An optical module is disclosed. The optical module includes a first downlink port, a second downlink port, a directional coupler, a optical attenuator, a first photodiode (PD), and a second PD. The directional coupler, connected to the first downlink port, is configured to receive a downlink optical signal. The second PD connected to the directional coupler, is configured to obtain a power value. If the power value is greater than a first threshold, the optical attenuator is configured to receive a attenuation control signal, and attenuate, based on the attenuation control signal, a power of an optical signal passing through the second downlink port. The first PD is configured to: convert the downlink optical signal into a downlink electrical signal, and convert the optical signal passing through the second downlink port into an electrical signal. Both the first downlink port and the second downlink port are connected to the first PD.

Embodiments of this application disclose an optical switch. The optical switch includes at least one first port, at least one second port, a first wavelength division multiplexing WDM apparatus, an optical splitter, an optical monitoring apparatus, and an optical switching apparatus. The first port is configured to transmit an input first optical signal to the first WDM apparatus, where the first optical signal is a multi-wavelength signal. The first WDM apparatus is configured to demultiplex the first optical signal. The optical splitter is configured to split a demultiplexed first optical signal to obtain a first sub-signal and a second sub-signal. The optical switching apparatus is configured to perform optical switching on the first sub-signal. The second port is configured to output a first sub-signal obtained after optical switching. The optical monitoring apparatus is configured to perform optical performance monitoring on the second sub-signal.

An example optical switch includes a plurality of input ports and a plurality of output ports, a cross-connect fabric having one or more inputs, one or more outputs, and a device to selectively cross-connect the inputs with the outputs. The optical switch includes an integrated fast optical switch comprising a first input, a first output, and a second output, wherein the first input is connected to a first one of the outputs of the cross-connect fabric, and wherein the integrated fast optical switch has a switching time that is less than a switching time of the cross-connect fabric to switch the first input between the first output on a path to a first output port of the plurality of output ports and the second output on a path to a second output port of the plurality of output ports.

A node device capable of optimal transfer in accordance with the traffic situation of a network irrespective of the optical signaling system is provided. The node device includes a first wavelength selective switch connected to an input-side optical fiber; a fast selective switch connected to the first wavelength selective switch for cut-through or selective switching to an OCS controller or an OFS/OPS controller; an optical coupler connected to a cut-through output of the fast selective switch, an output of the OCS controller, and an output of the OFS/OPS controller; a second wavelength selective switch connected to an output of the optical coupler; and a node controller that performs wavelength assignment control for the first and second wavelength selective switches, path/label switch control for the fast selective switch, and flow/packet switch control for the OFS/OPS controller.

An optical communication apparatus includes an optical switch, a wavelength management control unit, and an optical switch control unit. The optical switch is connected to a plurality of transmission lines and outputs an optical signal input from one of the transmission lines to another of the transmission lines. The wavelength management control unit assigns a wavelength to a subscriber terminal according to a communication destination. The optical switch control unit controls the optical switch such that it outputs an optical signal transmitted from the subscriber terminal, to which a wavelength has been assigned, to a transmission line corresponding to its forwarding destination on a path to the communication destination.

Access nodes of a large-scale network are arranged into a number of groups. The groups are arranged into a number of bands. Each distributor of a pool of distributors interconnects each access node of a selected group to at least one channel from each group of a selected band. A discipline of allocating the selected group and the selected band to a distributor ensures that each access node has: a number, approximately equal to half the number of groups, of parallel single-hop paths to each other access node of a same group; a number, approximately equal to half the number of bands, of parallel single-hop paths to each access node of a different group within a same band; and one single-hop path to each other access node of a different access band. To eliminate the need for cross connectors, geographically-spread distributors are arranged into geographically-spread constellations of collocated distributors.

An optical routing system for free space optical communication is disclosed. The system has a transmitter and a receiver that use free space optical communication, and includes an optical path based on waveguide where an optical signal is routed from the proximity of the transmitter to the proximity of the destination. This system has advantages in terms of mitigating line-of-sight issues, as well as potentially reducing the overall coupling loss that would be otherwise incurred due to beam divergence of free space propagation for long distance.

A passive signal transport medium, constructed as an array of spectral-temporal connectors, connects a large number of access nodes to a number of distributors to form a single-hop network of wide coverage and high throughput yet simplified control. Parameterized spectral-temporal connectors define network expansion over networks using conventional signal transport media. A network accommodating 32000 access nodes with a throughput of an Exabits/second is realizable. The distributors may be geographically distributed (the access nodes are naturally geographically distributed). The entire network structure is parameterized. Selecting the number of distributors to equal the number of access nodes, and pairing each access node with a respective distributor to form an integrated node, an expanded fully-meshed network is realized with each pair of integrated nodes having a direct path and numerous single-hop paths. Several routing schemes within the fully-meshed network are considered to enable both global control and distributed control.

A network switch is capable of supporting cut-through switching and interface channelization with enhanced system performance. The network switch includes a plurality of ingress tiles, each tile including a virtual output queue (VOQ) scheduler operable to submit schedule requests to a fabric scheduler. Data is requested in unit of quantum, which may aggregate multiple packets, and which reduces schedule latency. Each request is associated with a start-of-quantum (SoR) state or a middle-of-quantum (MoR) state to support cut-through. The fabric scheduler performs a multi-stage scheduling process to progressively narrow the selection of requests, including stages of arbitration in virtual output port level, virtual output port group level, tile level, egress port level, and port group level. Each tile receives the grants for its requests and accordingly sends request data to a switch fabric for transmission to the destination egress ports.

A network system for a data center is described in which a switch fabric provides interconnectivity such that any servers may communicate packet data to any other of the servers using any of a number of parallel data paths. Moreover, according to the techniques described herein, edge-positioned access nodes, permutation devices and core switches of the switch fabric may be configured and arranged in a way such that the parallel data paths provide single L2/L3 hop, full mesh interconnections between any pairwise combination of the access nodes, even in massive data centers having tens of thousands of servers. The access nodes may be arranged within access node groups, and permutation devices may be used within the access node groups to spray packets across the access node groups prior to injection within the switch fabric, thereby increasing the fanout and scalability of the network system.