Aspects of the present disclosure describe systems, methods, and structures for passive optical add/drop multiplexing (POADM) architectures that remove the prior art requirement of an optical amplifier (i.e., repeater-less) at the POADM nodes.

There is provided an optical signal monitoring device and an optical signal monitoring system of a wavelength division multiplexing based network including: an input unit configured to receive each of downlink signals and uplink signals; a wavelength division multiplexing filter configured to separate the downlink signals and the uplink signals by wavelength; an optical power measurement module configured to measure optical power of each signal separated by wavelength; and a controller configured to determine whether an optical signal is abnormal based on optical power information measured by the optical power measurement module.

Example embodiments of the present invention relate to programmable ROADMs used to construct optical nodes. Example embodiments include wavelength switches and waveguide switches, wherein the waveguide switches may be programmed to direct wavelength division multiplexed optical signals to and from the wavelength switches.

A satellite system may have a constellation of communications satellites that provides services to users with electronic devices such as portable electronic devices and home/office equipment. The satellites may support communications between the electronic devices of the users and gateways. Each gateway may have satellite transceiver circuitry that transmits and receives satellite signals. Each gateway may also have an optical add-drop multiplexer coupled to a fiber ring and radio-frequency-over-fiber circuitry coupled between the satellite transceiver circuitry and the optical add-drop multiplexer. A metropolitan point-of-presence may be in communication with the fiber ring and may have modems for centrally processing communications (received and transmitted in an intermediate frequency) in the satellite system.

In order to provide a power supply path-switching device, a power supply path-switching system, and a power supply path-switching method with which it is possible to utilize to the maximum equipment in which a failure has not occurred without imparting a power supply function to a branch station side even when a failure has occurred in the power supply function of the trunk station side, a power supply path-switching device (10) is provided with a first switching means (20), a second switching means (30), a grounding means (40), and a power consumption circuit (50) that operates by being supplied with the power supply. When a failure occurs in a first power supply line (61), the power consumption circuit (50) grounds the first power supply line (61), one end of the power consumption circuit (50) being connected to the grounding means (40) and a second power supply line (62) being connected to the other end of the power consumption circuit (50). When a failure occurs in the second power supply line (62), the power consumption circuit (50) grounds the second power supply line (62), the first power supply line (61) being connected to one end of the power consumption circuit (50) and the other end of the power consumption circuit (50) being connected to a grounding means (24).

Disclosed herein are methods, devices, and systems for providing timing and bandwidth management of ultra-wideband, wireless data channels (including radio frequency and wireless optical data channels). According to one embodiment, a hub apparatus is disclosed for providing out-of-band bandwidth management for a free-space-optical (FSO) data channel associated with a first device. The hub apparatus includes a processor, a memory coupled with the processor, an FSO transmitter coupled with the processor, and an FSO receiver coupled with the processor. The FSO transmitter may be configured to transmit a control signal comprising timing information and bandwidth management information.

A process of assembling an optical receiver module that receives a wavelength multiplexed signal is disclosed. The process includes a step of sequentially mounting a wavelength selective filter (WSF), a prism, a mirror, and first and second optical de-multiplexers (o-DeMuxes) each on the carrier. The WSF transmits a first wavelength multiplexed signal but reflects a second wavelength multiplexed signal. The prism includes first and second surfaces, where the first surface reflects the wavelength multiplexed signal toward the WSF, while the second surface receives a second wavelength multiplexed signal coming from the WSF. The mirror reflects the first wavelength multiplexed signal transmitting through the WSF. The first and second o-DeMuxes de-multiplex the first and second wavelength multiplexed signals.

In part, the disclosure relates to system. The system includes a polarization diversified wavelength demultiplexer (WDM). The polarization diversified wavelength demultiplexer includes a polarization beam splitter configured to output a first polarized signal and a second polarized signal based on an input signal; and a wavelength demultiplexer (WDM) having two inputs that are connected to the two outputs of the polarization beam splitter, and configured to output signals with a single set of outputs that carry signals of both polarizations, based on the first polarized signal from the first input and the second polarized signal from the second input.

Example embodiments of the present invention relate to programmable ROADMs used to construct optical nodes. Example embodiments include wavelength switches and waveguide switches, wherein the waveguide switches may be programmed to direct wavelength division multiplexed optical signals to and from the wavelength switches.

Disclosed is a multi-wavelength transmission apparatus including a wavelength divider to divide an optical signal by wavelength and output wavelength-divided optical signals to different positions, the optical signal being received from an optical circulator, a first cylindrical lens to diverge the wavelength-divided optical signals along an X axis and a Y axis and allow the wavelength-divided optical signals to be promoted in a Z-direction, a second cylindrical lens to diverge optical signals output from the first cylindrical lens along the X axis and the Y axis and allow the output optical signals to be promoted in the Z-direction, and a reflector to reflect optical signals output from the second cylindrical lens toward the second cylindrical lens, the first cylindrical lens being identical in shape to the second cylindrical lens and rotated by 90 in an Y-axial direction based on the second cylindrical lens.