Systems and methods are provided for a dual-side bi-directional optical multiplexing system includes a light receiving elements array receiving light from in an egress propagation direction from an optical fiber, arranged at a side of the optical fiber. The system also includes a light transmitting elements array emitting light in an ingress propagation direction into the optical fiber, and arranged at a second position to an opposing side of the optical fiber. The light receiving elements array and the light transmitting elements array are on dual-sides of the system with respect to the optical fiber. The system also includes bi-directional micro-optics interfacing with the optical fiber, and interfacing with the light transmitting elements array to direct light propagating in the ingress direction emitted from the light transmitting element array towards the optical fiber.

Disclosed herein is a wavelength-division multiplexing device with a unified passband. In particular, disclosed is a wavelength-division multiplexing (WDM) device with at least a common port, a channel port, and a WDM filter. The common port is configured for optical communication of a multiplexed signal to the WDM filter. A demultiplexed signal of the multiplexed signal includes a first secondary demultiplexed signal within a first wavelength range and a second secondary demultiplexed signal within a second wavelength range, which are separated from each other by a third wavelength range. The first WDM filter has a single unified passband including the first wavelength range, the second wavelength range, and the third wavelength range, such that the first WDM filter is configured to pass the first secondary demultiplexed signal and the second secondary demultiplexed signal to the first channel port.

Disclosed herein is a wavelength-division multiplexing device with a unified passband. In particular, disclosed is a wavelength-division multiplexing (WDM) device with at least a common port, a channel port, and a WDM filter. The common port is configured for optical communication of a multiplexed signal to the WDM filter. A demultiplexed signal of the multiplexed signal includes a first secondary demultiplexed signal within a first wavelength range and a second secondary demultiplexed signal within a second wavelength range, which are separated from each other by a third wavelength range. The first WDM filter has a single unified passband including the first wavelength range, the second wavelength range, and the third wavelength range, such that the first WDM filter is configured to pass the first secondary demultiplexed signal and the second secondary demultiplexed signal to the first channel port.

An apparatus includes a tail-end optical switch configured to be coupled to a broadcast star network that couples the tail-end optical switch to a head-end optical switch by a primary bidirectional optical path and a second bidirectional optical path. The tail-end optical switch having a first optical switch and a second optical switch configured to provide active switching.

An optical system including a first filter including i) a first port mapped to a first wavelength band and ii) a second port mapped to a second wavelength band, the first filter configured to receive a first transmission signal at the first port and a second transmission signal at the second port, the first transmission signal within the first wavelength band, the second transmission signal within the second wavelength bands; a second filter including i) a third port mapped to the first wavelength band and ii) a fourth port mapped to the second wavelength band, the second filter configured to receive a third transmission signal at the third port and a fourth transmission signal at the fourth port, the third transmission signal within the first wavelength band, the fourth transmission signal within the second wavelength band and; and a wavelength selector

A data center network node (28) comprises one or more switch (18,19,22,23) configured to link an optical transceiver (16,17) to an optical connection comprising a multi-core optical fiber (30) having a plurality of cores (31). For each core (31), the one or more switch (18,19,22,23) is configurable between a first configuration in which an optical signal on a said core (31) of the multi-core optical fiber bypasses the optical transceiver and a second configuration in which the optical transceiver is optically linked to the said core (31) of the multi-core optical fiber (30).

An apparatus includes a reconfigurable optical add/drop multiplexer (ROADM) having an input port to receive a first optical signal from a second device. The ROADM also includes a first wavelength selective switch (WSS), in optical communication with the input port, to convert the first optical signal into a second optical signal, a loopback, in optical communication with the first WSS, to transmit the second optical signal, and a second WSS, in optical communication with the loopback, to convert the second optical signal to a third optical signal and direct the third optical signal back to the second device via the input port.

Systems and methods for performing connectivity verification testing and topology discovery in a reconfigurable optical add/drop multiplexer (ROADM) are provided. The ROADM can include a ROADM block having a plurality of internal ports connected to a fiber shuffle via respective optical fibers. The ROADM block includes a test signal transmitter configured to inject an outgoing test signal having a unique signature into each internal port. The outgoing test signals are out-of-band of optical data signals traversing the ROADM. The ROADM block includes a test signal monitor configured to monitor for incoming test signals at each of the internal ports. The test signal monitor is configured to validate, based on a signature of an incoming test signal received at an internal port of the ROADM block, whether a valid connection exists between the internal port and an internal port of a second ROADM block.

A network node (400) for use with a single-fiber bidirectional communication link comprises a filter (300). The filter (300) comprises at least four ports. A first port (301) is configured to communicate with the single-fiber in a west direction. A second port (303) is configured to communicate with the single-fiber in an east direction. A third port (305) is configured to add/drop in the west direction. A fourth port (307) is configured to add/drop in the east direction. The network node is configured to add a first wavelength (A) to the west direction and the east direction, and configured to drop a second wavelength (B) from the west direction and the east direction.

A transmission quality estimation system includes, three or more nodes and a transmission quality estimation device configured to estimate, transmission quality. A multi-core fiber having a plurality of cores, the multi-core fiber being used in at least a partial segment of a connection between the nodes. A node of the nodes includes a core connection unit configured to drop, add or relay light transmitted from, to or to each of to the plurality of cores of the multi-core fiber. The transmission quality estimation device includes an estimation unit configured to estimate transmission quality between the nodes on the basis of a transmission quality measurement light dropped by the core connection unit.