This course allows students to understand the building blocks required to design a point-to-point fiber optic transmission system in the different parts of an optical fiber network (core, access or local area network). Students become familiar with the architectures of the transmitters and receivers as well as with signal degradations related to propagation in amplified optical systems. They also learn the metrics for estimating the quality of a transmission. They will thus be able to choose and implement the technologies adapted to the targeted transmission link.
L1 – Introduction (3h)
- Overview of the main involved technologies (fibers, direct/external modulations, photo-detection, optical amplification)
- Main limitations: loss, dispersion, noise and non-linear effects
- Overview of transmission system architectures for different reach and rate targets
- Overview of performance metrics (signal to noise ratio, capacity, error rate)
- History of the evolution of optical systems
L2 – Transmitters (3h)
- Laser sources
- Direct modulation and external modulation
- External modulator technologies (focus on electro-refraction)
- Implementation of modulation formats (OOK, PSK, QAM)
- Multiplexing techniques
- Examples and diagrams of transmitters
- Efforts to integrate and reduce energy consumption
L3 – Receivers and optical amplification (3h)
- EDFA, Raman and SOA optical amplification (focus on EDFA)
- Photo-detection and noise contribution at the receiver
- OSNR sensitivity (optical signal-to-noise ratio)
- Reduction of amplifier noise factor
- Efforts to improve OSNR sensitivity
L4 – Propagation (6h)
- Fibers: linear effects (loss, CD, PMD)
- Fibers: non-linear effects (mainly Kerr effect)
- Passive and active optical elements : PDL in ROADMs and in amplifiers
- Propagation channel dynamics: variation and accumulation of random effects
- Dimensioning of a transmission link
L5 – Coherent-detection based systems (1h30)
L6 – Direct-detection based systems (1H30)
Lab1 – Numerical simulation of transmitters and receivers (3h)
Lab2 – Coherent Detection (3h)
Lab3 – Bit error rate measurements in IM-DD systems (3h)
Lab 4 – Numerical simulation of optical fiber transmission lines (3h)
Lab demos – Examples of high rate transmissions and associated digital signal processing (3h) – VOLUNTARY
Knowledge test – written exam (2h)