An optical switch, comprising: a first optical waveguide, a first optical add path, a second optical add path and a micro-ring resonator. The micro-ring resonator is operable to add a first optical signal at a preselected wavelength received from the first optical add path to the first optical waveguide to travel in a first direction through the first optical waveguide. The micro-ring resonator is further operable to add a second optical signal at the preselected wavelength received from the second optical add path to the first optical waveguide to travel in a second direction through the first optical waveguide opposite to the first direction. There is also provided an optical drop switch, an optical switching apparatus, an optical communications network node and an optical communications network.

10-Gbps client signals (1a) to (1c) which are processed by a 10-Gbps transponder (3a), a 40-Gbps transponder (3b), and a 100-Gbps transponder (3c), respectively, are branched by optical couplers (2a) to (2c) into an M:N switch (40). The M:N switch (40) selects a client signal to be made redundant from the branched client signals (1a) to (1c) and outputs the selected client signal to a redundancy 100-Gbps transponder (50) having 10-Gbps-based client interfaces.

An optical network is configured to optimize network resources. The optical network includes multiple optical nodes, light paths between the multiple optical nodes, and a network monitoring device. The network monitoring device monitors the optical network to identify a failure in the optical network. When the failure is a fiber failure, light paths are re-routed around the fiber failure while maintaining the required bandwidth for the optical network. When the failure is a transponder card failure within one of the multiple nodes, a floating spare card may be provisioned to service a particular light path associated with the transponder card failure. When the failure is a node failure, transponder cards in some of the multiple optical nodes are provisioned to reconfigure some of the plurality of light paths to route traffic around the failed node.

The disclosed technology allows for 1+1 optical protection and may improve coherent module output optical power by 3 dB over similar transmitter (Tx) and receiver (Rx) implementation complexity, as well as allow for integration into existing datacenter formats.

An optical switch, comprising: a first optical waveguide, a first optical add path, a second optical add path and a micro-ring resonator. The micro-ring resonator is operable to add a first optical signal at a preselected wavelength received from the first optical add path to the first optical waveguide to travel in a first direction through the first optical waveguide. The micro-ring resonator is further operable to add a second optical signal at the preselected wavelength received from the second optical add path to the first optical waveguide to travel in a second direction through the first optical waveguide opposite to the first direction. There is also provided an optical drop switch, an optical switching apparatus, an optical communications network node and an optical communications network.

A network management device monitors an optical network that is configured for a required bandwidth. The optical network includes multiple optical nodes and a plurality of light paths between the multiple optical nodes. The multiple optical nodes include transport cards with a majority of the transport cards provisioned as active cards to receive a traffic load of up to full capacity of the transport cards, and with a minority of the transport cards provisioned as floating spare cards for the active cards. The network management device identifies an unused first floating spare card and an unused second floating spare card in a pair of the multiple optical nodes and automatically provisions, by the network management device, the first floating spare card and the second floating spare card to service a light path for best-effort traffic between the pair of the multiple optical nodes.

A communications network remote node having a downstream optical circuit configured to receive downstream, DS, optical signals from an active main node and from a standby main node, the downstream optical circuit switchable between a working mode and a protection mode. Optical receivers are configured to receive the demultiplexed downstream optical signals and output encapsulated downstream client signals. Optical transmitters are configured to receive encapsulated upstream client signals and to transmit upstream, US, optical signals at upstream wavelengths carrying the encapsulated upstream client signals. An upstream optical circuit is configured to multiplex the upstream optical signals carrying the encapsulated upstream client signals and to send the upstream optical signals to both main nodes. Processing circuitry is configured to extract downstream client signals and alignment data from encapsulated downstream client signals and form encapsulated upstream client signals by encapsulating upstream client signals and alignment data.