Key Aspects:

  • Optical networks serve as the backbone of today’s internet due to their ability to meet the rising demand for higher bandwidth.
  • These networks have evolved from single-mode systems with megabyte-level bandwidth to systems capable of multiple petabytes per second.
  • Growing data transmission over these networks necessitates enhanced information security for future data networks.
  • Quantum encryption is a potential solution but involves complex implementation.
  • We are investigating the transmission properties of Multimode Fibers (MMF) to achieve equivalent encryption at the transport layer.
  • Information security must not solely rely on cryptographic algorithms, which can be broken with sufficient computational power.
  • Our focus is on an information-theoretically secure approach that ensures security independent of attackers‘ capabilities and resources.

Research Process:

  • We begin by examining a single MMF connection between two network nodes (Alice to Bob).
  • The goal is to leverage MMF transmission properties to give legitimate nodes an advantage over attackers.
  • Measurement of the MMF’s transmission matrix is conducted at the Measurement and Sensor Systems Technology (MST) department to characterize the channel.
  • All modes guided by the fiber are sequentially excited at the input, and the superposition of modes at the output is measured.
  • Influences of various parameters such as fiber bending on the transmission matrix are investigated to determine optimal physical conditions.

Utilization of Matrices:

  • Matrices obtained are used by the Theoretical Communications Engineering (TNT) department to create a channel model.
  • The unknown mode coupling within the fiber is exploited to provide an advantage for Alice and Bob.
  • Various precoding and wiretap coding techniques, along with the addition of artificial noise, are employed to further enhance security.

Validation and Strengths:

  • The best configuration is then tested in a demonstration experiment to validate information-theoretic security in MMF systems using spatial multiplexing.
  • The strength of this proposal lies in the collaboration between MST and TNT, combining their expertise to successfully execute the project.

More Projects on: Click Here