Abstract: An optical network includes an optical ring and at least three subnets. Each subnet includes a plurality of add/drop nodes coupled to the optical ring. The add/drop nodes are operable to passively add a first traffic stream in a first direction on the optical ring and a second traffic stream in a second direction on the optical ring. The first traffic stream comprises different content than the second traffic stream, and the first traffic stream and the second traffic stream are transmitted on the same wavelength. The network also includes a plurality of gateway nodes. The gateway nodes are each coupled to the optical ring at a boundary between neighboring subnets and are operable to selectively pass and terminate wavelengths between subnets to allow wavelength reuse in the subnets.

Abstract: A method and a system for setting a tunable filter in an optical network are provided. In one embodiment, a method for setting a tunable filter in an optical network includes rejecting a reference wavelength using a fixed filter from an input optical signal to generate a passthrough optical signal. A tunable filter is adjusted to maintain the tunable filter at the reference wavelength. The tunable filter is adjusted to a selected wavelength based on a determination of the reference wavelength.

Abstract: An optical network includes a plurality of subnets. The subnets each include a plurality of add/drop nodes coupled to the optical ring and operable to passively add and drop traffic to and from the optical ring. The network further includes a plurality of gateway nodes. The gateway nodes are each coupled to the optical ring at a boundary between neighboring subnets and operable to selectively pass and terminate wavelengths between subnets to allow wavelength reuse in the subnets and to provide protection switching.

Abstract: A flexible open ring optical network includes a plurality of nodes connected by twin or other suitable optical rings. Each node is operable to passively add and passively drop traffic from the rings. The nodes may include a transport element for each ring. The transport elements include an optical splitter element and an optical combiner element. The optical splitter element is operable to passively combine an add signal including local add traffic and a first transport signal including ingress traffic from a coupled optical ring to generate a second transport signal including egress traffic for transmission on the coupled optical ring. The optical combiner element is coupled to the optical splitter element and is operable to passively split a third transport signal including the ingress traffic to generate a drop signal including local drop traffic and a fourth transport signal including the ingress traffic.

Abstract: A device for directing one or more optical channels includes one or more micromirror elements. A micromirror element has a mirror and a mirror controller. The mirror is operable to reflect light at a first interaction area to yield a first passband for an optical channel, and to reflect light at a second interaction area to yield a second passband for the optical channel. The mirror controller operates to position the mirror at a first position at which light interacts with the first interaction area to yield the first passband, and to position the mirror at a second position at which light interacts with the second interaction area to yield the second passband.

Abstract: A flexible open ring optical network includes a plurality of nodes connected by twin or other suitable optical rings. Each node is operable to passively add and passively drop traffic from the rings. The nodes may include a transport element for each ring. The transport elements include an optical splitter element and an optical combiner element. The optical splitter element is operable to passively combine an add signal including local add traffic and a first transport signal including ingress traffic from a coupled optical ring to generate a second transport signal including egress traffic for transmission on the coupled optical ring. The optical combiner element is coupled to the optical splitter element and is operable to passively split a third transport signal including the ingress traffic to generate a drop signal including local drop traffic and a fourth transport signal including the ingress traffic.

Abstract: An optical cross-connect includes multiple input ports that each receives an optical input signal and multiple output ports that each output an optical output signal. The optical cross-connect also includes a distributing amplifier associated with each input port that generates multiple copies of the input signal received at the associated input port and multiple filter units that receive one or more of the copies and forward traffic in selected channels of particular copies. In addition, the optical cross-connect includes a combining amplifier associated with each output port that receives the traffic forwarded by one or more of the filter units and combines the received traffic into an output signal. Moreover, the optical cross-connect includes at least one upgrade input port and at least one upgrade output port expanding the capacity of the optical cross-connect, as well as associated upgrade distributing and combining amplifiers and upgrade filter units.

Abstract: A device for directing one or more optical channels includes one or more micromirror elements. A micromirror element has a mirror and a mirror controller. The mirror is operable to reflect light at a first interaction area to yield a first passband for an optical channel, and to reflect light at a second interaction area to yield a second passband for the optical channel. The mirror controller operates to position the mirror at a first position at which light interacts with the first interaction area to yield the first passband, and to position the mirror at a second position at which light interacts with the second interaction area to yield the second passband.

Abstract: The invention provides an optical fiber amplifier which assures stable operation of a pump light source and efficiently makes use of residual pump power to achieve improvement in conversion efficiency. The optical fiber amplifier includes a rare earth doped fiber. Pump light from a pump light source is introduced into one end of the rare earth doped fiber by way of a first optical coupler, and residual pump light originating from the pump light and arriving at the other end of the rare earth doped fiber is applied to the other rare earth doped fiber amplifier or the loss compensation of a dispersion compensating fiber by Raman amplification.

Abstract: A multi-wavelength light amplifier includes a first-stage light amplifier which has a first light amplifying optical fiber amplifying a light input, a second stage light amplifier which has a second light amplifying optical fiber amplifying a first light output from the first-stage light amplifier, and an optical system which maintains a second light output of the second-stage light amplifier at a constant power level.

