polarisatiemultiplexing

Polarization multiplexing, also known as polarisatiemultiplexing in Dutch, is an optical communications technique that uses the two orthogonal polarization states of light to carry independent data streams on a single optical carrier. By encoding one data stream on one polarization and a second stream on the orthogonal polarization, it effectively doubles the data-carrying capacity of a fiber channel without increasing spectral bandwidth.

In modern fiber links, both polarization components are detected with a coherent receiver that employs digital signal processing to separate the polarizations and to compensate polarization effects. Dual-polarization formats such as DP-QPSK and DP-16QAM are commonly used, often in combination with wavelength-division multiplexing to achieve high aggregate data rates. The approach relies on precise polarization demultiplexing and robust equalization to mitigate cross-polarization coupling.

Key challenges include polarization mode dispersion, birefringence, and polarization-dependent loss, which can cause the polarization states to drift and mix over distance. Dynamic polarization tracking and DSP-based compensation are essential for maintaining signal integrity, especially in long-haul and high-data-rate systems. System designers also consider fiber design, optical components, and error-correction coding to maximize reliability.

Polarization multiplexing is widely deployed in backbone networks and data-center interconnects, contributing to the scaling of 100 Gbit/s and higher transmission rates. It is typically combined with other multiplexing strategies, such as WDM and advanced modulation formats, and is supported by international standards and commercial coherent transceivers.