Optics in Communication

Prof. Dr. Schmauss, 5 ECTS

Optical data transmission systems are the enabler for our modern communication networks. Since the first systems have been installed, the transmission capacity as well as the transmission distance has been increased dramatically. The migration from point-to-point transmission systems to complex optical networks is still in progress. The fast evolution of optical transmission technology is stimulated by innovations in the field of the system key components. The lectures concentrate on the physical effects and properties of key components like semiconductor lasers, optical modulators, optical fibers, optical amplifiers and detector diodes. Especially also the nonlinear effects of the transmission fiber are discussed. The main focus is on the effects and characteristics which are important to achieve a certain system performance. The influence of component parameters on system performance is presented in examples related to installed systems and systems that are actually in development. The exercises partly use a numerical simulation tool to analyze the component influence on system performance.

Prof. Dr. C. Marquadt, 5 ECTS

In this module we will introduce and discuss fundamental concepts of quantum communication and talk about recent developments. Topics include: Introduction to quantum information concepts, quantum optics: preparation and measurement of quantum states, concepts of quantum cryptography and the BB84 protocol, quantum key distribution with discrete variables: modern protocols, QKD with continuous variables, modern quantum key distribution security proofs, quantum repeaters, quantum communication with satellites, quantum random number generation

After the module students

• comprehend an interesting physical topic in a short time frame
• identify and interpret the appropriate literature
• select and organize the relevant information for the presentation
• compose a presentation on the topic at the appropriate level for the audience
• use the appropriate presentation techniques and tools
• criticize and defend the topic in a scientific discussion

Prof. Dr. Chekhova, 5 ECTS

• Basic concepts of statistical optics
• Spatial and temporal coherence. Coherent modes, photon number per mode
• Intensity fluctuations and Hanbury Brown and Twiss experiment
• Interaction between atom and light (semiclassical description)
• Quantization of the electromagnetic field
• Quantum operators and quantum states
• Heisenberg and Schrödinger pictures
• Polarization in quantum optics
• Nonlinear optical effects for producing nonclassical light
• Parametric down-conversion and four-wave mixing, biphotons, squeezed light
• Single-photon states and single-photon emitters
• Entanglement and Bell’s inequality violation

Prof. Dr. Joly, Dr. Fattahi, 5 ECTS

• Linear properties of materials.
• Origin of the nonlinear susceptibility.
• Importance of phase-matching.
• Second harmonic generation, derivation of the set of coupled equations.
• Importance of the initial phase and case of seeding second harmonic generation. Use of birefringence to achieve phase-matching.
• Electro-optic effects.
• Nonlinear process in relation to third order nonlinearity.
• Modulation instability, soliton formation, perturbations of soliton, and supercontinuum generation.
• Application: nonlinear optics in photonic crystal fibers.

Prof. Dr. Joly, Dr. Fattahi, Prof. Dr. Chekhova, 5 ECTS

• Nonlinear propagation in solid-core photonic crystal fibres (modulation instability, four-wave mixing, soliton dynamics, supercontinuum generation) and in hollow-core photonic crystal fibres (generation of tunable dispersive waves, plasma in fibres)
• Nonlinear optical effects (parametric down-conversion, four-wave mixing, modulation instability) for the generation of nonclassical light (entangled photons, squeezed light, twin beams, heralded single photons).
• Nonlinear effects for generating high energy sub cycle pulses (kerr-lens mode-locking, Yb:YAG laser technology, optical parametric amplification, pulses synthesis, attosecond pulse generation)

Prof. Dr. Schmauss, 5 ECTS

• Multiplex Techniques: electrical / optical time division multiplexing, wavelength division multiplexing
• Dispersion Management: dispersion and bitrate, dispersion compensation, dispersion in WDM systems
• Noise and Power Management: power budget, OSNR management, OSNR calculation
• Management of Nonlinearities: self & cross phase modulation (SPM / XPM), four wave mixing (FWM), Raman scattering, solitons
• Spectral Efficiency: definition, increase of spectral efficiency
• Modulation Formats:intensity modulation, multilevel transmission, CS-RZ, SSB Transmission, DPSK, DQPSK, Coherent Transmission
• Optical Regeneration: 2R-Regeneration by nonlinearities, distributed regeneration, 3R-Regeneration

Prof. Dr. Schmauss, Prof. Dr. Joly, 5 ECTS

• Guidance mechanism (geometric and EM approaches)
• Photonic crystal fibres (solid-core, hollow-core, bandgap and anti-resonance fibres)
• Nonlinear optics effect in optical fibres
• Applications

Prof. Dr. C. Marquadt, 5 ECTS

In this module we will introduce and discuss fundamental concepts of quantum communication and talk about recent developments. Topics include: Introduction to quantum information concepts, quantum optics: preparation and measurement of quantum states, concepts of quantum cryptography and the BB84 protocol, quantum key distribution with discrete variables: modern protocols, QKD with continuous variables, modern quantum key distribution security proofs, quantum repeaters, quantum communication with satellites, quantum random number generation

After the module students

• comprehend an interesting physical topic in a short time frame
• identify and interpret the appropriate literature
• select and organize the relevant information for the presentation
• compose a presentation on the topic at the appropriate level for the audience
• use the appropriate presentation techniques and tools
• criticize and defend the topic in a scientific discussion