Abstract: A network element comprising a phase matched or phase controlled interconnect configured to receive a data signal sample, a Raman equalization transmitter, and a Raman crosstalk equalization conditioning circuit configured to generate a Raman mitigation signal using the data signal sample to be transmitted by the Raman equalization transmitter. Included is a method comprising multiplexing incoherent data signals with a video signal and a Raman mitigation signal to be co-propagated on a single optical fiber, wherein the Raman mitigation signal is selected to destructively interfere with Raman crosstalk noise induced on the video signal. Also included is a system comprising a video signal component configured to transmit a video signal, data stream signal components configured to transmit a data stream signals, a Raman crosstalk equalization system configured to transmit a Raman mitigation signal, and an optical multiplexer configured to multiplex the signals for co-propagation onto a single transmission fiber.

Abstract: A burst mode laser transmitter includes a burst mode laser diode and a controller having an input for receiving an RF data signal. The controller includes a triggering arrangement and a modulation arrangement. The triggering arrangement is configured to bias the laser diode to an on-state bias level when an RF data signal is present at the input to the controller and to an off-state bias level when no RF data signal is present at the input to the controller. The modulation arrangement is configured to modulate the on-state bias level at which the laser diode is biased with the RF data signal only when the RF data signal is present at the input of the controller.

Abstract: A system includes an optical transmitter portion, an optical fiber, an optical receiver portion, a laser portion and a combiner portion. Optical signals may be launched by the optical transmitter portion at very low power levels to avoid Raman-induced interactions between the co-propagating signals along the optical fiber. The laser portion and the combiner portion may apply a back-pumped laser signal to the optical fiber. The back-pumped laser signal provides a Raman gain that amplifies the co-propagating signals to a minimum power level such that the optical receiver portion can detect the co-propagating signals within a predetermined acceptable carrier-to-noise ratio.

Abstract: A method and apparatus is provided for transmitting a WDM optical signal. The method begins by modulating an odd number of optical channels that are each located at a different wavelength from one another with (1) a respective one of a plurality of information-bearing electrical signals that all embody the same broadcast information and (2) a respective one of a plurality of RF signals having a common functional broadcast waveform, at least one of the RF signals being out of phase with respect to remaining ones of the plurality of RF signals. Each of the modulated optical channels are multiplexed to form a WDM optical signal. The WDM optical signal is forwarded onto an optical transmission path.

Abstract: A system includes an optical transmitter portion, an optical fiber, an optical receiver portion, a laser portion and a combiner portion. Optical signals may be launched by the optical transmitter portion at very low power levels to avoid Raman-induced interactions between the co-propagating signals along the optical fiber. The laser portion and the combiner portion may apply a back-pumped laser signal to the optical fiber. The back-pumped laser signal provides a Raman gain that amplifies the co-propagating signals to a minimum power level such that the optical receiver portion can detect the co-propagating signals within a predetermined acceptable carrier-to-noise ratio.

Abstract: A burst mode laser transmitter includes a burst mode laser diode and a controller having an input for receiving an RF data signal. The controller includes a triggering arrangement and a modulation arrangement. The triggering arrangement is configured to bias the laser diode to an on-state bias level when an RF data signal is present at the input to the controller and to an off-state bias level when no RF data signal is present at the input to the controller. The modulation arrangement is configured to modulate the on-state bias level at which the laser diode is biased with the RF data signal only when the RF data signal is present at the input of the controller.

Abstract: A method and apparatus is provided for transmitting a WDM optical signal. The method begins by modulating an odd number of optical channels that are each located at a different wavelength from one another with (1) a respective one of a plurality of information-bearing electrical signals that all embody the same broadcast information and (2) a respective one of a plurality of RF signals having a common functional broadcast waveform, at least one of the RF signals being out of phase with respect to remaining ones of the plurality of RF signals. Each of the modulated optical channels are multiplexed to form a WDM optical signal. The WDM optical signal is forwarded onto an optical transmission path.

