Phase Sensitive Optical Amplifiers to extend Fibre Optical Transmission
It is possible to extend the fibre optical data transmission links by optical amplifiers. This was shown by the Estonian and Swedish researchers by using the new phase-sensitive amplifiers (PSAs). The extent of reach is almost six times that which is possible when the conventional optical amplifiers are used.
The extent of reach and capacity of the current fibre optical data transmission links have certain limitations. This is mainly due to the noise accumulation that originates from the optical amplifiers in the link and signal distortion that occurs from nonlinear effects in the transmission fibre. Both these problems can be considerably reduced when phase sensitive amplifiers (PSAs) are used.
The researchers from Chalmers University of Technology, Sweden and Tallinn University of Technology, Estonia, have shown that there is a six time increase in the extent of reach as compared with the conventional optical amplifiers. They have shown a 4000 km fibre-optical transmission link using ultra low noise, phase sensitive optical amplifiers. Their findings have been published in Nature Communications.
The researchers used a multi-channel compatible and modulation-format independent transmission link with in-line PSAs. They showed that there is a reach improvement of 5.6 times at optimal launch power using the phase sensitive optical amplifiers operating at an accumulated non-linear phase shift of 6.2 rad. There were two data-carrying waves that were transmitted and they occupied twice the bandwidth. Twice the total power was propagated as compared to the phase-insensitively amplified link.
These results that were obtained showed that when the in-line phase sensitive optical amplifiers which offer low-noise amplification and non-linear mitigation are used, they could provide nonlinear tolerance and also a greater transmission reach.
Professor Peter Andrekson who is heading the research on optical communication at Chalmers University of Technology says that there are great advantages and benefits in using these phase sensitive optical amplifier in optical communication. There are a few engineering challenges that need to be overcome before these results can be used commercially.
In today’s day and age there is a great demand for higher transmission capacity. This is seen in video streaming, cloud storage and other online services which require high transmission capacity. In order to meet this demand, new technologies need to be explored. The technologies are being explored the world over to find solutions that will have significant improvements over those that are currently in existence. The phase sensitive optical amplifiers can provide a great amount of reach improvement over the conventional optical amplifiers. This will enhance the performance of future fibre optical communication systems. These optical amplifiers can be used to serve the purpose of the increasing demands of higher transmission capacity.
These phase sensitive optical amplifiers can also be used in quantum informatics and related areas, wherein the generation and processing of quantum states are involved. The ultra-low noise amplifiers can play a vital role in spectroscopy or other applications.
This research has received funding from the European Research Council (ERC), the Swedish Research Council and the Wallenberg Foundation.
