Abstract: A swept wavelength light source is provided, the light source includes a semiconductor gain device operable to provide amplification, an optical retarding device, the retarding device having a block of material, a beam path with a well-defined beam path length being defined for light within the block of material produced by the gain device, a wavelength selector, and the gain device, the retarding device and wavelength selector being mutually arranged on the base so that a resonator is established for light portions emitted by the gain device and selected by wavelength selector; this does not exclude the presence of further elements contributing to the resonator, such as additional mirrors (including resonator end mirrors), lenses, polarization selective elements, other passive optical components, etc.; wherein the beam path in the retarding device is a part of a beam path of the resonator.

Abstract: A method and apparatus for accessing and storing data in a memory are disclosed. The system includes a memory controller coupled to a memory having locations characterized by banks and lines. The memory controller is configured for storing a data packet with data bursts in sequence in consecutive memory locations, while providing the capability of reading or writing data bursts out of sequence by accessing the consecutive memory locations in a random order.

Abstract: A method and apparatus for accessing and storing data in a memory are disclosed. The system includes a memory controller coupled to a memory having locations characterized by banks and lines. The memory controller is configured for storing a data packet with data bursts in sequence in consecutive memory locations, while providing the capability of reading or writing data bursts out of sequence by accessing the consecutive memory locations in a random order.

Abstract: In a representative embodiment, a transmitter of a WDM communication system is equipped with a Mach-Zehnder modulator (MZM) configured to produce an optical signal corresponding to a duobinary data stream by modulating a beam of light passing through the MZM. A three-level electrical signal is applied to the MZM to modulate the light. At the second signal level, the modulator substantially blocks light transmission. At the first and third levels, the modulator transmits light corresponding to the duobinary “?1” and “+1” bits, respectively, such that a relative phase shift between the optical bits is different than 180 degrees, i.e., the phase shift value employed in prior-art optical duobinary modulation.

Abstract: A TDM comprising: (a) at least two wavelength-tunable devices for outputting a signal, each wavelength-tunable device being adapted to change signal wavelength in response to a change signal; (b) a plurality of on-off gates, one on-off gate being coupled to the output of each wavelength-tunable device such that, when a gate is on, the signal of its respective wavelength-tunable device passes through, and, when it is off, the signal of its respective wavelength-tunable device does not pass through, the gates being configured such that a gate is switched off when its respective wavelength-tunable device receives a change signal, and, when one gate is turned off, another gate is turned on; and (c) a combiner coupled to the outputs of all the gates for combining the outputs on a single transmission line.

Abstract: Local add traffic exchange between separate East and West line cards in a Half-MAC architecture for Resilient Packet Ring networks is provided by a scheduler and a shared transit path between RPR MACs. By sharing the interconnecting bus that is used for the transit of traffic between the two RPR MACs, a path is provided for the local add traffic that needs to be redirected to the other RPR line card.

Abstract: A timing circuit for a receiver adapted for receiving data packet transmissions, each packet having a particular data frequency, the timing circuit comprising: (a) a clock generating circuit for generating a clock signal derived from a local reference clock signal and not from received data packets; and (b) a phase shifter circuit for synchronizing the phase of the clock signal to that of the particular data frequency

Abstract: A TDM comprising: (a) at least two wavelength-tunable devices for outputting a signal, each wavelength-tunable device being adapted to change signal wavelength in response to a change signal; (b) a plurality of on-off gates, one on-off gate being coupled to the output of each wavelength-tunable device such that, when a gate is on, the signal of its respective wavelength-tunable device passes through, and, when it is off, the signal of its respective wavelength-tunable device does not pass through, the gates being configured such that a gate is switched off when its respective wavelength-tunable device receives a change signal, and, when one gate is turned off, another gate is turned on; and (c) a combiner coupled to the outputs of all the gates for combining the outputs on a single transmission line.

Abstract: In a representative embodiment, a transmitter of a WDM communication system is equipped with a Mach-Zehnder modulator (MZM) configured to produce an optical signal corresponding to a duobinary data stream by modulating a beam of light passing through the MZM. A three-level electrical signal is applied to the MZM to modulate the light. At the second signal level, the modulator substantially blocks light transmission. At the first and third levels, the modulator transmits light corresponding to the duobinary “?1” and “+1” bits, respectively, such that a relative phase shift between the optical bits is different than 180 degrees, i.e., the phase shift value employed in prior-art optical duobinary modulation.

Abstract: A switch employs two or more parallel optical switch fabrics, e.g., arrayed waveguide gratings (AWG), combined with a set of transmitter cards. Each transmitter card has a tunable laser and two or more modulators, each configured to modulate a different copy of the output of the laser with a different set of data. Outputs of the modulators in each transmitter card are coupled to a set of corresponding input ports in the AWGs. A set of receiver cards, each receiver card having the number of receivers matching that of modulators in the transmitter cards, is coupled to output ports of the AWGs, such that each receiver card receives signals from a set of corresponding output ports in the AWGs. Each transmitter card can be configured to send data to any receiver card by setting the wavelength of its laser to the value corresponding to the set of output ports in the AWGs coupled to that receiver card. A parallelized optical switch may be optimized based on a desired set of criteria, e.g.

Abstract: An optical switch configured to reduce packet-to-packet optical power variation corresponding to different switch channels. The optical switch includes a plurality of optical amplifiers coupled to the input or output ports of an optical switch fabric (OSF), e.g., an arrayed waveguide grating. Each amplifier may be a semiconductor optical amplifier configured to operate in the saturated regime. In addition, the maximum output power of each amplifier may be set to a different value related to the insertion loss in the OSF. As a result, at each receiver corresponding to an output port of the OSF, the optical power corresponding to data packets arriving from different input ports may be substantially equalized. Such equalization may reduce the number of bit errors in the switch.

Abstract: A switch employs two or more parallel optical switch fabrics, e.g., arrayed waveguide gratings (AWG), combined with a set of transmitter cards. Each transmitter card has a tunable laser and two or more modulators, each configured to modulate a different copy of the output of the laser with a different set of data. Outputs of the modulators in each transmitter card are coupled to a set of corresponding input ports in the AWGs. A set of receiver cards, each receiver card having the number of receivers matching that of modulators in the transmitter cards, is coupled to output ports of the AWGs, such that each receiver card receives signals from a set of corresponding output ports in the AWGs. Each transmitter card can be configured to send data to any receiver card by setting the wavelength of its laser to the value corresponding to the set of output ports in the AWGs coupled to that receiver card. A parallelized optical switch may be optimized based on a desired set of criteria, e.g.