Abstract: “ACTIVE WAVELENGTH CONVERTER FOR USE WITH OTDR, composed of: an optoelectronic circuit 5, comprising a photodetector 6, an amplifier 7, a comparator 8, a laser driver 9, an output laser 10, a laser temperature control circuit 11, and an optical circuit 12, comprising an optical fiber segment 13 with a filtering device 14. The converter 4a is composed of an optoelectronic circuit 5, connected in parallel to the optical circuit 12 by a coupler 15 and a circulator 16. The optical signal emitted by the OTDR 1 through fiber 2a is received by the coupler 15 and sent to the optoelectronic circuit 5, where it is converted from an optical to an electric signal, amplified, saturated, reformatted and converted back to an optical signal again, at a wavelength different from the signal emitted by the OTDR 1. It is then sent to the circulator 16 that transmits this changed signal to the optical fiber 2b, where it is propagated.

Abstract: 1—“ACTIVE WAVELENGTH CONVERTER FOR USE WITH OTDR, composed of: an optoelectronic circuit 5, comprising a photodetector 6, an amplifier 7, a comparator 8, a laser driver 9, an output laser 10, a laser temperature control circuit 11, and an optical circuit 12, comprising an optical fiber segment 13 with a filtering device 14. The converter 4a is composed of an optoelectronic circuit 5, connected in parallel to the optical circuit 12 by a coupler 15 and a circulator 16. The optical signal emitted by the OTDR 1 through fiber 2a is received by the coupler 15 and sent to the optoelectronic circuit 5, where it is converted from an optical to an electric signal, amplified, saturated, reformatted and converted back to an optical signal again, at a wavelength different from the signal emitted by the OTDR 1. It is then sent to the circulator 16 that transmits this changed signal to the optical fiber 2b, where it is propagated.

Abstract: A number of nonlinear optical fibers are configured in a parallel configuration. The fibers are pumped with optical pumps having a wavelength slightly longer than the zero dispersion wavelength for each fiber. By a demultiplexer optical signals within a certain wavelength interval are admitted to enter and exit the different fibers, in which parametric amplification can be achieved. By selecting the pump wavelength outside each corresponding interval crosstalk will be suppressed. The nonlinear fibers can be pumped by separate laser pumps, or two or more of the nonlinear fibers can be pumped by a common pump, depending on the different fiber properties. By tailoring fiber properties such as the zero dispersion wavelength, the second order dispersion coefficient and the fourth order dispersion coefficient, beneficial amplification characteristics can be achieved in different wavelength intervals.