Abstract: An optical spread spectrum communication system includes a tunable laser which sequentially outputs optical signals having different wavelengths. The laser produces a frequency spectrum having a plurality of closely spaced modes relative to optical frequencies. The system further includes an optical modulator and a frequency synthesizer. The frequency synthesizer controls the optical modulator to allow specific modes from the frequency spectrum to pass through. Additionally, the system includes a tunable filter and a phase locked loop (PLL) control circuit. The PLL control circuit controls the filter to select specific channels. The selection of the specific modes by the modulator and the selection of channels by the tunable filter are performed independent of each other and are based on randomly assigned codes generated in accordance with one or more algorithms.

Abstract: An optical frequency synthesizer controls a tunable laser to output signals having specific wavelengths. The synthesizer includes a wavelength discriminating device, a wavelength tuning device and a phase locked loop (PLL) circuit. The wavelength discriminating device receives a sample of the signals outputted by the tunable laser, processes the sample signals and passes the processed sample signals to the PLL circuit. Based on the processed sample signals, the PLL circuit controls the wavelength tuning device to tune the laser to output the signals having specific wavelengths.

Abstract: An optical spread spectrum communication system includes a tunable laser which sequentially outputs optical signals having different wavelengths. The laser produces a frequency spectrum having a plurality of closely spaced modes relative to optical frequencies. The system further includes an optical modulator and a frequency synthesizer. The frequency synthesizer controls the optical modulator to allow specific modes from the frequency spectrum to pass through. Additionally, the system includes a tunable filter and a phase locked loop (PLL) control circuit. The PLL control circuit controls the filter to select specific channels. The selection of the specific modes by the modulator and the selection of channels by the tunable filter are performed independent of each other and are based on randomly assigned codes generated in accordance with one or more algorithms.

Abstract: An all-optical reference clock used to generate a stable radio frequency (RF) comb spectrum. The all-optical reference clock includes a fiber ring laser, a tunable mode selection filter and one or more phase locked loop (PLL) control circuits. The fiber ring laser has an effective loop circumference which produces a fundamental frequency mode spacing fl. The all-optical reference clock is configured to output a plurality of equally spaced frequencies which include a frequency fo and the harmonics thereof. The PLL control circuit receives a sample of the spaced frequencies and adjusts the tunable mode selection filter to maintain the desired spacing between the spaced frequencies. In one embodiment, a line-stretching drum, having a variable diameter and controlled by the PLL control circuit, is used to tune the mode selection filter. In another embodiment, a voltage controlled oscillator (VCO) controls a Mach-Zehnder modulator to eliminate undesired frequencies.

Abstract: A fully “time tunable” all-optical switch routes/switches digital bits (packets) in an all-optical format for transmission, or for further processing, in an all-optical communication network. The all-optical switch is implemented in either a semiconductor hybrid or in a completely monolithic form. Variable time delay elements adjust the time delay of a clocking signal input and a data packet input. The clocking signal determines the state of two nonlinear optical elements, such as semiconductor optical amplifiers, incorporated in the upper and lower arms of a Mach-Zehnder configuration. An optical coupler is connected to the output of the all-optical switch. The output of data from selected ports of the optical coupler is controlled using the variable time delay elements.

Abstract: An optical device which monolithically integrates a variety of structures to route or demultiplex data. One or more ring resonators are used to couple a control signal into and out of a waveguide loop residing within the optical device. The device includes a waveguide loop interferometer, such as a Sagnac loop, and a nonlinear element, such as a semiconductor optical amplifier, inserted in the loop. A ring resonator removes the control signal from the waveguide loop after it passes through the nonlinear element. The control signal is removed via a path that is independent of paths used for managing the flow of data through the optical device. Data is selectively outputted from one of two output ports, depending upon the state of the nonlinear device, as determined by the control signal.

Abstract: An optical device which monolithically integrates a variety of structures to route or demultiplex data. One or more ring resonators are used to couple a control signal into and out of a waveguide loop residing within the optical device. The device includes a waveguide loop interferometer, such as a Sagnac loop, and a nonlinear element, such as a semiconductor optical amplifier, inserted in the loop. A ring resonator removes the control signal from the waveguide loop after it passes through the nonlinear element. The control signal is removed via a path that is independent of paths used for managing the flow of data through the optical device. Data is selectively outputted from one of two output ports, depending upon the state of the nonlinear device, as determined by the control signal.

