Case Studies
Our case studies nicely complement the tutorials and encyclopedia articles. Each one provides a quantitative analysis of a concrete case of practical importance. Dive into these studies to improve your understanding of the physics and technology background and of suitable methods to investigate such things. You may also get inspired for further work.
You may deselect some topics to more easily find what is of interest to you:
| modes | dispersion | telecom | amplifiers |
| lasers | ASE | pulses | video |
Mode Structure of a Multimode Fiber
We explore various properties of guided modes of multimode fibers. We also test how the mode structure of such a fiber reacts to certain changes in the index profile, e.g. to smoothing of the index step.
#modes
Number of Modes of a Highly Multimode Fiber
We seek a simple equation for estimating for the number of modes of a highly multimode fiber, which can be applied to fiber designs with arbitrary shapes of the refractive index profile. Instead of applying complicated mathematics, we build a hypothesis and subject that to multiple numerical tests.
#modes
The Numerical Aperture of a Fiber: a Strict Limit for the Acceptance Angle?
The requirement of total internal reflection would seem to set a strict limit for the angular distributions of fiber modes. However, some modes are found to exceed that limit significantly. We investigate that in detail for single-mode, few-mode and multimode fibers.
#modes#video
Dispersion Engineering for Telecom Fibers
We explore different ways of optimizing refractive index profile for specific chromatic dispersion properties of telecom fibers, resulting in dispersion-shifted or dispersion-flattened fibers. This also involves automatic optimizations.
#modes#dispersion#telecom#video
Telecom Fiber With Parabolic Index Profile
We investigate how intermodal dispersion of a multimode fiber can be minimized with a parabolic doping profile.
#modes#telecom
Erbium-doped Fiber Amplifier for a Long-wavelength Signal
Amplified spontaneous emission (ASE) turns out to be a limiting factor, requiring a dual-stage amplifier design.
#amplifiers#ASE#telecom#video
Erbium-doped Fiber Amplifier for Rectangular Nanosecond Pulses
We deal with deformations of the pulse shape due to gain saturation. These can be minimized by pre-distorting the input pulses.
#amplifiers#pulses#video
Erbium-doped Fiber Amplifier for Multiple Signals
We optimize an amplifier for equal output powers of signals spanning a substantial wavelength range. There is a trade-off between power efficiency and noise performance.
#amplifiers#telecom
ASE in Ytterbium-doped Fibers
We study various aspects of amplified spontaneous emission (ASE) in ytterbium-doped fibers — for example, why it is different in forward and backward directions, how the fiber length can have a crucial impact, and how the fiber core diameter matters.
#amplifiers#ASE
Designing a Double-clad Fiber Amplifier
We develop a double-clad fiber amplifier with high gain, where we have to care about limiting losses by ASE.
#amplifiers#ASE
Ytterbium-doped 975-nm Fiber Lasers
We explore how to realize Yb-doped fiber lasers emitting at the tricky wavelength of 975 nm. This turns out to be challenging for devices with double-clad fibers due to ASE at longer wavelengths.
#lasers#ASE#video
Nonlinear Pulse Compression in a Fiber
We explore how we can spectrally broaden light pulses by self-phase modulation in a fiber and subsequently compress the pulses using a dispersive element. A substantial reduction in pulse duration by more than an order of magnitude is easily achieved, while the pulse quality is often not ideal.
#pulses#nonlinearities
Parabolic Pulses in a Fiber Amplifier
We explore the regime of parabolic pulse amplification in an Yb-doped single-mode fiber. We find suitable system parameters and investigate limiting effects.
#amplifiers#pulses#nonlinearities
Numerical Experiments With Soliton Pulses in Fibers
We investigate various details of soliton pulse propagation in passive fibers, using numerical simulations.
#pulses#nonlinearities
Collision of Soliton Pulses in a Fiber
We let two soliton pulses collide in a fiber. Surprisingly, they survive such collisions, even if we involve solitons of higher order.
#pulses#nonlinearities
Soliton Self-frequency Shift in Glass Fibers
We numerically simulate the soliton self-frequency shift, which is caused by stimulated Raman scattering. Influences like higher-order dispersion are found to be quite relevant.
#pulses#nonlinearities
Soliton Pulses in a Fiber Amplifier
We investigate to which extent soliton pulses could be amplified in a fiber amplifier, preserving the soliton shape and compressing the pulses temporally.
#amplifiers#pulses#nonlinearities
Raman Scattering in a Fiber Amplifier
We investigate the effects of stimulated Raman scattering in an ytterbium-doped fiber amplifier for ultrashort pulses, considering three very different input pulse duration regimes. Surprisingly, the effect of Raman scattering always gets substantial only on the last meter, although the input peak powers vary by two orders of magnitude.
#amplifiers#pulses#nonlinearities
Chirped-pulse Ytterbium-doped Fiber Amplifier System
We design an ytterbium-doped chirped-pulse fiber amplifier system. We investigate how the remaining nonlinear effects limit the possible performance parameters.
#amplifiers#pulses#video
Supercontinuum Generation in a Germanosilicate Single-mode Telecom Fiber
We explore supercontinuum generation in telecom fibers. This works well for wavelengths beyond the zero dispersion wavelength. For operation with shorter-wavelength pulses, other fibers are required.
#pulses#video
Smaller Case Studies
We have various smaller case studies made with our simulation and design software: