Described are various configurations of reduced crosstalk optical switches. Various embodiments can reduce or entirely eliminate crosstalk using a coupler that has a power-splitting ratio that compensates for amplitude imbalance caused by phase modulator attenuation. Some embodiments implement a plurality of phase modulators and couplers as part of a dilated switch network to increase overall bandwidth and further reduce potential for crosstalk.

An intersecting splitter configured so that the branching ratio of each optical splitter differs in accordance with the difference in the number of intersections in each branched waveguide. The branching ratios (totaling 100%) of the optical splitters are adjusted so that the branching ratios on the high side as to the number of intersections is high in comparison with the branching ratios on the low side as to the number of intersections, and it is thereby possible to level the total loss.

Aspects of the disclosure involve a source node, having some predetermined knowledge of the optical network generating a list of nodes and/or optical links between nodes that form a route in the optical network from the source node to the destination node. The nodes in the optical network do not necessarily need to know the entire route from source node to destination node. Each node simply decodes the control information identifying the next hop in the route towards the destination node. By utilizing the decoded control information identifying the next hop, a switch in the node can be controlled to route the optical signal including the payload and some or all of the control information onto the next optical link toward the destination node.

An optical trunk switch is configured to support an OTDR. The system includes a transmit switch having two inputs and outputs, the first input is configured to connect to a signal input, the second input is configured to receive a OTDR signal, the first output is configured to connect to one of a primary fiber and a standby fiber, and the second output is configured to connect to the other fiber. The system further includes a receive switch having two inputs and outputs, the first input is configured to connect to one of the primary fiber and the standby fiber, the second input is configured to connect to the other fiber, the first output is configured to connect to a signal output, and the second output is configured to connect to a OTDR signal; and one or more OTDR ports.

In order to realize a variable equalizer which is compact and has a wide range of tilt level adjustment, this variable equalizer is provided with a first optical equalizer group including a plurality of first equalizers having mutually different tilt amounts, a second optical equalizer group including a plurality of second equalizers, and an optical element for forming the optical path of an optical signal so that an inputted optical signal is outputted passing through a selected first optical equalizer and a selected second optical equalizer, at least one of the plurality of second optical equalizers having a tilt amount different from any of the plurality of first optical equalizers.

As network traffic grows and more data needs to be transmitted through a network, it is desired to use optical switching systems that allow for switching between a large number of nodes. An optical switching system according to one embodiment disclosed herein allows different nodes to transmit optical signals having the same optical wavelength, in order to accommodate a larger number of nodes. For example, one cluster of nodes may transmit data using optical wavelengths that are the same as optical wavelengths that may also be used by other clusters of nodes. A controller performs scheduling and reconfiguration in the optical switching system, as needed, e.g. in order to mitigate collisions.

A transmitter can include a laser operable to output an optical signal; a digital signal processor operable to receive data and provide a plurality of electrical signals based on the data; and a modulator operable to modulate the optical signal to provide a plurality of optical subcarriers based on the plurality of electrical signals. One of the plurality of subcarriers carries first information indicative of a first portion of the data in a first time slot and second information indicative of a second portion of the data in a second time slot. The first information is associated with a first node remote from the transmitter and the second information is associated with a second node remote from the transmitter. A receiver as well as a system also are described.

An optical add-drop apparatus dropping a signal in input optical fibers in an optical cross-connect apparatus or adding a signal into output optical fibers from the cross-connect apparatus, optical cross-connect portions of the cross-connect apparatus connected such that a cross-connect portion internal connection output port is directly connected to an internal connection input port of another cross-connect portion and is indirectly connected via the other cross-connect portion to an internal connection output port of a further cross-connect portion, the add-drop apparatus having: photocouplers connected to part or all of the input fibers connected to each cross-connect portion; and drop signal receiving apparatuses each having optical switches each receiving and alternately selecting a signal output from photocouplers connected to respective different cross-connect portions of the cross-connect portions out of the photocouplers, the drop signal receiving apparatuses selecting a signal of a wavelength for each signal respectively output from the optical switches.

Methods and apparatus for providing enhanced optical networking service and performance which are particularly advantageous in terms of low cost and use of existing infrastructure, access control techniques, and components. In the exemplary embodiment, current widespread deployment and associated low cost of Ethernet-based systems are leveraged through use of an Ethernet CSMA/CD MAC in the optical domain on a passive optical network (PON) system. Additionally, local networking services are optionally provided to the network units on the PON since each local receiver can receive signals from all other users. An improved symmetric coupler arrangement provides the foregoing functionality at low cost. The improved system architecture also allows for fiber failure protection which is readily implemented at low cost and with minimal modification.

The present invention provides a receiving device and an optical switching fabric apparatus, where the receiving device includes: multiple selecting modules, a fast optical switch connecting to each selecting module, an output module connecting to all the fast optical switches, and a receiver connecting to the output module, where the selecting module is configured to receive a multiwavelength optical signal, select and filter a first optical signal of a preset time segment in the multiwavelength optical signal; the fast optical switch is configured to select a second optical signal from the first optical signal filtered by the selecting module; the output module is configured to combine optical signals separately selected by all the fast optical switches into one optical burst signal; and the receiver is configured to perform optical-to-electrical conversion on the optical burst signal, and extract service data from an electrical signal.