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11 March 2020

Furukawa develops pump source for forward Raman amplifiers, boosting speed and extending reach

Furukawa Electric Co Ltd (FEC) of Tokyo, Japan has developed FRSi4XX Series pump sources for forward Raman amplifiers that extend transmission distances in ultra-high-speed optical fiber communications further than conventional systems.

Proliferation of smartphones has led to a dramatic increase in communication traffic, including the expansion of wireless backbones, cloud computing, video streaming and the penetration of social networks. To deal with this traffic explosion, improvement in optical signal-to-noise ratio (OSNR) is becoming an important factor in soon-to-be-deployed ultra-high-speed optical fiber communications such as 400Gbps and beyond. Existing erbium-doped fiber amplifiers (EDFA), which are widely used in existing systems, do not have sufficient OSNR performance. Demand is increasing for Raman amplifiers due to their excellent noise characteristics. Forward Raman amplifiers, which make the most of the advantages of Raman amplification, are expected to be necessary for increasing transmission distances.

In the past, only the backward Raman amplifier was used due to limitations of the noise characteristics of the pump source. Furukawa Electric says that its new FRSi4XX Series pump sources make it possible to realize forward Raman amplifiers and feature high output as well as excellent low-noise characteristics.

The important characteristics of these products are high power output and low noise. Furukawa Electric says that it achieved these characteristics by leveraging the design, manufacturing technology and high-precision packaging of its indium phosphide (InP) optical semiconductor chip. The result is a pump source with a high-output chip structure and high-efficiency coupling technology. The optical output of 100mW or more was achieved through an optimized heat dissipation design.

Operating at wavelengths of 1420-1500nm with wavelength spectrum width of >25nm, the FRSi4XX pump series reduces noise by about 20dB/Hz compared with conventional pump sources for Raman amplifiers.

Combining the FRSi4XX Series with the existing FOL1439 Series yields pump sources especially well suited to forward pumping Raman amplifiers, reckons the firm.

Furukawa Electric says that, as demand for ultra-high-speed optical fiber communications continues to grow, it will further enhance the technology of this series and contribute to the construction of information and communications infrastructure in anticipation of the advancement of 5G. Sample shipments of the FRSi4XX Series are scheduled to begin in second-half 2020.

Tags: Optical communications