In various aspects, an optical connector with a built-in photodetector for detecting light in the optical connector; an adapter for detachably receiving an optical connector, comprising an electrode configured to electrically contact an electrode of the optical connector; a connection apparatus comprising an arrangement of adapters for detachably receiving a plurality of optical connectors, each adapter comprising an electrode configured to electrically contact an electrode of the respective optical connector; a system with an interface configured to make an optical connection with an optical connector and a processing unit configured to receive from the connector an indication and to generate a feedback signal indicative of said indication; and/or an optical connector responsive to light to generate an electrical signal is provided.

In various aspects, an optical connector with a built-in photodetector for detecting light in the optical connector; an adapter for detachably receiving an optical connector, comprising an electrode configured to electrically contact an electrode of the optical connector; a connection apparatus comprising an arrangement of adapters for detachably receiving a plurality of optical connectors, each adapter comprising an electrode configured to electrically contact an electrode of the respective optical connector; a system with an interface configured to make an optical connection with an optical connector and a processing unit configured to receive from the connector an indication and to generate a feedback signal indicative of said indication; and/or an optical connector responsive to light to generate an electrical signal is provided.

A signal detection device including: a comparison unit that obtains data including central frequencies of optical signals respectively transmitted by a plurality of optical transmitters and a central frequency interval indicating the interval between the central frequencies, power measurement values obtained by measuring, at sampling point frequencies arranged at a prescribed sampling interval, the power of a WDM signal for which the wavelength of optical signals has been multiplexed, a sampling interval, and sampling point frequencies, that selects a selection value from among the power measurement values on the basis of the central frequency interval and the sampling interval, and that outputs a result of comparison between the selection value and a prescribed threshold; and an alarm generator that outputs a signal interruption alarm in a case where the comparison result indicates that the selection value is less than the threshold.

An optical multiplexing device includes: a control light generator that generates control lights each being a continuous wave light and a subcarrier signal based on an insertion signal having respective optical frequencies, polarized states of the control lights being perpendicular to each other; and at least one nonlinear optical medium that modulates a carrier light based on the control lights.

An optical multiplexing device includes: a control light generator that generates control lights each being a continuous wave light and a subcarrier signal based on an insertion signal having respective optical frequencies, polarized states of the control lights being perpendicular to each other; and at least one nonlinear optical medium that modulates a carrier light based on the control lights.

A procedure for transferring wavelengths, and a system that operates in accordance with the procedure. The system comprises at least one network terminal, each including a switch and a controller. A plurality of wavelength sets are applied to the switch. The controller is arranged to operate the switch such that the switch (a) selects at least one wavelength from at least one of the plurality of wavelength sets, based on electrical monitoring at a port module external to the network terminal, and (b) outputs the at least one wavelength to an output of the at least one network terminal.

A procedure for transferring wavelengths, and a system that operates in accordance with the procedure. The system comprises at least one network terminal, each including a switch and a controller. A plurality of wavelength sets are applied to the switch. The controller is arranged to operate the switch such that the switch (a) selects at least one wavelength from at least one of the plurality of wavelength sets, based on electrical monitoring at a port module external to the network terminal, and (b) outputs the at least one wavelength to an output of the at least one network terminal.

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.

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.

Systems and methods for characterizing an optical fiber performed in part by an optical node (12) in an optical line system (10) include performing one or more measurements to characterize the optical fiber (16, 18) with one or more components (50, 52) at the optical node (12), wherein the one or more components (50, 52) perform functions during operation of the optical node (12) and are reconfigured to perform the one or measurements independent of the functions; and configuring the optical node (12) for communication over the optical fiber (16, 18) based on the one or more measurements. The one or more components can include any of an Optical Service Channel (OSC), an Optical Time Domain Reflectometer (OTDR), and an optical amplifier. The configuring can include setting a launch power into the optical fiber based on the one or more measurements.