Development of New Pump Source FRSi4XX Series for Forward Raman Amplifiers

Background

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;^{(note 1)}) is becoming an important factor in soon-to-be-deployed ultrahigh-speed optical fiber communications such as 400 Gbps and beyond. Existing erbium-doped fiber amplifiers (EDFA;^{(note 2)}), which are widely used in current systems, do not have sufficient OSNR performance. Demand is increasing for Raman amplifiers^{(note 3)} due to their excellent noise characteristics. Forward Raman amplifiers, which make the most of the advantages of Raman amplification, are expected to be a technology necessary for increasing transmission distances^{(note 4)}.

In the past, only the backward Raman amplifiers was used due to limitations of the noise characteristics of the pump source. Furukawa Electric’s FRSi4XX Series novel pump sources make it possible to realize forward Raman amplifiers and featuring high output as well as excellent low-noise characteristics.

Details

High power output

Low noise

(Spectral characteristic)

(Noise characteristic)

Glossary

• note 1
  OSNR stands for Optical Signal to Noise Ratio. It is defined as the ratio of optical signal power to optical noise power. Improvements in OSNR contribute to the extension of transmission distances.
• note 2
  EDFA stands for Erbium Doped Fiber Amplifier. An EDFA is an optical fiber amplifier in which erbium is added to the core of the optical fiber. It is currently widely used in wavelength division multiplex (WDM) systems. Wavelengths around 1550 nm can be amplified with excitation light of 980 nm or 1480 nm.
• note 3
  Raman scattering occurs in a wavelength region that is about 100 nm longer than the excitation light wavelength. When an optical signal exists in this scattered light region, it is amplified by stimulated Raman scattering and can be used as an amplifier. Although its excitation efficiency is lower than that of an EDFA, it is widely used because it has excellent features such as a wide amplification band, the ability to amplify an arbitrary wavelength range and low noise interference through the use of optical fiber as an amplification medium. Transmission of excitation light in the same direction as the optical signal is called forward pumping, whereas transmission in the opposite direction as the optical signal is called backward pumping.
• note 4
  Refer to the news release, “Development of New Pump Source Technology for Raman Amplification” published by Furukawa Electric on March 6, 2019.
• note 5
  EOL stands for End of Life.

Furukawa Electric Group’s efforts towards the SDGs

Based on the corporate philosophy of “Drawing on more than a century of expertise in the development and fabrication of advanced materials to contribute to the realization of a sustainable society through continuous technological innovation,” the Furukawa Electric Group is conducting business activities centered on four core technological capabilities (metals, polymers, photonics and high frequency). Moreover, keeping in mind the “Sustainable Development Goals (SDGs)” adopted by the UN, we formulated the “Furukawa Electric Group Vision 2030,” which clarified the business areas of the Furukawa Electric Group, and are advancing efforts aimed at “creating solutions for the new generation of global infrastructure combining information, energy, and mobility to build a sustainable world and make people’s life safe, peaceful, and rewarding.