An embodiment method includes multiplexing light emitted by the plurality of optical transmitters to provide a multiplexed optical signal; propagating the multiplexed optical signal through an optical interleaver from a first port thereof to a combined port thereof and back to a second port thereof; and detecting an optical signal at the second port of the optical interleaver.

A wavelength tuning method and a related device, the method including receiving, by a remote optical module, a wavelength control signal from a central office terminal, where the wavelength control signal indicates a target wavelength tuned by the remote optical module, and where the wavelength control signal is loaded into a first optical service signal in a pilot tone manner, and tuning, by the remote optical module, an operating wavelength of the remote optical module based on the wavelength control signal.

An optical transmission system includes a transmitting node that transmits wavelength light of an operational path to an optical waveguide, and a receiving node that receives the wavelength light from the optical waveguide. The transmitting node includes a light source that generates spontaneously emitted light and a wavelength selector that generates and outputs dummy wavelength light from the spontaneously emitted light generated by the light source. The receiving node includes an extractor that extracts spectral data of the dummy wavelength light passed in the optical waveguide. The optical transmission system further includes an obtainer that obtains a band state of the operational path from the spectral data of the dummy wavelength light extracted by the extractor.

A method for establishing an embedded optical communication channel in an optical WDM transmission system including: creating, at the central network device, a broad-band optical signal, supplying the broadband optical signal, transmitting the broadband optical signal and the plurality of second optical channel signals to an optical demultiplexer device, transmitting an optical signal consisting of a dedicated second optical channel signal and a filtered broadband optical signal; receiving the optical signal and creating a corresponding electrical receive signal and extracting the electrical signal corresponding to the filtered broadband optical signal from the electrical receive signal and detecting whether the electrical signal contains information intended for the respective first channel transceiver.

Embodiments can provide spurs removal in a pilot-tone spread signal. For achieving this, at least one peak in the pilot-tone spread signal may be found. A predetermined small range of the spectra power around the at least one peak may be removed. In some situations, the removal of the spurs in the pilot-tone spread signal may result in inadvertent removal of a normal part of the pilot-tone spread signal. For addressing this, a power ratio between the spectrum of the pilot-tone spread signal before the removal and after the removal can be calculated. For accounting for the power loss due to the spurs removal, this power ratio can be applied to the pilot-tone spread signal after the removal to obtain a corrected pilot-tone spread signal.

An optical transmission apparatus includes a wavelength variable filter whose transmission light wavelength is variable; a receiver that receives light, the light being sent from another optical transmission apparatus and passing through the wavelength variable filter; a transmitter that sends to the another optical transmission apparatus, a utilization permission request for a second wavelength corresponding to a first wavelength of the light received by the receiver, the transmitter sending the utilization permission request as light of the second wavelength and in a form of a tone signal of a predetermined frequency; and a controller that, when receiving from the another optical transmission apparatus, a utilization permission notification of the second wavelength for a sender of the utilization permission request, configures a wavelength of a main signal to the second wavelength, the main signal being sent from the transmitter to the another optical transmission apparatus.

The disclosure is directed to a method and system for generating a pilot tone for an optical signal with an optical telecommunications system. The pilot tone is generated in the digital domain by modulating the data to be transmitted to a destination node within the optical telecommunications network. The modulation of the data introduces occurrence modulation to the optical signal.

An optical modulator combines and inputs a signal light propagating through the optical network and a control light having information concerning the optical network to a nonlinear optical medium. The optical modulator modulates the signal light according to changes in intensity of the control light, in the nonlinear optical medium.

An embodiment method includes multiplexing light emitted by the plurality of optical transmitters to provide a multiplexed optical signal; propagating the multiplexed optical signal through an optical interleaver from a first port thereof to a combined port thereof and back to a second port thereof; and detecting an optical signal at the second port of the optical interleaver.

Embodiments can provide spurs removal in a pilot-tone spread signal. For achieving this, at least one peak in the pilot-tone spread signal may be found. A predetermined small range of the spectra power around the at least one peak may be removed. In some situations, the removal of the spurs in the pilot-tone spread signal may result in inadvertent removal of a normal part of the pilot-tone spread signal. For addressing this, a power ratio between the spectrum of the pilot-tone spread signal before the removal and after the removal can be calculated. For accounting for the power loss due to the spurs removal, this power ratio can be applied to the pilot-tone spread signal after the removal to obtain a corrected pilot-tone spread signal.