Passive Fibers
Definition: optical fibers without laser-active dopants in the fiber core
More general term: optical fibers
More specific terms: step-index fibers, graded-index fibers, polarization-maintaining fibers, silica fibers, fluoride fibers, mid-infrared fibers, single-crystal fibers, plastic optical fibers, dispersion-shifted fibers, dispersion-decreasing fibers, photonic crystal fibers, photonic bandgap fibers, hollow-core fibers, nanofibers, single-mode fibers, single-polarization fibers, few-mode fibers, multimode fibers, large-core fibers, large mode area fibers, tapered fibers, telecom fibers, specialty fibers
Opposite term: active fibers
German: passive Fasern
Category: 
fiber optics and waveguides
Author: Dr. Rüdiger Paschotta
Cite the article using its DOI: https://doi.org/10.61835/qie
Get citation code: Endnote (RIS) BibTex plain textHTML
Passive fibers are optical fibers without laser-active dopants in the fiber core. That usually implies that they can only passively transmit light, with some propagation losses are without amplification of the optical power. In some cases, however, nonlinear amplification mechanisms based on stimulated Raman scattering or the Kerr nonlinearity occur.
Passive fibers can be separated into many specific categories:
- by fiber materials: glass fibers, single-crystal fibers, polycrystalline fibers (→ mid-infrared fibers), silica fibers, fluoride fibers, plastic optical fibers
- by fiber designs and physical principles of light guiding: step-index fibers, graded-index fibers, photonic crystal fibers, photonic bandgap fibers, hollow-core fibers, large-core fibers, tapered fibers, nanofibers
- by their guiding properties: single-mode fibers, polarization-maintaining fibers, single-polarization fibers, few-mode fibers, multimode fibers, large mode area fibers, dispersion-shifted fibers, dispersion-decreasing fibers
- by the spectral region: near-infrared fibers, mid-infrared fibers, UV fibers
- by their application areas: delivery fibers, telecom fibers, imaging fibers (e.g. as fiber bundles), sensor fibers (→ fiber-optic sensors)
Compared with active fibers, passive fibers generally exhibit lower propagation losses and are available at lower cost.
Fibers may be equipped with fiber connectors and protective materials to form fiber cables.
Passive Fiber Optics
This is a comprehensive introduction to fiber optics, focusing on passive (non-amplifying) fibers. It explains basic principles as well as practical aspects.
Case Study: 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 of the index profile, e.g. to smoothening of the index step.
Case Study: 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.
Case Study: 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.
Case Study: Numerical Experiments With Soliton Pulses in Fibers
We investigate various details of soliton pulse propagation in passive fibers, using numerical simulations.
Case Study: 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.
Case Study: 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.
Case Study: 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.
More to Learn
- Case Study: Mode Structure of a Multimode Fiber
- Case Study: Dispersion Engineering for Telecom Fibers
- Case Study: Nonlinear Pulse Compression in a Fiber
- Case Study: Numerical Experiments With Soliton Pulses in Fibers
- Case Study: Collision of Soliton Pulses in a Fiber
- Case Study: Soliton Self-frequency Shift in Glass Fibers
- Case Study: Soliton Pulses in a Fiber Amplifier
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