Abstract: An apparatus for selectively adjusting power levels of component signals of a wavelength division multiplexed signal. The apparatus comprises a first filter and a second filter. The first filter modulates the component signals according to a static attenuation profile, thereby providing coarsely modulated component signals. The second filter is coupled to the first filter to receive the coarsely modulated component signals and to modulate the coarsely modulated component signals according to a dynamic attenuation profile, thereby providing finely modulated component signals.

Abstract: An optical modulation processing section is provided which, in turn, includes a signal carrier-suppressed pulse modulating unit that performs signal carrier-suppressed pulse modulation on a light source signal to thereby create a CS-RZ signal, a phase modulating unit that performs phase modulation on a data signal based on the CS-RZ signal to thereby convert the data signal to a phase-modulated signal, and an optical filtering unit that filters out redundant frequency components included in the phase modulation signal.

Abstract: An apparatus and method are provided for transmitting an optical duobinary signal using a low bandwidth modulator having a bandwidth of less than about 60% of the transmission bit rate of the transmitter. The modulator is adapted to provide low pass filtering for low pass filtered duobinary transmission in an optical fiber transmission system having residual dispersion.

Abstract: An optical duobinary transmission system and method are provided for transmitting optical duobinary signals across an optical transmission link having residual dispersion. The system includes a transmitter having a low bandwidth modulator, adapted to provide filtering for low pass filtered duobinary transmission. The transmission link is designed such that the residual dispersion of the transmission link substantially compensates for signal distortion from the transmitter.

Abstract: A method of wavelength selection control is disclosed.

Abstract: A bi-directional configuration is employed to implement a hybrid ultra long haul (ULH)/long haul (LH) optical transmission system. The link carries ULH channels and LH channels in opposite directions in different bands. Raman amplification is employed for the ULH band while Erbium-doped fiber amplification (EDFA) is used for both the LH and ULH bands. Optical circulators are employed for multiplexing and demultiplexing. This solution does not incur the ripple penalty of prior art solutions based on interferential filters while providing excellent isolation between the ULH and LH channels and bi-directional communication within a single fiber.

Abstract: A method and apparatus for determining the dispersion characteristics of minimum phase filters using substantially only an amplitude response of a minimum phase filter under test includes fitting an amplitude spectrum of the minimum phase filter with a substantially straight line curve, and determining the dispersion characteristics of the minimum phase filter using the straight line curve and the relationships determined by the inventors. Various inventive equations determined by the inventors representative of the relationship between an amplitude response of a minimum phase filter and the dispersion characteristics of the minimum phase filter are used for determining the dispersion characteristics of the minimum phase filter.

Abstract: A reconfigurable optical add-drop multiplexer is disclosed that enables Optical Multiplex Section (OMS) shared protection rings. The ROADM comprises a first optical supervisory module, coupled to a first amplifier module, which in turn is coupled to a first broadcast and select module, where the first broadcast and select module is coupled to both a first multiplexer/demultiplexer module and the first optical supervisory module. Each optical supervisory module has an optical tap for tapping a fraction of an outgoing OMS signal that is fed back or looped back to a 2×1 optical switch in the optical supervisory module.

Abstract: A method of controlling phase alignment in a modulator of a transmitter in an optical communications system uses a narrowband optical filter to monitor changes in power spectral density of a modulated output at and around the optical carrier frequency. In one embodiment, a method controls alignment of a carrier-suppressed-return-to-zero (CSRZ) pulse train in accordance with changes in the power spectral density of the CSRZ modulated optical signal at and around the optical carrier frequency and generates phase adjustment control signals by executing a phase-control loop to maintain the power spectral density of the CSRZ modulated output at the optical carrier frequency at a desired level.

Abstract: A PON and a method of transmitting data employing different upstream and downstream transmission protocols are disclosed. The PON includes: a plurality of ONTs; WDM filters; an OLT receiving and transmitting optical signals to and from the ONTs and a higher network; and an optical coupler. The ONT includes a first switching unit, a level transformer converting two level Ethernet signals into a three level data signals, a first code generator generating a specific CDMA codes that distinguish the ONT from another ONT, and a first multiplier performing a spread spectrum function with the CDMA codes. The OLT includes an optical receiver, a branching filter branching the upstream CDMA signals, a plurality of second code generators generating codes for despread, a plurality of second multipliers multiplying the received signals by the despread codes, and a plurality of data decider extracting data through correlation calculation.

Abstract: An optical network unit (ONU) interconnected by passive optical network (PON) equipment to an optical line terminal (OLT) is identified using secondary modulation of the optical carrier to impress an identifier of the ONU onto the carrier. This resolves a recurring ONU failure mode detection problem caused by failure of a laser driver that causes the ONU to be stuck in an on state.

