One embodiment provides a system for measuring optical fiber channel loss in photonic communication. During operation, a first multiplexing device receives a first signal which is a photonic signal and a second signal which is a reference light signal transmitted by a first measuring device. In response, the first multiplexing device couples the first signal with the second signal, and transmits the coupled signal via an optical fiber channel to a second multiplexing device. The second multiplexing device separates the coupled signal into a separated first signal and a separated second signal, and transmits the separated second signal to a second measuring device. The system obtains indices related to a degree of loss of the optical fiber channel based on the separated second signal.

A transmission and reception apparatus, includes a processor and a processing device coupled to the processor, wherein the processor is configured to detect insertion of a pluggable module, issue, when the insertion of the pluggable module is detected, an instruction to the processing device to generate a first test signal to be supplied to the pluggable module, extract an alternating current component from a first monitoring result of the first test signal by the pluggable module and acquiring pulse width information at a plurality of phase points, and set a phase point determined based on the pulse width information as an optimum phase value to the processing device.

A light monitoring mechanism for monitoring light in an optical circuit (10) including a loopback mirror (12) in loopback shape to which a linear optical waveguide (11) is connected has a structure in which a tap port (15) in loopback or loop shape is placed in close proximity to a position on the loopback mirror (12) where optical lengths from a connection point between the loopback mirror (12) and the optical waveguide (11) when light travels clockwise and when light travels counterclockwise are equal, which enables extraction a part of light from the loopback mirror (12) to the tap port (15) as monitoring light without optical loss. A light monitoring mechanism having a structure that minimizes the occurrence of optical loss when extracting light for monitoring is thereby provided.

According to examples, a wavelength identification and analysis sensor may include a wavelength transmitter, operably connectable to an input or output of a wavelength selective device of a wavelength division multiplex (WDM) network, to transmit test signals on a plurality of wavelengths into the input or output of the wavelength selective device of the WDM network. A wavelength analyzer is to detect returned signals from the input or output of the wavelength selective device of the WDM network, with each returned signal being associated with one of the transmitted test signals. Further, the wavelength analyzer is to analyze the returned signals and identify, based on the analysis of the returned signals, a wavelength associated with the input or output of the wavelength selective device of the WDM network.

A method and an apparatus for monitoring a wavelength channel are disclosed. The method includes: performing optical-to-electrical detection on an optical signal on a wavelength channel, to obtain an electrical signal; obtaining a frequency spectrum of the electrical signal; determining a first parameter M according to an equation M=N.sub.AC, where N.sub.AC represents an alternating current component of the frequency spectrum of the electrical signal; and if M is greater than a preset first threshold, determining that the wavelength channel includes a real service signal. According to the method and apparatus, an erroneous configuration or operation of a network management system can be avoided.

In the examples provided herein, a system includes an input waveguide, where a first end of the input waveguide is coupled to a light-emitting optical transmitter to allow the emitted light to enter the input waveguide, and a first ring resonator tunable to be resonant at a first resonant wavelength, wherein the first ring resonator is positioned near the input waveguide to couple a light at the first resonant wavelength from the input waveguide to the first ring resonator. The system also has a bus waveguide positioned to couple the light at the first resonant wavelength in the first ring resonator to the bus waveguide, and a mechanism to wavelength-tune the first ring resonator to a particular wavelength.

An optical transmission device includes an optical amplifier that optically amplifies a wavelength multiplexing signal which is input, a wavelength selective switch that splits, inserts, or transmits an optical signal of any wavelength of the wavelength multiplexing signal, an optical channel power monitor that detects power of each channel of the wavelength multiplexing signal which is input and the wavelength multiplexing signal which is output, and a controller that calculates an amount of change in the optical signal of each channel in which a gain of each channel between an input and an output to and from the device is steady, and adjusts an amount of attenuation of the wavelength selective switch, based on the power of each channel of the wavelength multiplexing signal that is detected by the optical channel power monitor.

Proposed is a method of receiving a WDM optical upstream signal in an optical access network. The WDM signal is filtered using a first optical filter yielding a first filtered signal. The first optical filter has a flat-top shaped pass-band transfer function. Furthermore the WDM signal is filtered using second optical filter yielding a second filtered signal. The second optical filter has a pass-band transfer function that is strictly monotonically increasing for wavelength values below a center wavelength of the transfer function and that is strictly monotonically decreasing for wavelength values above the center wavelength of the transfer function. Received upstream data is derived from the first filtered signal. An optical signal power level is derived from the second filtered signal an optical signal power level. Finally, it is indicated to an optical network unit a desired direction of wavelength shift in dependence on the derives signal power level.

A device may provide a signal with a first wavelength and a second wavelength to a fiber cable, and may receive an intensity change measurement of backscattered light based on the first wavelength of the signal. The device may receive a differential phase change measurement of the backscattered light based on the second wavelength of the signal, and may determine whether there is a fiber loss change, a fiber length change, and/or a fiber cut associated with the fiber cable based on the intensity change measurement. The device may determine whether there is an abnormal event associated with the fiber cable based on the differential phase change measurement, and may report one or more of the fiber loss change, the fiber length change, the fiber cut, or the abnormal event.

A device may provide a signal with a first wavelength and a second wavelength to a fiber cable, and may receive an intensity change measurement of backscattered light based on the first wavelength of the signal. The device may receive a differential phase change measurement of the backscattered light based on the second wavelength of the signal, and may determine whether there is a fiber loss change, a fiber length change, and/or a fiber cut associated with the fiber cable based on the intensity change measurement. The device may determine whether there is an abnormal event associated with the fiber cable based on the differential phase change measurement, and may report one or more of the fiber loss change, the fiber length change, the fiber cut, or the abnormal event.