Optical field encryption for secure transmission of data

Colin Fraser, Andrew R. Harvey

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


The growing awareness of the vulnerability of information transmitted on communication systems within the government, military and commercial sectors, has stimulated a number of areas of research within the optical community to design optical hardware encryption systems providing inherent immunity to espionage techniques. This paper describes a hardware optical encryption technique that utilises off the shelf telecommunication equipment and negates the necessity for an independent key distribution system with respect to the data transmission system, as is common with alternative encryption system implementations. This method also lends itself easily to fiber optic or free space communication and is applicable within any optical waveband. The encryption-decryption of the optical signal is achieved through low coherence optical interferometry. This requires the instantaneous processing and analysis of the signal, optically, to retrieve the relevant optical phase information hidden in the transmitted optical noise. This technology allows an authorised user to transmit encrypted information at a high data rate securely, while maintaining opaqueness to an unauthorised observer that data transmission is occurring. As the instantaneous optical field properties of the signals present in the system are essential to the optical encryption - decryption process, the system is inherently protected against electronic recording and advances in computational decryption algorithms. For organisations wishing to protect sensitive data and levels of communication activity these are highly desirable features.

Original languageEnglish
Article number10
Pages (from-to)89-96
Number of pages8
JournalProceedings of SPIE - the International Society for Optical Engineering
Publication statusPublished - 2004
EventAdvanced Free-Space Optical Communications Techniques and Technologies - London, United Kingdom
Duration: 27 Oct 200428 Oct 2004


  • Free space communication
  • Hardware security systems
  • Multi-wavelength communication
  • Optical encryption


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