An optical transmitter module includes: a low-speed light emitting device that emits an optical signal at a first given wavelength; a high-speed light emitting device that emits an optical signal at a second given wavelength; and a first filter that transmits one and reflect the other of the first- and second-given-wavelength optical signals to send the optical signal to an optical receiver module. The optical receiver module includes: a low-speed light receiving device that receives the optical signal at the first given wavelength; a high-speed light receiving device that receives the optical signal at the second given wavelength; and a second filter that transmits one and reflects the other of the first- and second-given-wavelength optical signals to send the first-given-wavelength optical signal to the low-speed light receiving device, and the second-given-wavelength optical signal to the high-speed light receiving device.

An optical signal monitor, including: a storage that holds a threshold value set for each of determination areas having a bandwidth set in accordance with an average grid of dummy light; a measurement section that sequentially measures an optical intensity of an inputted wavelength-multiplexed optical signal with respect to each of measurement areas obtained by dividing the determination area into areas with a bandwidth sufficiently smaller than a grid width of a monitoring-target optical signal composing the wavelength-multiplexed optical signal, and output measured values; and a section that determines that dummy light corresponding to the determination area needs introducing if each of measured values in the determination area is smaller than a threshold value, and, determines that dummy light corresponding to the determination area does not need introducing if at least one of the measured values in the determination area is equal to or larger than the threshold value.

A method for determining a maximum transmission capacity, TCAP.sub.MAX-OL, of an optical link, OL, within an optical network includes loading an optical transmission spectrum of the optical link, OL, being partially occupied by at least one data traffic carrying channel, CH, with amplified spontaneous emission, ASE, noise spectrally shaped such that the transmission performance of the optical transmission spectrum fully occupied with data traffic carrying channels, CHs, is matched. The method further includes determining the maximum transmission capacity, TCAP.sub.MAX-OL, of the optical link, OL, on the basis of measured link data transported through the optical link, OL, via the at least one data traffic carrying channel, CH.

An optical signal repeater includes a separation unit that separates the plurality of optical signals according to wavelengths, a first clock data recovery (CDR) circuit configured to extract a first clock included in a first optical signal of the plurality of optical signals and having a first frequency corresponding to a first rate of the plurality of bit rates, a second CDR circuit configured to extract a second clock included in a second optical signal of the plurality of optical signals and having a second frequency corresponding to a second rate of the plurality of bit rates, a synchronous circuit that is synchronized with the first clock when the first clock is generated and is synchronized with the second clock when the first clock is not generated and the second clock is generated, and a control unit that controls the synchronous circuit.

Consistent with the present disclosure, an optical communication system is provided in which data is carried over optical signals including subcarriers. The subcarriers may be modulated with the standard modulation formats noted above, but the modulation formats are selectively assigned to the subcarriers, such that some subcarriers are modulated with different standard modulation formats than others. As used herein, a standard modulation format is one of BPSK, and n-QAM, where n is an integer greater than one. Such n-QAM modulation formats include of 3-QAM, 4-QAM (QPSK), 8-QAM, 16-QAM, 64-QAM, 128-QAM, and 256-QAM. By selecting the number of subcarriers and the types of modulation formats employed, an optical signal with an effective SE that is between that of the standard modulation formats can be generated for transmission over a distances that more closely matches the link distance. Such custom or intermediate SE signals can be tailored to a particular optical link SNR to provide data transmission rates that are higher than the low order modulation formats that would otherwise be employed for optical signals carried by such links. As a result, more efficient data transmission can be achieved.

A computer implemented method of configuring an optical path includes selecting with one or more processors a wavelength for the optical path, generating with one or more processors, a first request for a first type of node in the optical path, generating with one or more processors a second request for a second type of node in the optical path, the second type of node having different data plane capabilities than the first type of node, wherein the first and second requests are generated as a function of a joint configuration model accommodating both types of nodes, and sending the first request from the one or more processors to the first type of node and the second request to the second type of node to configure the optical path.

To enable the transmission and reception of a super-channel optical signal to continue maintaining the possible transmission capacity without providing a redundant configuration in advance even though a failure occurs in a subcarrier, an optical transmitter 10 of the present invention includes a splitting means 20 for splitting an inputted client signal so as to make frequency efficiency in optical modulation means optimized; optical modulation means 31 to 3N for modulating one of subcarriers having mutually different wavelengths with the client signal output; a multiplexing means 40 for multiplexing the modulated signals and outputting a super-channel optical signal; and a control means 50, in a state where a failure occurs in one of the subcarriers, for making a split client signal output to modulation means corresponding to a subcarrier having no failure and applying a modulation method with a higher frequency efficiency to at least one of the modulation means.

An optical signal monitor, including: a storage that holds a threshold value set for each of determination areas having a bandwidth set in accordance with an average grid of dummy light; a measurement section that sequentially measures an optical intensity of an inputted wavelength-multiplexed optical signal with respect to each of measurement areas obtained by dividing the determination area into areas with a bandwidth sufficiently smaller than a grid width of a monitoring-target optical signal composing the wavelength-multiplexed optical signal, and output measured values; and a section that determines that dummy light corresponding to the determination area needs introducing if each of measured values in the determination area is smaller than a threshold value, and, determines that dummy light corresponding to the determination area does not need introducing if at least one of the measured values in the determination area is equal to or larger than the threshold value.

A method for determining a maximum transmission capacity, TCAP.sub.MAX-OL, of an optical link, OL, within an optical network includes loading an optical transmission spectrum of the optical link, OL, being partially occupied by at least one data traffic carrying channel, CH, with amplified spontaneous emission, ASE, noise spectrally shaped such that the transmission performance of the optical transmission spectrum fully occupied with data traffic carrying channels, CHs, is matched. The method further includes determining the maximum transmission capacity, TCAP.sub.MAX-OL, of the optical link, OL, on the basis of measured link data transported through the optical link, OL, via the at least one data traffic carrying channel, CH.

A method and system for transmitting information in well operations. The method for transmitting information may comprise splitting a coherent light into a plurality of wavelengths with a demultiplexer within a fiber comb transmitter and encoding information onto at least one of the plurality of wavelengths within the fiber comb transmitted. The method may further comprise combining the plurality of wavelengths into a second coherent light with a wavelength division multiplexer within the fiber comb transmitter and broadcasting the second coherent light from the frequency comb transmitter. A downhole telemetry system may comprise a frequency comb transmitter, which may comprise a laser source and a modulator. The modulator may further comprise a demultiplexer, an encoder, and a wavelength division multiplexer. The frequency comb transmitter may also comprise a fiber optic cable and a frequency comb receiver.