Long-Haul Optical Transmission Link

Researchers from Chalmers Univer­sity of Tech­nology, Sweden, and Tallinn Uni­versity of Tech­nology, Estonia, have demon­strated a 4000 kilometre fiber-optical trans­mission link using ultra low-noise, phase-sensi­tive optical amplifiers. This is a reach improve­ment of almost six times what is possible when using conven­tional optical amplifiers.

Signal constellation diagrams comparing conventional amplification and phase-sensitive amplification in an amplifier noise limited regime and a fibre nonlinearity limited regime. (Source: S. Olsson)

Video streaming, cloud storage and other online services have created an insatiable demand for higher trans­mission capacity. To meet this demand, new techno­logies capable of signi­ficant improve­ments over existing solutions are being explored worldwide. The reach and capacity in today’s fibre optical trans­mission links are both limited by the accumu­lation of noise, origi­nating from optical ampli­fiers in the link, and by the signal distortion from nonlinear effects in the trans­mission fiber. In this ground-breaking demon­stration, the researchers showed that the use of phase-sensitive amplifiers can signi­ficantly, and simul­taneously, reduce the impact of both of these effects.

“While there remain several engi­neering challenges before these results can be implemented commercially, the results show, for the first time, in a very clear way, the great benefits of using these ampli­fiers in optical communi­cation”, says Peter Andrekson, who leads the research on optical communi­cation at Chalmers Univer­sity of Tech­nology. The amplifiers can provide a very signi­ficant reach improve­ment over conven­tional approaches, and could poten­tially improve the performance of future fiber-optical communi­cation systems.

“Such amplifiers may also find appli­cations in quantum infor­matics and related fields, where gene­ration and processing of quantum states are of interest, as well as in spectro­scopy or any other appli­cation which could benefit from ultra-low-noise amplifi­cation”, says Andrekson. (Source: Chalmers Univ.)

Reference: S. L. I. Olsson et al.: Long-haul optical transmission link using low-noise phase-sensitive amplifiers, Nat. Commun. 9, 2513 (2018); DOI: 10.1038/s41467-018-04956-5

Links: Dept. of Microtechnology and Nanoscience, Chalmers University of Technology, Gothenburg, Sweden • Thomas Johann Seebeck Dept. of Electronics, Tallinn University of Technology, Tallinn, Estonia

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