Static and dynamic characteristics of an InAs/InP quantum-dot optical amplifier operating at high temperatures.

We report on high quality InAs/InP quantum dot optical amplifiers for the 1550 nm wavelength range operating over a wide temperature range of 25 to 100 °C. A temperature dependent shift of the peak gain wavelength at a rate of 0.78 nm/K is observed. Consequently, two possible modes of operation are performed for a systematic device characterization over the entire temperature range. In the first mode, the signal wavelength is tuned to always match the peak gain wavelength while in the second mode, the signal wavelength is kept constant as the gain spectrum shifts with the temperature. Static characteristics, such as gain spectra and saturation levels, as well as dynamical properties, are presented. Distortion-less amplification of a single 28 Gbit/s signal and cross-talk free amplification of two channels, detuned by 2 nm, were demonstrated over the entire temperature range.

Narrowband optical parametric amplification measurements in Ga0.5In0.5P photonic crystal waveguides.

We report the first demonstration of narrowband parametric amplification in a chip scale semiconductor waveguide. A dispersion engineered, Ga0.5In0.5P photonic crystal waveguide with a dispersion function that exhibits two zero crossings was used with a pulsed pump placed in the normal dispersion regime while a tunable probe was scanned on either side of the pump. A peak conversion efficiency of -10 dB was obtained with a peak pump power of only 650 mW. The narrowband nature of the gain spectrum was clearly demonstrated.

Dual-pump parametric amplification in dispersion engineered photonic crystal waveguides.

This paper describes a numerical simulation of narrow band parametric amplification in dispersion engineered photonic crystal waveguides. The waveguides we analyze exhibit group velocity dispersion functions which cross zero twice thereby enabling many interesting pumping schemes. We analyze the case of two pulsed pumps each placed near one of the zero dispersion wavelengths. These configurations are compared to conventional single pump schemes. The two pumps may induce phase matching conditions in the same spectral location enabling to control the gain spectrum. This is used to study the gain and fidelity of 40 G bps NRZ data signals.

Parametric gain in dispersion engineered photonic crystal waveguides.

We present a numerical simulation of parametric gain properties in GaInP PhC dispersion engineered waveguides in which the group velocity dispersion crosses zero twice and where the pump and the signal are 100 ps pulses. The simulations use the M-SSFT algorithm which incorporates dispersive nonlinear coefficients and losses. We concentrate on narrow band parametric gain which occurs for pump wavelengths in the normal group velocity dispersion regime. The effects of structural details, of pump wavelength and of losses are carefully analyzed.

Narrowband optical parametric gain in slow mode engineered GaInP photonic crystal waveguides.

We predict narrowband parametric amplification in dispersion-tailored photonic crystal waveguides made of gallium indium phosphide. We use a full-vectorial model including the dispersive nature both of the nonlinear response and of the propagation losses. An analytical formula for the gain is also derived.

Efficient parametric interactions in a low loss GaInP photonic crystal waveguide.

We describe time domain characterizations of dynamic four-wave mixing in a low loss modified W1 GaInP photonic crystal waveguide. Using 32 ps wide pump pulses with peak powers of up to 1.1 W we achieved a very large conversion efficiency of -6.8 dB as well as a 1.3 dB parametric gain experienced by a weak CW probe signal. Time domain simulations confirm quantitatively all the measured results.

Time domain switching/demultiplexing using four wave mixing in GaInP photonic crystal waveguides.

We describe dynamical four wave mixing (FWM) functionalities of an GaInP photonic crystal waveguide. A W1 waveguide was used to wavelength convert 100 ps pulses and for sampling a 10.56 Gbit/s data stream so as to time demultiplex it into 16 or 32 channels. In all cases, the extracted pulses at the idler wavelength are undistorted and have a high signal to noise ratio proving the high efficiency and the versatility of the FWM process in the GaInP PhC waveguides we used.

Fiber parametric oscillator for the 2 µm wavelength range based on narrowband optical parametric amplification.

We describe a widely tunable synchronously pumped coherent source based on the process of narrowband parametric amplification in a dispersion-shifted fiber. Using an experimental fiber with a zero-dispersion wavelength of 1590 nm and pump wavelengths of 1530 to 1570 nm yields oscillations at 1970 to 2140 nm-the longest reported wavelength for a fiber parametric oscillator. The long-wavelength oscillations are accompanied by simultaneous short-wavelength oscillations at 1200 to 1290 nm. The parametric gain is coupled to stimulated Raman scattering. For parametric oscillations close to the Raman gain peak, the two gain processes must be discriminated from each other. We devised two configurations that achieve this discrimination: one is based on the exploitation of the difference in group delay between the wavelengths where Raman and parametric gain peak, and the other uses intracavity polarization tuning.

Large tunable delay with low distortion of 10 Gbit/s data in a slow light system based on narrow band fiber parametric amplification.

We describe slow light propagation of a 10 Gbit/s data stream in a narrow band fiber parametric amplifier. A large tunable delay of 10 to 60 ps with very low signal distortion has been demonstrated in a 1 km long dispersion shifted fiber. The longitudinal variation of the fiber propagation parameters was extracted from measured amplified spontaneous emission and these parameters serve to accurately predict the delayed temporal pulse shape. Simulated results suggest that the system exhibits large delays with low distortions in a wide spectral range within the OPA gain spectrum.

Expression and characterization of cM-T413, a chimeric anti-CD4 antibody with in vitro immunosuppressive activity.

Anti-CD4 monoclonal antibodies (mAbs) have shown considerable promise in the treatment of rheumatoid arthritis, psoriasis, and allograft rejection and may have potential use in blocking HIV-1 infection. One such anti-CD4 mAb we have developed, chimeric M-T412 (or cM-T412), has been used in clinical trials to treat rheumatoid arthritis, generalized postular psoriasis, and other autoimmune diseases. Here we report the cloning and expression of a second chimeric anti-CD4 mAb using M-T413, a murine mAb that blocks HIV-1 infection of H9 cells. We cloned the immunoglobulin light and heavy chain variable regions of M-T413, combined them with the human kappa (light chain) or G1, G2, G3 and G4 (heavy chain) constant regions in human expression vectors, and expressed these chimeric mAbs in 653 cells. Like chimeric M-T412 IgG1, the chimeric M-T413 mAbs inhibit T-cell proliferation in the mixed lymphocyte response and thus can act to immunosuppress CD4+ T-cell response. In contrast to M-T412, however, the M-T413 chimeric mAbs have reduced activity in an antibody-dependent cell-mediated cytotoxicity (ADCC) assay using human CD4+ target and effector cells. We conclude that the chimeric M-T413 mAbs have potential utility in treating autoimmune disease and may be useful as prophylactics in preventing HIV-1 infection.