An optical system is provided that converts optical signals received over an optical trunk from a first optical switch to client optical signals intended for a second optical switch. The first and second optical switches operate in accordance with a Fiber Channel (FC) protocol. An interruption of the optical signals on the optical trunk is detected. Responsive to the interruption, a Not Operational State (NOS) message sent to the second optical switch is delayed so as to delay triggering of an FC link initialization in the second optical switch. While the NOS message is delayed, idle messages are sent to the second optical switch.

According to embodiments of the present disclosure, apparatus is provided for protecting an optical link arranged to carry upstream optical signals and downstream optical signals. The apparatus comprises a first detector arranged to selectively detect a downstream optical signal received at a second port having a first wavelength and a second detector arranged to selectively detect a downstream optical signal received at the second port having a second wavelength different from the first wavelength. The apparatus further comprises control circuitry arranged to cause a protection switch to selectively couple a third port to the second port instead of to the first port based on the detecting by the first detector and the second detector. Also provided is a second apparatus for protecting the optical link. The second apparatus comprises a bypass element arranged to selectively direct at least a portion of an upstream optical signal at the first wavelength, received at a fourth port, such that a downstream optical signal at the first wavelength is transmitted from a fifth port.

Client-side protection systems and methods are implemented by a network element using a fast electrical squelch with a first optical transceiver and a second optical transceiver. A client-side protection method includes detecting a protection switching event affecting one or more lanes associated with the first optical transceiver; causing a fast electrical squelch to the affected one or more lanes of the first optical transceiver to provide a Loss of Signal (LOS) thereto; and subsequent to the LOS to the first electrical transceiver, causing a fast electrical squelch to corresponding one or more lanes of the second optical transceiver to enable the corresponding one or more lanes thereon.

A method and an apparatus for hot standby of controllers in distributed protection are provided. In some embodiments, the method includes: through an actuator, receiving a message transmitted from each of the controllers; determining the messages transmitted in response to a same fault according to a serial number of each message, maintaining a master-standby relationship of each of the controllers through the messages transmitted in response to the same fault; and executing a corresponding operation according to a message transmitted from a master controller; and in a protocol steady state, performing a master-standby switching if it is determined that a switching condition is met.

The embodiments of the invention relate to a line switching component separable from a line card of a network node. The line switching component contains at least one input port for receiving an optical input signal from an optical transport network and at least one output port for transmitting an optical output signal to the optical transport network. The line switching component further contains at least one further output port configured to be connected to an input port of at least one optical interface of the line card and at least one further input port configured to be connected to an output port of the at least one further optical interface of the line card. The line switching component further contains a switchable optical path system configured to operate the line switching component in a first operation mode and to operate the line switching component in a second operation mode.

The present disclosure discloses a method and device for channel switching, an Optical Network Unit (ONU) and a system for Time Wavelength Division Multiplexing (TWDM). The method for channel switching includes that: an ONU acquires channel information of a first TWDM channel, wherein the channel information of the first TWDM channel is used for indicating an uplink wavelength and/or downlink wavelength of the first TWDM channel; and the ONU tunes the uplink wavelength and/or downlink wavelength of the ONU into the uplink wavelength and/or downlink wavelength of the first TWDM channel according to the channel information of the first TWDM channel. By means of the present disclosure, the problem of high cost caused by specially building a standby channel for each TWDM channel in a system for TWDM Passive Optical Network (PON) to provide service protection is solved, and the cost of deploying the TWDM PON system is reduced.

An optical device having a self-repair component capable of curing a defective component(s) is disclosed. To improve reliability as well as manufacturing yield, a photonic integrated circuit (PIC) for as a multi-channel optical line terminal (OLT) contains spare lasers or standby lasers configured to replace a failed laser(s). In one aspect, PIC includes a set of fixed-wavelength lasers (FWLs), a tunable-wavelength auxiliary laser (TWAL), a photonic detector, and a tuner. FWLs, for example, generate optical wavelengths representing optical signals. TWAL generates an optical signal with a spectrum of wavelengths based on a setting generated by the tuner. The photonic detector detects a defective wavelength. The tuner adjusts output wavelength of TWAL in response to the defective wavelength. Alternatively, PIC includes a working laser array, standby laser array, and spare laser array capable of providing two layer laser defective protections.

Client-side protection systems and methods are implemented by a network element using a fast electrical squelch with a first optical transceiver and a second optical transceiver. A client-side protection method includes detecting a protection switching event affecting one or more lanes associated with the first optical transceiver; causing a fast electrical squelch to the affected one or more lanes of the first optical transceiver to provide a Loss of Signal (LOS) thereto; and subsequent to the LOS to the first electrical transceiver, causing a fast electrical squelch to corresponding one or more lanes of the second optical transceiver to enable the corresponding one or more lanes thereon.

There is provided a transmission device including a hardware processor configured to receive an alarm for each of paths, and generate an interrupt request, when a series of alarms is received at a time interval equal to or less than a predetermined value and a last alarm of the series of alarms is received, a memory, and a processor coupled to the memory and the processor configured to switch the path, provided on a transmission line in an active system and from which the alarm is received, from the active system to a standby system in response to the interrupt request generated by the hardware processor.

A fiber optic network (10) includes a mobile switching center (MSC) (12) which distributes fiber optic signals to one or more remote cabinets (40, 42, 44). The remote cabinets (40, 42, 44) distribute signals to one or more customers. The cabinets (40, 42, 44) receive service from the MSC (12) or from a temporary service provider, such as a vehicle (500), in the event of a catastrophic failure of the MSC (12). The cabinets (40, 42, 44) include equipment which allows patching to a temporary service provider through a patch panel (200), and sub-racks (154, 156, 158) and supporting cabling (134, 136) to provide service to each of the cabinets in the network.