Abstract: A method of optically equalizing a multi-level (amplitude or phase) optical signal through the effect of an optical equalizer wherein the optical equalizer (OEQ) is placed at either a transmission end or a receiver end of the optical communications link and a tap delay characteristic of the OEQ need not be determined by symbol spacing, rather it may advantageously be adjusted to desirably compensate non-linear mapping performed in the modulation process or simultaneous operation on a plurality of wavelength division multiplexed (WDM) channels.

Abstract: A driving circuit and Mach-Zehnder EAM optical modulator exhibiting negligible chirp that generates a PSK signal when driven by a single drive signal. Two such Mach-Zehnder EAM optical modulators and drive circuits may be configured in parallel, thereby generating DQPSK signals with only two drive signals, one for each individual Mach-Zehnder EAM modulator.

Abstract: A dispersion compensation apparatus employing an arrayed-waveguide-grating (AWG) which exhibits a dispersion slope.

Abstract: Duobinary and NRZ modulation of an X-Gb/s optical signal is achieved with a lumped element InP Mach-Zehnder device configured to operate at X/k-Gb/s where k>1 and arranged in a push-pull configuration.

Abstract: A low-ripple optical device comprising an optical demultiplexer structure and an optical multiplexer structure cascaded together wherein one of the structures exhibits n passband maxima and the other device exhibits n+1 passband maxima.

Abstract: A high-speed optical modulator constructed from a number of lower speed intensity modulators integrated onto a single optical chip.

Abstract: A polarization-diverse optical amplifier includes a polarization-sensitive optically active medium and a polarization splitter. The polarization splitter is configured to receive input light, to direct a first polarization component of the received input light to a first optical path segment, and to direct a second polarization component of the received input light to a separate second optical path segment. The active medium has first and second optical ports. The first optical port is at an end of the first optical path segment. The second port is at an end of the second optical path segment. The active medium outputs amplified light from one of the ports in response to receiving the input light at the other of the ports. In a preferred embodiment, the active medium has an internal optical axis, and the polarizations of the first and second components are oriented relative to that axis so that amplification is enhanced. The two optical path segments may include polarization-maintaining optical waveguides.

Abstract: A colorless tunable optical dispersion compensator (TODC) comprising a silica arrayed-waveguide grating (AWG) directly coupled to a polymer thermo-optic lens. As a result of its inventive construction, the device exhibits low loss, large tuning range, low electrical consumption and is readily manufactured using standard processes. Additionally, the TODC is fully solid-state and scales to a large figure-of-merit (dispersion range times bandwidth squared).

Abstract: A WDM communication system having two optical-frequency comb sources (OFCSs) that are substantially phase-locked to one another, with one of these OFCSs used at a transmitter to produce a WDM communication signal and the other OFCS used at a receiver to produce multiple local-oscillator signals suitable for homodyne detection of the WDM communication signal received from the transmitter. In one embodiment, the transmitter has (i) a first OFCS adapted to generate a first frequency comb and (ii) an optical modulator adapted to use the first frequency comb to generate a WDM communication signal for transmission to the receiver, this WDM signal having at least two beacon lines. The receiver has a second OFCS adapted to produce a second frequency comb such that the second frequency comb has at least two comb lines having the beacon frequencies, the phases of which comb lines are locked to the phases of the beacon lines of the received WDM signal.

Abstract: An apparatus and method are provided for manipulating light beams propagated through an optical apparatus that includes a planar lightwave circuit (PLC) and free-space optics unit. A multi-wave optical signal coupled to the PLC is propagated through a first and second waveguide array to generate a phased array output at an edge facet of the PLC. The phased array output at the edge facet is spatially Fourier transformed by the lens to generate a spectrally resolved image having a discrete light spot for each channel of the input optical signal, which is coupled to a pixelated optical receiving unit. When the optical receiving unit is a reflector, one or more of the discrete light spot are reflected to a desired waveguide array of a PLC to produce a desired output. When the optical receiving unit is a pixelated transmissive modulator, one or more of the discrete light spot are modulated as they pass through the modulator.

