For example, you can freely define the time dependencies of the powers of pump and input signal waves, and illustrate the results as you like: display how the values evolve within a pulse, show how the pulse parameters evolve for multiple pulses, etc.

Ultrashort Pulse Propagation

The software can simulate the propagation of ultrashort pulses in passive and active fiber devices, and also in other components such as spectral filters, manually or automatically optimized dispersive compressors, prism pairs and grating pairs, modulators and saturable absorbers. One may thus model not only single-pass amplification in a fiber amplifier or data transmission in a telecom fiber cable, but also the pulse evolution in mode-locked fiber lasers, chirped-pulse amplifier systems, regenerative amplifiers and fiber interferometers. The interactive pulse display window allows one to conveniently inspect all details of the pulses, in addition to many kinds of diagrams.

The temporal and spectral pulse properties can evolve in a fiber under the influence of arbitrary chromatic dispersion (which may be obtained from the mode solver), the Kerr nonlinearity, stimulated Raman scattering (SRS) and amplifier gain (including gain saturation). Self-steepening can be included; even supercontinuum generation can be simulated. A refined numerical algorithm with automatic step size control ensures a high accuracy combined with high speed.