Optical systems that employ concentric multi core fibers (MCFs) are discussed. Some of the systems discussed are based on the use of a concentric MCF that has a single mode core, capable of carrying a broadband data signal, and a multimode core, which carries optical signals that do not require as high a bandwidth as the broadband data signal. In one embodiment, the multimode core carries system management data. In another embodiment, the multimode core carries a high power optical signal that provides remote power. In another embodiment, the multimode core carries a pump signal for a downstream fiber amplifier. In yet another embodiment, the multimode core carries an optical signal, for example visible light, that can be used to verify connectivity.

A method of interrogating a WDM optical communication system is provided to obtain one or more performance parameters. In accordance with the method, an optical probe wavelength is generated and possibly modulated in a prescribed manner. The probe signal is transmitted along a selected optical path through the WDM optical communication system for a duration of time that is less than a response time of network elements that impact signal quality along the selected optical path.

Systems and methods include causing perturbations across optical spectrum; probing responses across some or all of the optical spectrum after the perturbations; and determining a nonlinear transfer function based on the responses. The nonlinear transfer function can include a representation of any of end-to-end channel powers, Signal-to-Noise Ratio (SNR), Noise-to-Signal Ratio (NSR), Bit Error Rate (BER), Q, and Mean Squared Error (MSE).

A variable optical BPF allows a signal light of a specified wavelength band in a signal light including reference signal lights to pass through. A light receiving unit outputs a level signal indicating a level of the signal light having passed through the variable optical BPF. A control unit refers to a wavelength table held in advance, instructs a wavelength band that passes through the variable optical BPF, and obtains a spectrum of the signal light having passed through the variable optical BPF using the wavelength table and the level signal. The control unit detects a wavelength drift between a center wavelength of the wavelength band instructed to the variable optical BPF to cause the reference signal lights to pass through and center wavelengths of peaks corresponding to the reference signal lights in the spectrum, and updates the wavelength table to corrects the detected wavelength drift.

An extinction ratio testing system (10) includes a microcontroller (102), an extinction ratio tester (104), and a thermostat (106). The microcontroller (102) controls the thermostat (106) to maintain an optical transceiver module (20) at a predetermined high temperature, and then the microcontroller (102) controls the extinction ratio tester (104) to test an extinction ratio of the optical transceiver module (20). If the extinction ratio is lower than a standard extinction ratio, the microcontroller (102) controls the optical transceiver module (20) to increase a laser operating current (212) of the optical transceiver module (20) to increase the extinction ratio.

An optical power value transmission method and system, and a related device is disclosed. The method includes: A source network device obtains optical multiplexing section link information that indicates an optical fiber connection relationship between any two adjacent network devices between the source and a target network device of an optical multiplexing section which are located in different data communication networks. The source network device determines, based on the optical multiplexing section link information, a first output port that connected to a downstream network device by using a first optical fiber, and the downstream network device is connected to the source network device and that is indicated by the optical multiplexing section link information. The source network device obtains, on the first output port, a first output power value of an optical signal and sent it to the downstream network device by using the first optical fiber.

An optical transceiver includes processing circuitry to calculate, when test signals are sent to a transmission line from a transmitter and a receiver receives the test signals having passed through a wavelength filter, a bandwidth of the received test signals, the transmitter generating, as the test signals, a collection of narrowband signals, the narrowband signals having a narrower bandwidth than a bandwidth of the wavelength filter and having different frequencies, and the wavelength filter included in an optical splitter inserted in the transmission line, and the collection of narrowband signals including a narrowband signal having a higher frequency than a highest frequency in the bandwidth of the wavelength filter and a narrowband signal having a lower frequency than a lowest frequency in the bandwidth of the wavelength filter, and to determine a modulation rate and a modulation level of the transmission signal depending on the calculated bandwidth.

An information handling system includes a plurality of network nodes and a processor. Each network node includes an optical link and a reflectometry analyzer. The reflection analyzers provide a plurality of reflectometry results that each provide a characterization of physical properties of the optical link. The processor receives the reflectometry results, analyzes the reflectometry results to define a fingerprint of the physical properties of the optical link, and determines a status for each of the optical links based upon the associated fingerprints. The status for each of the optical links includes one of a plurality of graded statuses. Each graded status represents a qualitative measure of the physical properties of the associated optical link. A first graded status represents a better qualitative measure than a second graded status. The processor further receives a request to route a data flow from a first one of the network nodes to a second one of the network nodes. The data flow is associated with a service level agreement that defines that the data flow is to be routed on optical links that have the first graded status. The processor further determines a path between the first network node and the second network node where each of optical links in the path have the first graded status.

A performance monitor configured to unify at least two different signal-quality estimates into a single performance metric such that a systematic error associated with the performance metric can be approximately constant or smaller than a specified fixed limit over a significantly wider range of data-link conditions than that of a conventional performance metric of similar utility. In an example embodiment, the performance metric can be based on a weighted sum of two different SNR estimates, obtained from an error count of the receiver's FEC decoder and from a constellation scatter plot generated using the receiver's symbol decoder, respectively. Different weights for the weighted sum may be selected for different data-link conditions, e.g., using SNR thresholding, analytical formulas, or pre-computed look-up tables. The performance metric may be supplied to a control entity and considered thereby as a factor in a possible decision to trigger protective switching and/or a transponder-mode change.

This application provides a port detection method and apparatus. In the technical solutions in this application, an OLT or an ONU may determine, based on at least two wavelengths and a preset correspondence, port information that is of an optical splitter and that corresponds to the ONU. That is, a branch port directly or indirectly connected to the ONU is defined by using the at least two wavelengths. In this way, different branch ports can be distinguished by using combinations of a plurality of wavelengths, to define a large quantity of branch ports of the optical splitter by using free combinations of a small quantity of wavelengths.