Today's fiber optic communications networks typically operate at 1550 nm spectral windows and use erbium-doped fiber amplifiers (EDFAs) to extend communications or to increase the power of wavelength division multiplexing (WDM). However, in order to take advantage of the new spectral window to meet future communication bandwidth requirements and to amplify signals in the 1600-1750 nm spectral region from empty photonic bandgap fibers, a signal that EDFA can not provide, scientists at the Russian Academy of Sciences Optical Fiber Research Center , A bismuth-doped (Bi) fiber amplifier has been developed that uses a commercially available 1550 nm laser diode pump operating at 1640-1770 nm band. Bismuth-doped MCVD fiber Although TDM optical fiber amplifiers (TDAs) can operate at 1700 nm (and up to 1900 nm) windows, low efficiency and strong amplified spontaneous emission (ASE) must be mitigated by various special co-doping and home-made ASE filtering techniques. , Which makes TDFA hard to use for 1700 nm windows. Figure: 1700nm optical amplifier (right) to enlarge self-made multi-wavelength light source (left), the wavelength range of 1615 ~ 1795nm, the wavelength interval of 15nm uniform. The top shows the transmission spectrum of WDM. As an alternative to TDFA, bismuth-doped germanosilicate fibers provide amplification in the 1700 nm band and the research team developed a 1700 nm optical amplifier by developing a special bismuth-doped fiber with high germanium content. In order to obtain the best gain distribution, several optical fibers with different concentrations of doped bismuth cores were fabricated using the Modified Chemical Vapor Deposition (MCVD) method. Bismuth doped fiber amplifier (BDFA) uses bismuth-doped fiber with different doping concentration, cladding layer of 125μm and core diameter of 2μm. Two bidirectional fiber-core pumps are used by two laser diodes with power of 150mW and wavelength of 1550nm Shown). In order to measure the performance of BDFA, a self-made multi-wavelength light source was constructed by using a super-luminescent bismuth-doped fiber source and a high-reflectivity fiber Bragg grating (FBG) to generate 1615~1795 nm uniform spacing (15 nm spacing) spectral lines. 1700nm performance Based on the measurement of various BDFA performance parameters, it is concluded that the optimal doping amount of bismuth is 0.015-0.02% for obtaining the maximum optical gain. An optical amplifier with a 50m bismuth doped fiber provides a maximum gain of 23dB at 1710nm, a 3dB bandwidth of 40nm, a gain efficiency of 0.1dB / mW, and a minimum noise figure of about 7dB. The 3dB gain bandwidth and efficiency of BDFA are better than TDFA. "An important issue is the development of fiber amplifiers in new spectral areas where the optical loss of communications fibers is less than 0.4 dB / km," said Professor Evgeny Dianov, Scientific Director of the Russian Academy of Sciences Optical Fiber Research Center. "This will enable high-speed optical fiber systems It is possible to use the extended spectral region for information transfer, and the development of this amplifier is the first major step in this direction, Dianov added. "In this quest, there is a need to create broadband optical amplifiers with gain bandwidths greater than 100 nm, which will be A new breakthrough in the development of optical fiber communication systems that use these amplifiers and active optical fibers. " Belt Bucket Elevator,Belt Type Bucket Elevator,Discharge Belt Bucket Elevator,Gravity Discharge Belt Bucket Elevator Quantum Conveying Systems Yangzhou Co.,Ltd. , https://www.yzconveying.com