Abstract: A mode-locked laser that has an optical cavity containing multiple optical amplifiers, each dedicated to a respective spectral portion of an optical signal generated by the laser, wherein the dispersion effects are managed by utilizing a separate intra-cavity phase tuner for each such spectral portion and/or by having appropriately configured waveguides corresponding to different spectral portions. Advantageously, a relatively wide combined gain spectrum provided by the optical amplifiers and the intra-cavity dispersion compensation provided by the phase tuners and/or waveguides enable this laser to realize a mode-locking regime that results in the emission of an optical pulse train having a relatively wide frequency spectrum.

Abstract: An improved waveguide structure employing blocks of waveguide core material positioned sufficiently close to a waveguide core thereby eliminating strain effects and its resulting undesirable polarization crosstalk. The improved structures are applicable to a variety of optical components including bent waveguides, directional and star couplers.

Abstract: A dispersion compensation apparatus providing both coarse and fine dispersion compensation employing a pair of slab waveguides, a grating interconnecting the two waveguides, a mirror disposed within the second slab waveguide and one or more thermooptic lense(s), positioned between the mirror and the grating.

Abstract: A proposed integrateable optical interleaver includes an input Y-branch coupler and at least two multi-section optical couplers. The multi-section optical couplers of the interleaver include at least three substantially similar optical couplers, adjacent ones of the optical couplers interconnected via at least one set of waveguides. The interleaver of the present invention comprises a highly compact and fabrication-robust form that is capable of being integrated onto a single planar lightwave circuit.

Abstract: A low-loss rectangular-passband multiplexer including a three-arm interferometer coherently connected to a waveguide grating router (WGR), resulting in a passband substantially of type N=3, without intrinsic loss. The three-arm interferometer has a free-spectral range (FSR) substantially equal to the channel spacing and is connected to an M-arm interferometer having a much larger FSR. The three-arm interferometer includes three waveguides each exhibiting a linearly increasing path length optically connected to a 1×3 coupler and a 3×3 coupler. The 1×3 coupler may be constructed from a series of Y-branch couplers.

Abstract: A fully integrated microelectromechanical (MEMS) 1×K wavelength selective switch (WSS) includes an array of N solid-immersion micromirrors (SIMs) and a K+1 dispersion waveguide arrays that are integrally fabricated together. In one embodiment, the WSS is fabricated in Silicon. In another embodiment, the N actuators of the SIMs are etched in the Silicon layer of a Silicon-on Insulator (SOI) wafer. Thereafter, a Silica layer is deposited on the Silicon layer and the K+1 waveguide arrays and the mirrors for the N SIMs are etched in that Silica layer.

Abstract: A reconfigurable optical add/drop multiplexer (ROADM) includes a first optical dynamic gain equalization filter (DGEF) having a first input for receiving an initial wavelength division multiplexed (WDM) signal, a first output for sending a phase shifted WDM signal, and a second output connected to a demultiplexer for demultiplexing a WDM drop signal thereby producing a plurality of drop channels. A second DGEF having a first input for receiving the phase shifted WDM signal, a second input connected to a multiplexer, for multiplexing a plurality of add channels to produce thereby a wavelength division multiplexed (WDM) add signal, and an output for sending a second adjusted WDM signal. The ROADM allows for the channels from the initial WDM signal to be dropped, added and equalized.

Abstract: An orthogonal heterodyne in-band optical signal-to-noise-ratio (OSNR) monitoring method and apparatus that use the polarization characteristics of two narrow bandwidth filtered optical spectral components which is not only insensitive to the effects of polarization mode dispersion (PMD) and inter-channel cross-phase modulation (XPM) induced nonlinear polarization scattering, but also independent of bit rate and modulation format. The monitoring method is demonstrated for both linear and nonlinear systems.

Abstract: Dispersion compensator apparatus comprising 1XM, MXN and NXN couplers, where the coupling ratios of the MXN and NXN couplers are selected such that the dispersion compensator provides a desired amount of dispersion compensation.

Abstract: A planar lightwave circuit coupler including first and second waveguides with curved coupling portions having radii of curvature selected such that the coupler has a splitting ratio that is substantially wavelength and polarization insensitive.