Abstract: A fully “time tunable” all-optical demultiplexer selects which digital bits or groups of bits in an all-optical data packet or all-optical data burst are to be read/demultiplexed. The all-optical demultiplexer is implemented in either a semiconductor hybrid or in a completely monolithic form. The all-optical demultiplexer is formatted in either a “normally on” or “normally off” configuration. Variable time delay elements adjust the time delay of a clocking signal input and a data packet input. The clocking signal determines the state of two nonlinear optical elements, such as semiconductor optical amplifiers, incorporated in the upper and lower arms of a Mach-Zehnder configuration. Only desirable digital bits or groups of bits are outputted from the demultiplexer. All other undesirable bits are suppressed.

Abstract: A fully “time tunable” all-optical demultiplexer selects which digital bits or groups of bits in an all-optical data packet or all-optical data burst are to be read/demultiplexed. The all-optical demultiplexer is implemented in either a semiconductor hybrid or in a completely monolithic form. The all-optical demultiplexer is formatted in either a “normally on” or “normally off” configuration. Variable time delay elements adjust the time delay of a clocking signal input and a data packet input. The clocking signal determines the state of two nonlinear optical elements, such as semiconductor optical amplifiers, incorporated in the upper and lower arms of a Mach-Zehnder configuration. Only desirable digital bits or groups of bits are outputted from the demultiplexer. All other undesirable bits are suppressed.

Abstract: High quality epitaxial layers of compound semiconductor materials can be grown overlying large silicon wafers by first growing an accommodating buffer layer on a silicon wafer. An accommodating buffer layer comprises a layer of monocrystalline oxide spaced apart from a silicon wafer by an amorphous interface layer of silicon oxide. The amorphous interface layer dissipates strain and permits the growth of a high quality monocrystalline oxide accommodating buffer layer. The accommodating buffer layer is lattice matched to both the underlying silicon wafer and the overlying monocrystalline compound semiconductor layer. Any lattice mismatch between the accommodating buffer layer and the underlying silicon substrate is taken care of by the amorphous interface layer. A composite integrated circuit having a tunable laser is provided. The laser may be mode-locked. Injection-locking may be used to pass optical properties to a slave laser.

Abstract: Composite optical modulation semiconductor structures and methods are provided that are useful for optical communication systems, for example, for modulating user signals in CDMA systems. DBR lasers, waveguides, Bragg gratings, and modulators/encoders are shown that are fabricated within compound semiconductor layers or accommodating layers of a composite semiconductor structure. The composite semiconductor structure is supported by a non-compound semiconductor substrate, that increases manufacturing yields of composite semiconductor structures. Modulating methods shown include electro-optic modulation, piezo-electric modulation, and current injection modulation.

Abstract: High quality epitaxial layers of monocrystalline materials can be grown overlying monocrystalline substrates such as large silicon wafers by forming a compliant substrate for growing the monocrystalline layers. An accommodating buffer layer comprises a layer of monocrystalline oxide spaced apart from a silicon wafer by an amorphous interface layer of silicon oxide. The amorphous interface layer dissipates strain and permits the growth of a high quality monocrystalline oxide accommodating buffer layer. The accommodating buffer layer is lattice matched to both the underlying silicon wafer and the overlying monocrystalline material layer. Any lattice mismatch between the accommodating buffer layer and the underlying silicon substrate is taken care of by the amorphous interface layer. In addition, formation of a compliant substrate may include utilizing surfactant enhanced epitaxy, epitaxial growth of single crystal silicon onto single crystal oxide, and epitaxial growth of Zintl phase materials.

Abstract: High quality epitaxial layers of monocrystalline materials can be grown overlying monocrystalline substrates by forming a compliant substrate for growing the monocrystalline layers. An accommodating buffer layer comprises a layer of monocrystalline oxide spaced apart from a silicon wafer by an amorphous interface layer of silicon oxide. The amorphous interface layer dissipates strain and permits the growth of a high quality monocrystalline oxide accommodating buffer layer. In this way, optical waveguides can be fabricated along with integral silicon-based circuitry to provide an optical device in an efficient, low-cost semiconductor structure. Moreover, control circuits can be added to change the dielectric property of the monocrystalline materials thereby affecting optical signals therein.