Abstract: In an optical amplifying technique using remote pumping, an optical transmitting apparatus and an optical repeating apparatus are provided. An optical repeating apparatus comprises a first optical transmitting unit, a first loopback unit, a second optical transmitting unit, a second loopback unit, and four optical couplers, wherein transmission light and reception light are transmitted through one optical fiber cable, whereby the installation cost and maintenance cost of the optical cable are decreased. Disconnect of the optical cable is detected by a monitoring function using pumping light and residual pumping light, whereby reliability and safety of the system are remarkably improved. Additionally, adjustment of the optical output level of the repeating station can be most suitably set according to an actual transmission distance.

Abstract: In an optical amplifying technique using remote pumping, an optical transmitting apparatus and an optical repeating apparatus are provided. An optical repeating apparatus comprises a first optical transmitting unit, a first loopback unit, a second optical transmitting unit, a second loopback unit, and four optical couplers, wherein transmission light and reception light are transmitted through one optical fiber cable, whereby the installation cost and maintenance cost of the optical cable are decreased. Disconnect of the optical cable is detected by a monitoring function using pumping light and residual pumping light, whereby reliability and safety of the system are remarkably improved. Additionally, adjustment of the optical output level of the repeating station can be most suitably set according to an actual transmission distance.

Abstract: In an optical amplifying technique using remote pumping, an optical transmitting apparatus and an optical repeating apparatus are provided. An optical repeating apparatus comprises a first optical transmitting unit, a first loopback unit, a second optical transmitting unit, a second loopback unit, and four optical couplers, wherein transmission light and reception light are transmitted through one optical fiber cable, whereby the installation cost and maintenance cost of the optical cable are decreased. Disconnect of the optical cable is detected by a monitoring function using pumping light and residual pumping light, whereby reliability and safety of the system are remarkably improved. Additionally, adjustment of the optical output level of the repeating station can be most suitably set according to an actual transmission distance.

Abstract: The present invention relates to a wavelength division multiplex optical transmission apparatus including an optical sending system having at least a plurality of optical sending sections to generate and transmit optical signals having different wavelengths [hereinafter referred to as optical signals] , a plurality of optical amplifying sections to amplify the optical signals, and a wavelength division multiplexing section to process by wavelength division multiplexing the optical signals after optical amplification. An optical output level control section is mounted in the apparatus to control, for the wavelengths, optical output levels of the optical signals output to the optical transmission line through the wavelength division multiplexing section by individually varying amplification factors of the optical amplifying sections in the optical sending system.

Abstract: A first transmitting unit provided in a first station transmits a first optical signal to a second receiving unit provided in a second station via an optical transmission line, the first optical signal including first overhead information. A first receiving unit provided in the first station receives a second optical signal transmitted from a second transmitting unit provided in the second station via the optical transmission line, the second optical signal including second overhead information. A first inserting unit inserts first data for detecting line-disconnection troubles into the first overhead information, the data inserting being performed without causing a data amount of the first overhead information to be increased, contents of the first data for detecting line-disconnection troubles being different from contents of second data for detecting line-disconnection troubles being inserted into the second overhead information by a second inserting unit provided in the second station.

Abstract: A transmission device includes an exciting light source outputting an exciting light, a first optical part which supplies an optical amplifying part with a signal light and the exciting light, a second optical part which supplies an amplified light to an optical transmission line and receives a light received via the optical transmission line, and a control part which determines whether the light received includes the exciting light output by the exciting light source and controls the exciting light source to stop outputting the exciting light.

Abstract: An optical line switch device which contains: an optical switch which can input a transmission optical signal which is to be transmitted through one of first and second optical transmission lines, first and second optical coupling and branching units which can be connected with the first and second optical transmission lines, respectively, and an optical coupling unit which can output an input optical signal which is input from one of the first and second optical transmission lines. The transmission optical signal is supplied to one of the first and second optical coupling and branching units according to a switch control signal which is applied to the optical switch when the optical switch inputs the transmission optical signal. One of the first and second optical coupling and branching units transmits the transmission optical signal on one of the first and second optical transmission lines connected thereto when the transmission optical signal is supplied thereto.