Abstract: A multi-layer photonic network and nodes used therein are provided. The multi-layer photonic network comprises a packet network which performs switching and transfer in packet units, and a photonic network comprising optical transmission lines and photonic switches, and which accommodates the packet network. The multi-layer photonic network also has a two layer structure of optical wavelength links (O-LSPs) and packet links (E-LSPs). The O-LSPs are constituted by the optical transmission lines and comprise optical wavelength switching capability (LSC) which is capable of switching in optical wavelength units and packet switching capability (PSC) which is capable of switching in packet units at both their ends. The E-LSPs include the O-LSPs and PSCs at both their ends. Each node includes a section for automatically establishing an O-LSP according to an establishment request for an E-LSP while taking account of path information including path cost, resource consumption, and traffic quantity.

Abstract: An optical add and drop multiplexer system comprising a first module for providing a first signal; a second module for providing a second signal; and a modulator for receiving a channel of the first signal at a first location, the first location configured to actuate between a first configuration and a second configuration, wherein the modulator directs the channel of the first signal as an output signal when the first location is in the first configuration. The modulator may direct the channel of the first signal as a dropped signal when the first location is in the second configuration. The modulator may also receive a channel of the second signal from the second module at a second location configured to independently actuate between the first configuration and the second configuration.

Abstract: Disclosed is an integrated circuit comprising a plurality of cores attached to at least one transmitter and receiver, an optical transmission network embedded within the wire levels of the integrated circuit, and wherein the transmitter and receivers send and receive data on the network. Also disclosed is a method of transmitting signals within an integrated circuit comprising an integrated circuit comprising a plurality of cores and optical paths, selecting an optical path from the plurality of optical paths for transmitting data, and transmitting the data on the selected optical path. Also disclosed is an integrated circuit comprising an optical transmission network, a plurality of cores, and a plurality of controllers, all three being operatively attached to each other.

Abstract: An OADM includes optical input and output; first and second bandpass filters with a first pass band, optically coupled to the optical input and output, respectively; third and fourth bandpass filters with a second pass band, optically coupled to reflection ports of the first and second bandpass filters, respectively; first and second cascaded series of channel filter assemblies optically coupled to the transmission ports of the first and second bandpass filters, respectively, and third and fourth cascaded series of channel filter assemblies optically coupled to the transmission ports of the third and fourth bandpass filters, respectively. The OADM may be extended or upgraded so as to accommodate the throughput of additional channels or wavelengths by extending the number of filters within each cascaded series of bandpass filters, where the transmission ports of the additional bandpass filters are optically coupled to respective additional cascaded series of channel filter assemblies.

Abstract: A system, including: a source node apparatus; a destination node apparatus; the source node apparatus and the destination node apparatus both being in an Internet Protocol/Wavelength Division Multiplexing network; an initial path connecting the source node apparatus to the destination node apparatus; a first router associated with the source node apparatus; a second router associated with the destination node apparatus; and a optical cross-connect associated with the source node apparatus and configured to add and delete at least one additional path between the first and second routers, the first optical cross-connect configured to add and delete the at least one additional path independently and asynchronously of a traffic variation without signaling the destination node apparatus.

Abstract: A bidirectional optical add-drop multiplexer adds and drops optical signals having specific wavelengths among the WDM optical signals transmitted bidirectionally through one of the optical transmission lines connected between neighbor nodes in a bidirectional WDM ring network.

Abstract: A light emitting section outputs an optical signal having an intensity corresponding to a transmission timing signal, the optical signal modulated based on a radio transmission signal. A received photocurrent detection section detects an intensity of an optical signal received by a light receiving section. In accordance with the detected intensity, a high frequency amplification section amplifies the output signal of the light receiving section, and a transmission timing signal reconstruction section reconstructs the transmission timing signal.

Abstract: A frequency-agile optical transceiver includes a shared local oscillator (LO), a coherent optical receiver and an optical transmitter. The LO operates to generate a respective LO optical signal having a predetermined LO wavelength. The coherent optical receiver is operatively coupled to the LO, and uses the LO signal to selectively receive traffic of an arbitrary target channel of an inbound broadband optical signal. The optical transmitter is also operatively coupled to the LO, and uses the LO to generate an outbound optical channel signal having a respective outbound channel wavelength corresponding to the LO wavelength.

Abstract: A wavelength-division multiplexing optical transmission system for providing a compensating-purpose dispersion D2 to a wavelength-division multiplexing optical signal to be transmitted through an optical transmission path from a transmitter terminal to a receiver terminal. The compensating-purpose dispersion D2 satisfies conditions that at any wavelength “?” included in the transmission wavelength band, if dD1(?)/d??0 is established, then {dD1(?)/d?}×{dD2(?)/d?}<0 is also established, and if dD1(?)/d?=0 is established, then dD2(?)/d?=0 is also established, where D1 represents a dispersion generated in the wavelength-division multiplexing optical signal during when the wavelength-division multiplexing optical signal is transmitted through the transmission path from the transmitter terminal to the receiver terminal.