Tham khảo tài liệu 'frontiers in guided wave optics and optoelectronics part 4', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 6 Bismuth-doped Silica Fiber Amplifier Young-Seok Seo and Yasushi Fujimoto Korea Atomic Energy Research Institute Korea 1. Introduction To accommodate rapidly increasing quantities of information and communication optical fiber transmission technology with high-speed high-capacity is demanded. The development of an optical gain medium and fiber amplifiers to cover the 1250 1650 nm region which is the entire optical telecommunication windows of silica fiber becomes an important issue for ultra-wide broadband optical communication. Bismuth-doped glasses exhibit a broadband luminescence in the near infrared region. Thus they are potential gain media for extending the spectral bandwidth of the current erbium-doped silica fiber amplifiers. There are several reports on an infrared luminescence from bismuth-doped glasses such as germanate phosphate borate et al. Meng et al. 2005ab Peng et al. 2005abc Suzuki Ohishi 2006 . According to their research bismuth-doped glasses are therefore very promising for creating broadband amplifiers for fiber telecommunication lines and tunable or femto-second lasers. There are two useful wavelengths for optical communication. One is the 1550 nm erbium-doped fiber amplifiers EDFAs working wavelength which has minimum losses. EDFA developments within the third telecommunication window have contributed to the rapid growth of wavelength division multiplexing WDM transmission systems. The L-band 1570 1605 nm of EDFA can be used in WDM systems in conjunction with C-band 1530 1560 nm . However efforts to use WDM techniques to exploit this capability have been hampered by nonlinear fiber effects such as four-wave mixing. In addition the amplification bandwidth of silica-based EDFA is as small as 70 nm Yamada et al. 1998 . A broadband amplifier with a gain bandwidth of more than 70 nm was reported by the integration of EDFA with thulium-doped fiber amplifiers or fiber Raman amplifiers FRAs Yamada et al. 1998 . The other useful wavelength 1300 nm .