Abstract: A method for compensating for optical dispersion in an optical signal includes receiving an optical signal comprising a plurality of channels. The information being communicated in a first set of channels is modulated using a first modulation technique, and the information being communicated in a second set of channels is modulated using a second modulation technique. The method also includes compensating for optical dispersion in the optical signal such that dispersion compensation for the first set of channels is complete and such that dispersion compensation for the second set of channels is incomplete. In addition, the method includes splitting the optical signal into a first copy and a second copy, terminating the second set of channels in the first copy, performing additional dispersion compensation on the second copy such that dispersion compensation for the second set of channels is complete, and terminating the first set of channels in the second copy.

Abstract: A flexible open ring optical network includes a plurality of nodes connected by twin or other suitable optical rings. Each node is operable to passively add and passively drop traffic from the rings. The nodes may include a transport element for each ring. The transport elements include an optical splitter element and an optical combiner element. The optical splitter element is operable to passively combine an add signal including local add traffic and a first transport signal including ingress traffic from a coupled optical ring to generate a second transport signal including egress traffic for transmission on the coupled optical ring. The optical combiner element is coupled to the optical splitter element and is operable to passively split a third transport signal including the ingress traffic to generate a drop signal including local drop traffic and a fourth transport signal including the ingress traffic.

Abstract: An optical amplifier which amplifies a wavelength division multiplexed (WDM) optical signal having a variable number of channels associated with different wavelengths and outputs the amplified WDM optical signal. The optical amplifier includes (a) an optical attenuator which controls a level of the amplified WDM optical signal, and (b) a controller which controls the WDM optical signal to be amplified with an approximately constant gain.

Abstract: A multi-wavelength light amplifier includes a first-stage light amplifier which has a first light amplifying optical fiber amplifying a light input, a second-stage light amplifier which has a second light amplifying optical fiber amplifying a first light output from the first-stage light amplifier, and an optical system which maintains a second light output of the second-stage light amplifier at a constant power level. The first-stage and second-stage light amplifiers have different gain vs wavelength characteristics so that the multi-wavelength light amplifier has no wavelength-dependence of a gain thereof.

Abstract: A system and method for assigning a traffic channel to a wavelength in a multi-ring optical network having bifurcated work and protect wavelengths includes determining a transport direction for the traffic channel in a ring of the multi-ring optical network. An inter/intra ring type of the traffic channel is determined. The traffic channel is assigned to a wavelength in the ring based on the transport direction and the inter/intra ring type of the traffic channel. In a particular embodiment, the traffic channel may be assigned to one of an odd and even wavelength based on the transport direction and one of a high and low wavelength based on the inter/intra ring type.

Abstract: An optical network includes an optical ring and a plurality of add/drop nodes coupled to the optical ring. Each of the add/drop nodes is operable to passively add and drop one or more traffic streams to and from the optical ring, and each traffic stream comprises a channel. A hub node also coupled to the optical ring is operable to selectively pass and terminate individual traffic streams.

Abstract: The present invention aims at providing a method for controlling wavelength characteristics of optical transmission powers by Raman amplification, in which the wavelength characteristics of optical transmission powers are automatically compensated without giving any losses to channel lights to thereby improve transmission characteristics, and an apparatus adopting the same. To this end, the method for controlling wavelength characteristics of optical transmission powers by Raman amplification according to present invention supplies Raman pump light to an optical transmission path (Raman amplifying medium); compensates the wavelength characteristics of optical transmission powers caused by transmission of WDM signal light through the optical transmission path, by gain wavelength characteristics of generated Raman amplification; and monitors the wavelength characteristics of optical transmission powers after Raman amplification to thereby control the gain wavelength characteristics of Raman amplification.

Abstract: Reducing polarization dependence of a dispersion variation monitor includes receiving an optical signal. The optical signal is split into a first polarized signal having first photons and a second polarized signal having second photons. The first photons are received at a first material of a first detector, where the first material is operable to produce a reaction in response to the arrival of a predetermined number of photons. The second photons are received at a second material of a second detector, where the second material is substantially similar to the first material. A first current produced by the first material in response to receiving the first photons and a second current produced by the second material in response to receiving the second photons are monitored. Whether there is wavelength dispersion variation among the plurality of components is established in accordance with the first current and the second current.

Abstract: A method for transmitting traffic in an optical network includes establishing a light-trail in the optical network between a number of nodes. The light-trail couples the nodes and is associated with one of a number of wavelengths in the network. The method also includes, at one or more of the nodes, receiving traffic from one or more client devices of the node to be communicated over the light-trail to a destination node and determining one or more service types associated with the received traffic. Furthermore, the method includes determining traffic shaping information for each service type based on information relating to the arrival of traffic associated with the service type at the node. The traffic shaping information indicating to the destination node the rate at which the traffic associated with each service type should be communicated from the destination node to one or more client devices of the destination node.

Abstract: An optical network is provided that carries optical traffic in multiplexed wavelengths between a number of nodes. The network includes at least one light-trail associated with one of the wavelengths and established between a subset of the nodes in the network. The network also includes an out-of-band control channel that is associated with a different wavelength than the light-trail. The control channel is used to communicate control messages to establish the light-trail and to allocate use of the light-trail by the subset of nodes. Each of the subset of nodes comprises a burstponder operable to receive data traffic from one or more client devices of the associated node to be communicated over the light-trail and to buffer the received data traffic and assemble the data traffic into an optical payload.