The laboratory of high power laser optical components of the Shanghai Institute of Optics and Fine Mechanics (SIOM) of the Chinese Academy of Sciences (CAS) prepared the first low-loss Bi/P co-doped silica fiber and achieved optical amplification in the E-band. Related research results were published in the Chinese Optics Letters under the title "High gain E-band amplification based on the low loss Bi/P co-doped silica fiber" on June 25, 2022.

With the rapid development of the Internet, cloud computing, Internet of Things and other technologies, the rapid increase in the amount of information has put forward higher requirements for the transmission capacity of optical fiber communication systems, and the traditional erbium-doped optical fiber amplifier (EDFA) working in the C+L band can no longer meet the future communication needs. In recent years, bismuth doped fibers with ultra-wideband near-infrared luminescence characteristics have become the focus of attention in this field.

The research team prepared low-loss Bi/P co-doped silica fibers using the modified chemical vapor deposition (MCVD) techni que combined with the solution doping method, where the background loss was as low as 17dB/km. The team built a fiber amplifier based on this homemade fiber and systematically compared the gain performance of the amplifier under different pump methods and pump wavelengths, as well as the relationship between fiber length, pump power, signal power, and gain. Using the bidirectional pumping method, the maximum gain of 190m long bismuth fiber at 1355nm is close to 20dB, and the minimum NF is 4.6dB with the pump wavelength of 1240nm, the total pump power of 870mW, and the signal power of -30dBm.

Fig. 1. (a) Background loss and (b) absorption spectrum of the BPDF. (Image by SIOM)

Fig. 2. Experimental setup of the single stage BPDF amplifier. (Image by SIOM)

Fig. 3. Gain and NF characteristics under bidirectional pumping with two 1240 nm LDs. (Image by SIOM).

Article website:
https://doi.org/10.3788/COL202220.100602

Contact:
WU Xiufeng
General Administrative Office
Shanghai Institute of Optics and Fine Mechanics, CAS
Email: xfwu@siom.ac.cn
Web: http://english.siom.cas.cn/