An optical node may include an optical switch and an optical add drop multiplexer (OADM). The optical switch may receive, via a space-division multiplexing (SDM) link that carries optical signals via multiple SDM elements, an optical signal to be switched from a first SDM element to a second SDM element. The multiple SDM elements may include multiple cores of a multi-core fiber, multiple modes of a multi-mode fiber, or multiple fibers of a fiber bundle. The optical switch may switch the optical signal from the first SDM element to the second SDM element. The OADM may add optical signals to an optical network or drop optical signals from the optical network via one or more SDM links that include the SDM link.

An ONU receiving an optical signal from an OLT including PON controllers includes: an optical receiver to convert, into an electric signal, an optical signal having a single optical wavelength set out of plural optical wavelengths; and a control frame extractor to extract and hold wavelength correspondence information indicating correspondence between MAC addresses of the PON controllers received from the OLT and the optical wavelengths. The control frame extractor, when receiving a wavelength switching request, extracts the optical wavelength after wavelength switching instructed in the wavelength switching request, obtains a setting address of the MAC address of the PON controller to which the ONU itself should be connected after the wavelength switching based on the extracted optical wavelength after the wavelength switching and the wavelength correspondence information, and determines whether a malfunction occurs based on a transmission source MAC address stored in a received control frame and the setting address.

Example embodiments of the present invention relate to an optical signal processor comprising of at least one wavelength processing device, a plurality of optical amplifying devices, and a least one field programmable photonic device.

A transmission characteristics monitoring device monitors transmission characteristics of an optical transmission path between nodes. The device detects an average power of the frequency modulated optical signal and a slope of the transmission characteristics; generates a slope function that represents a slope of the transmission characteristics between first and second frequencies; generates a corrected power value by adding an integral of the slope function to a first power measurement value detected at the first frequency; calculates the transmission characteristics at the second frequency based on a second power measurement value detected at the second frequency when the difference between the second power measurement value and the corrected power value is smaller than a specified threshold; and calculates the transmission characteristics at the second frequency based on the corrected power value when the difference is greater than the specified threshold.

A high capacity node includes a plurality of transceivers each with a transmitter configured to support a wavelength within a full transparent window of one or more optical fibers; and one or more optical amplifiers covering the full transparent window, wherein the one or more optical amplifiers comprise one of (i) a single ultra-wideband amplifier covering the full transparent window and (ii) a plurality of amplifiers each supporting a different band of the full transparent window.

An integrated C+L band Reconfigurable Optical Add/Drop Multiplexer, ROADM, node (10B, 10C, 10D) supporting integrated C and L band functionality includes one or more ROADM modules (20CL, 20CLQ) each including a demultiplexer Wavelength Selective Switch, WSS, (102) having a common receive input and a plurality of output ports, a multiplexer WSS (104) having a plurality of input ports and a common transmit output, wherein, each of the demultiplexer WSS (102) and the multiplexer WSS support (104) both the C band and L band in an integrated manner, a plurality of amplifiers (106, 108, 11, 112, 114, 116) that each connect to one of the demultiplexer WSS (102) and the multiplexer WSS (104), and line ports including a transmit port (50T) and a receive port (50R) that connect to the plurality of amplifiers (106, 108, 110, 112, 114, 116).

Example embodiments of the present invention relate to an optical signal processor comprising of at least one wavelength processing device, a plurality of optical amplifying devices, and a least one field programmable photonic device.

Methods and apparatus for add-drop multiplexing in all optical networking are provided. A tunable optical filter is controlled to drop a first portion of an incoming optical signal in a first wavelength band and pass a second portion of the incoming optical signal in a second wavelength band. The dropped first portion is distributed among local drop optical output ports with a demultiplexer. A multiplexer combines local add optical input signals in a third wavelength band into an add optical input signal and the tunable optical filter is controlled to add the add optical input signal to the passed second portion of the incoming optical signal. The tunable optical filter is configured to lower an optical loss for the passed second portion of the incoming optical signal at the account of a corresponding increase of an optical loss in the dropped first portion and/or the add optical input signal.

A first reconfigurable optical add/drop multiplexers (ROADM) and a second ROADM are connected by a primary light path and a protection light path. The first ROADM includes a first direction and a second direction, and the second ROADM includes a third direction and a fourth direction. The primary light path is coupled between the first direction and the third direction, and the protection light path is coupled between the second direction and the fourth direction. Transmissions on the primary light path are monitored, and when a problem is detected on the primary light path, the first and third directions are deactivated and the second and fourth directions are activated so that additional light signals are sent on the protection light path and not on the primary light path.

A wavelength division multiplexed optical communication system includes a plurality of optical line terminals which may be part of separate in service networks, each having a line interface and an all-optical pass-through interface including a plurality of pass-through optical ports, and each also including a plurality of local optical ports which are connectable to client equipment and an optical multiplexer/demultiplexer for multiplexing/demultiplexing optical wavelengths. The optical multiplexer/demultiplexer may include one or more stages for inputting/outputting individual wavelengths or bands of a predetermined number of wavelengths, or a combination of bands and individual wavelengths. At least one of the pass-through optical ports of an optical line terminal of one network may be connected to at least one of the pass-through optical ports of an optical line terminal of another network to form an optical path from the line interface of the optical line terminal of the one network to the line interface of the optical line terminal of the another network to form a merged network. The use of such optical line terminals allows the upgrading and merging of the separate networks while in service.