Safety power disconnection for remote power distribution in power distribution systems is disclosed. The power distribution system includes one or more power distribution circuits each configured to remotely distribute power from a power source over current carrying power conductors to remote units to provide power for remote unit operations. A remote unit is configured to decouple power from the power conductors thereby disconnecting the load of the remote unit from the power distribution system. A current measurement circuit in the power distribution system measures current flowing on the power conductors and provides a current measurement to the controller circuit. The controller circuit is configured to disconnect the power source from the power conductors for safety reasons in response to detecting a current from the power source in excess of a threshold current level indicating a load.

An optical terminal device includes: a relay processing circuitry relaying communication between first base stations, respectively connected to optical terminating devices at branch destinations of a transmission path, and a control device controlling the first base stations in accordance with information acquired from a second base station covering a cell overlapping cells of the first base stations; a detecting circuitry detecting a sleep control instruction, issued for one of the first base stations from the control device, from the communication being relayed by the relay processing circuitry; and a control circuitry performing control, via the transmission path, to cause the optical terminating device connected to the one of the first base stations to shift to an operating state or a sleep state, which consumes less power than the operating state, in response to detection of the sleep control instruction, the optical terminating device being one of the optical terminating devices.

Devices and methods are provided to reduce the wake-up time of a Vertical Cavity Surface Emitting Laser (VCSEL) used in a data communication link. For example, in one aspect, a method for optical communications includes, in an optical communication device including a light-emitting device, applying a bias current to the light-emitting device and transmitting a pulse to the light-emitting device before transmitting a preamble signal or data signal to the light-emitting device, wherein the pulse has a voltage greater than a highest voltage of the preamble signal or data signal.

The disclosed methods, apparatus, and systems allow safe and easy deployment of amplifier products that exceed laser safe limits without the need for fiber testing and characterization or OTDR techniques. One example embodiment is a method for ensuring eye safety in an optical network. The example method includes detecting optical connectivity between an output of a transmit amplifier and a passive optical processing element. The transmit amplifier is located at a first network node and is configured to output optical power greater than eye-safe level. The passive optical processing element is located at a second network node and is configured to guarantee a reduction of a maximum optical power level at an output side of the passive optical processing element to an eye-safe optical level. The detecting occurs at the first network node, and the transmit amplifier is enabled or disabled as a function of detection of the optical connectivity.

A communication node for optical-wireless communication in an optical-wireless communication network has: an input interface configured to receive a data signal, an optical transmitter configured to convert the data signal into an optical signal having an optical power, separation optics configured to spatially divide the optical signal into a plurality of optical partial signals having an associated spectral range to divide the optical power onto the plurality of optical partial signals, wherein the plurality of spectral ranges at least partially match. The communication node is configured to emit the plurality of optical partial signals for optical-wireless communication.

A communication device includes a transmitter configured to generate a data signal, and a controller configured to stop an operation of the transmitter in response to an optical transmission stop instruction. The optical transmission stop instruction preferably has a predetermined bit pattern.

An optical link power management scheme takes the best advantage of a dynamic connection environment, where ports may be connected and disconnected at any time, and where data flows may start and stop as needed by the applications using the high speed data links. Power consumption is optimized, eye safety standards are met, and robust connection detection is preserved.

A communication light visualization module includes multiple communication light visualization adapters into which an optical connector is fitted and to which the optical connector is optically connected and a housing that houses the communication light visualization adapters in an arrangement manner. Each of the communication light visualization adapters includes a light extraction hole from which part of communication light transmitted through an optical communication path is extracted. The housing includes a common protection cover that collectively covers the light extraction holes of the plurality of communication light visualization adapters or collectively renders the light extraction holes uncovered.

An optoelectronic transceiver includes an optoelectronic transmitter, an optoelectronic receiver, memory, and an interface. The memory is configured to store digital values representative of operating conditions of the optoelectronic transceiver. The interface is configured to receive from a host a request for data associated with a particular memory address, and respond to the host with a specific digital value of the digital values. The specific digital value is associated with the particular memory address received from the host. The optoelectronic transceiver may further include comparison logic configured to compare the digital values with limit values to generate flag values, wherein the flag values are stored as digital values in the memory.

When an unsafe port with a loss of signal is detected, a transceiver may enable one laser in a group of lasers associated with the unsafe port and may disable the remaining lasers. Then, the transceiver may instruct a transmitter associated with the one laser to transmit an optical signal on the unsafe port using a reduced transmit power that is less than a threshold value associated with the Class 1 conditions and at a different time than enabled lasers in other groups of lasers. Alternatively, for a safe port on which valid communication is received, the transceiver may enable lasers in a group of lasers associated with the safe port. Then, the transceiver may instruct transmitters associated with the lasers in this group of lasers to transmit optical signals on the safe port using a normal transmit power for the lasers that is greater than the threshold value.