The noise decrease device of the signal light which features that in order

摘要

PROBLEM TO BE SOLVED: To contrive to prolong the span of a transmission distance by reducing amplified spontaneous emission (ASE) undesirably generated in optical communication.;SOLUTION: The noise reduction device uses a carbon nanotube as a saturable absorber 15. The saturable absorber ensures the functioning of blocking or reducing the transmission of the undesirable amplified spontaneous emission (ASE) or the like having low signal light intensity and of transmitting signal light having high optical intensity. The noise reduction device is inserted in a passage for the signal light in a bi-directional excitation type EDFA (erbium doped fiber amplifier) 50, for example, more particularly, the noise reduction device is inserted in the downstream part of the EDF 40 to contrive its use in the optical communication field of the carbon nanotube having a saturable absorption function.;COPYRIGHT: (C)2003,JPO