Systems and methods of sharing optical spectrum between a plurality of users of a submarine optical system includes receiving one or more optical signals from the plurality of users of the submarine optical system, wherein each of the plurality of users are assigned a slice of optical spectrum on the submarine optical system; monitoring each of the one or more optical signals to determine compliance with one or more constraints; and adding the one or more optical signals to the submarine optical system if compliant with the one or more constraints.

A redundancy system for data transport in a Distributed Antenna System (DAS) includes a plurality of Digital Access Units (DAUs). Each of the plurality of DAUs is fed by a plurality of data streams and is operable to transport digital signals between others of the plurality of DAUs. The redundancy system also includes a plurality of Digital Distribution Units (DDUs). Each of the plurality of DDUs is in communication with each of the plurality of DAUs using cross connection communication paths. The redundancy system further includes a plurality of Digital Remote Units (DRUs). Each of the plurality of DRUs is in communication with each of the plurality of DDUs using cross connection communications paths.

A content delivery network (CDN) includes: at least one CDN origin node; and multiple CDN cache nodes connected to the at least one CDN origin node via an optical transport network (OTN). Deliveries and/or routing from the multiple CDN cache nodes to the at least one CDN origin node and/or vice versa is performed below layer 3 of the Open Systems Interconnection (OSI) model.

An optical network unit (ONU) comprising a media access controller (MAC) configured to support biasing a laser transmitter to compensate for temperature related wavelength drift receiving a transmission timing instruction from an optical network control node, obtaining transmission power information for the laser transmitter, estimating a burst mode time period for the laser transmitter according to the transmission timing instruction, and calculating a laser phase fine tuning compensation value for the laser transmitter according to the burst mode time period and the transmission power information, and forwarding the laser phase fine tuning compensation value toward a bias controller to support biasing a phase of the laser transmitter.

An optical receiver includes: a tunable filter configured to partially transmit a wavelength-multiplexed optical-signal including a first optical-signal having a first wavelength, a second optical-signal having a second wavelength, and a third optical-signal having a third wavelength, with a frequency-modulated signal superimposed on each of the first to third optical-signals; a photo detector configured to detect an optical-power of the wavelength-multiplexed optical-signal transmitted through the tunable filter; and a superimposed signal detector configured to detect the frequency-modulated signal superimposed on the first optical-signal, based on an amplitude-modulated signal according to a variation in the optical-power on a first filter setting where both of the first optical-signal and the second optical-signal transmit through the tunable filter, and an amplitude-modulated signal according to a variation in the optical-power on a second filter setting where both of the first optical-signal and the third optical-signal transmit through the tunable filter.

A co-packaged optical module includes a substrate, a processor arranged on the substrate and a plurality of light engines mounted around the processor on the substrate using mounting assemblies configured to attach the respective light engines to the substrate. The light engines and the mounting assemblies are disposed along a perimeter of the substrate, including at corners of the substrate. Each of the mounting assemblies includes a socket, a metal clamp clamping a corresponding one of the light engines into the socket, and a plurality of pins which when mated with corresponding holes in the substrate cause peripheries of the mounting assemblies, including the light engines, the sockets and the metal clamps, to be flush with the perimeter of the substrate.

A control apparatus includes an optical wavelength change control unit that specifies, in response to a request to change a wavelength band of a first optical wavelength path used by a first transmission apparatus and a second transmission apparatus to a wavelength band of a second optical wavelength path, a first route between routers which is affected by the request and a service which uses the first route and that specifies a second route between the routers which detours the specified service; a router control unit that transmits a request to detour the specified service to the second route, to a start-point router and an end-point router on the first route; and a transmission apparatus control unit that transmits a request to change the wavelength band of the first optical wavelength path to the wavelength band of the second optical wavelength path, to the first transmission apparatus and the second transmission apparatus.

Vector and matrix multiplications can be accomplished in photonic circuitry by coherently combining light that has been optically modulated, in amplitude and/or phase, in accordance with the vector and matrix components. Disclosed are various beneficial photonic circuit layouts characterized by loss- and delay-balanced optical paths. In various embodiments, loss balancing across paths is achieved with suitable optical coupling ratios and balanced numbers of waveguide crossings (using dummy crossings where needed) across the paths. Delays are balanced in some embodiments with geometrically delay-matched optical paths.

The invention relates to an optoelectronic transceiver device comprising a first optical connector (OC1) capable of connection to a first bidirectional optical fibre (OF1), and a second optical connector (OC2) capable of connection to a second bidirectional optical fibre (OF2), the device further comprising: an insertion-extraction module (ADM) capable of: extracting a wave-length (λ.sub.Rx) from a plurality of wavelengths constituting a first optical signal received by the first optical connector (OC1) and transmitting the first optical signal without the extracted wavelength to the second optical connector (OC2); inserting a wavelength (λ.sub.Tx) into a second optical signal received by the second optical connector (OC2) and transmitting the second optical signal with the inserted wavelength to the first optical connector (OC1); an electric-optical conversion module (EC1) capable of providing the insertion-extraction module with the wavelength (λ.sub.Tx) inserted into the second optical signal from an incoming electric signal (Data Tx); and an optical-electric conversion module (EC2) capable of converting the wavelength (λ.sub.Rx) extracted from the first optical signal by the insertion-extraction module into an outgoing electric signal (Data Rx).

A method and apparatus is described for estimating a local oscillator frequency offset (LOFO) of a received optical signal in a coherent optical receiver. The method includes receiving a signal by the coherent optical receiver; digitally shifting a spectrum of the received signal according to one of a plurality of frequency shifts within a first range; equalizing each shifted signal based on a hybrid shifted filter response of a receiver driver, the hybrid shifted filter response is based on a combination of a linear shifted response and a circular shifted filter response of the receiver driver; calculating a difference of power between two sides of a spectrum of each equalized signal, the power for each side of the spectrum being calculated within a first area centered around a frequency corresponding to half of a baud rate of the received signal; determining a minimum power difference among the plurality of frequency shifts within the first range; and estimating the LOFO based on the minimum power difference.