Author biographies xvii co-authored more than 40 publications in scientific journals and conference proceedings and five patents in this field of investigations. Malte.Schneiders@telekom.de CHAPTER 12. OPTICAL AMPLIFIER FOR MAINTENANCE FRIENDLY FIBER NETWORKS (GLENN A. WELLBROCK AND TIEJUN J. XIA) Glenn Wellbrock is the Director of Optical Transport Network Architecture and Design at Verizon, where he is responsible for the development of new technologies for both the metro and long haul transport infrastructure. In addition to his 20+ years at Verizon (1984-2001 & 2004-present), Glenn worked at Marconi and Qplus Networks. glenn.wellbrock@verizonbusiness.com Dr. Tiejun J. Xia is a Distinguished Member of Technical Staff at Verizon. He was a faculty member at the University of Michigan. He holds his Ph.D. degree from the University of Central Florida, M.S. degree from Zhejiang University, and B.S.