Orbital angular momentum modes do not increase the channel capacity in communication links
2015 (English)In: New Journal of Physics, ISSN 1367-2630, Vol. 17, 043040Article in journal (Refereed) Published
The orbital momentum of optical or radio waves can be used as a degree of freedom to transmit information. However, mainly for technical reasons, this degree of freedom has not been widely used in communication channels. The question is if this degree of freedom opens up a new, hitherto unused 'communication window' supporting 'an infinite number of channels in a given, fixed bandwidth' in free space communication as has been claimed? We answer this question in the negative by showing that on the fundamental level, the mode density, and thus room for mode multiplexing, is the same for this degree of freedom as for sets of modes lacking angular momentum. In addition we show that modes with angular momentum are unsuitable for broadcasting applications due to excessive crosstalk or a poor signal-to-noise ratio.
Place, publisher, year, edition, pages
2015. Vol. 17, 043040
orbital angular momentum, mode density, spectral efficiency, free-space communication, broadcasting, signal-to-noise ratio, crosstalk
IdentifiersURN: urn:nbn:se:kth:diva-169360DOI: 10.1088/1367-2630/17/4/043040ISI: 000353939200003OAI: oai:DiVA.org:kth-169360DiVA: diva2:820709
QC 201506122015-06-122015-06-122015-06-12Bibliographically approved