Abstract: A wavelength division multiplexing passive optical network system is provided. A central office generates a multi-mode light having a mode interval equal to a period interval of a multiplexing filter of the remote node and the multi-mode light is used to control a wavelength of an uplink transmission optical signal of the optical network unit. A remote node multiplexes the multi-mode light with the multiplexing filter to transmit the multiplexed multi-mode light to the optical network unit and demultiplexes the uplink transmission optical signal to transmit the demultiplexed uplink transmission optical signal to the central office. An the optical network unit generates the uplink transmission optical signal by modulating a data signal with a Fabry-Perot laser which uses the multiplexed multi-mode light as an injection optical source. Accordingly, it is possible to control a wavelength of a transmitter of the optical network unit by using the injection optical source generated by the central office.

Abstract: In an optical amplifier and a method thereof, and in particular to a wavelength division multiplexing system using a C-band optical signal and a L-band optical signal, by using a portion of a C-band optical signal filtered out during gain flattening as a pump optical signal for amplification of an L-band optical signal, optical components required by prior systems for providing a pump optical signal to an L-band optical signal amplifier are not required. Accordingly, the present invention reduces the number of required optical components. In addition, by using the portion of the C-band optical signal filtered out during gain flattening, energy usage efficiency is improved.

Abstract: In an optical amplifier and a method thereof, and in particular to a wavelength division multiplexing system using a C-band optical signal and a L-band optical signal, by using a portion of a C-band optical signal filtered out during gain flattening as a pump optical signal for amplification of an L-band optical signal, optical components required by prior systems for providing a pump optical signal to an L-band optical signal amplifier are not required. Accordingly, the present invention reduces the number of required optical components. In addition, by using the portion of the C-band optical signal filtered out during gain flattening, energy usage efficiency is improved.