OPTISCHES NETZWERK

摘要

PCT No. PCT/GB91/02052 Sec. 371 Date Apr. 30, 1993 Sec. 102(e) Date Apr. 30, 1993 PCT Filed Nov. 20, 1991 PCT Pub. No. WO92/09150 PCT Pub. Date May 29, 1992.An optical network includes an erbium-doped silica-based optical fibre having a D-shaped cross-section. The wave-guide carries information signals at 1.53 mu m from a signal source and provides amplification to the information signals when pumped by an optical pump source operating at 0.994 mu m. Optical signals are tapped from the waveguide by means of evanescent couplers. The waveguide provides amplification to at least partially restore tapping loss to the information signal due to the optical taps. The core of the optical waveguide is chosen to substantially minimize the spot size of signals at the wavelength of the pump source so as to provide preferential extraction of the information signal in order to leave the pump source substantially undisturbed to be able to pump regions of the amplifying waveguide beyond the optical tap.