Electronics Letters, vol. 24, No. 1, Jan. 7, 1988, pp. 36-38, Hitchin-Herts, GB; N. A. Olsson et al.: "400 Mbits/s, 372 km Coherent Transmission Experiment Using In-Line Optical Amplifiers". |
Proceedings of the 15th European Conference on Optical Communications, vol. 3, Sep. 10th-14th, 1989, Post-Deadline Papers, pp. 42-45, Gothenburg, S. E.; A. Righetti et al.: "An 11 Gbit/sec, 260 km Transmission etc.". |
Electronics Letters, vol. 25, No. 9, Apr. 27, 1989, pp. 594-595, Stevenage, Herts GB; K. Inoue et al., "Mutual Signal Gain . . . 1.54 .mu.m Wavelength". |
Patent Abstracts of Japan, vol. 13, No. 8 (E-702) [3356] Jan. 10, 1989; p. 72 E 702; and JP-A-63 219 186 (Nippon Telegraph & Telephone Corp.). |
Patent Abstracts of Japan, vol. 2, No. 33 (E-19), Mar. 6, 1978, p. 12531 E 77; and JP-A-52 155 901 (Nippon Denshin Denwa Kosha) Dec. 24, 1977. |
Fian Proceedings, Moscow vol. 172, pp. 79, 80, 110. |