347 research outputs found
Field-trial of an all-optical PSK regenerator/multicaster in a 40 Gbit/s, 38 channel DWDM transmission experiment
No full textThe performance of future ultra-long haul communication systems exploiting phase-encoded signals is likely to be compromised by noise generated during signal transmission. One potential way to mitigate such noise is to use Phase Sensitive Amplifiers (PSAs) which have been demonstrated to help remove phase as well as amplitude noise from phase-encoded signals. Recently, we showed that a PSA-based signal regenerator based on degenerate four-wave mixing can be implemented in a network-compatible manner in which only the (noisy) signal is present at the device input (black-box operation). The developed regenerator was also able to perform simultaneous wavelength conversion and multicasting, details/analysis of which are presented herein. However, this scheme was tested only with artificial noise generated in the laboratory and with the regenerator placed in front of the receiver, rather than in-line where even greater performance benefits are to be expected. Here, we address both theoretically and experimentally the important issue of how such a regenerator, operating for convenience in a multicasting mode, performs as an in-line device in an installed transmission fiber link. We also investigate the dispersion tolerance of the approach
Numerical Analysis of Passively Mode-Locked Quantum-Dot Lasers With Absorber Section at the Low-Reflectivity Output Facet
No full textIn this paper, we present a theoretical study on the optimization of passively mode-locked quantum dot lasers based on an alternative cavity design. In particular, we investigate a geometry in which the saturable absorber is located near the low reflection facet of the chip (output facet). The investigation is carried out by means of a time-domain traveling wave numerical model for quantum-dot active medium for both the gain and absorbing sections. The analysis shows superior performance in terms of pulsewidth and peak power of devices based on the new geometry compared to devices based on the conventional geometry, where the saturable absorber is placed near the high reflectivity facet. The optimization relies on the enhanced bleaching of the saturable absorber when the latter is located near the output facet, which prevents the generation of colliding or self-colliding pulse effect
First demonstration of all-optical QPSK signal regeneration in a novel multi-format phase sensitive amplifier
No full textWe propose a novel black-box optical phase sensitive amplifier (PSA) configuration and describe its application to the regeneration of multi-level phase encoded signals. The concept is demonstrated with a 10 Gbaud quadrature phase shift keyed (QPSK) input
Phase-encoded signal regeneration exploiting phase sensitive amplification
No full textWe discuss recent advances in phase-sensitive amplification technology and review its application to the regeneration of multi-level phase-encoded signals
Phase-encoded signal regeneration exploiting phase sensitive amplification
No full textWe discuss recent advances in phase-sensitive amplification technology and review its application to the regeneration of multi-level phase-encoded signals
Silicon germanium platform enabling mid-infrared to near-infrared conversion for telecom and sensing applications
No full textThis paper presents the potential of silicon germanium waveguides in the nonlinear conversion of light from mid-infrared wavelengths to the telecom band utilizing four-wave mixing. Design aspects and first characterization results of fabricated devices are presented
Linear and nonlinear properties of SiGe waveguides at telecommunication wavelengths
No full textWe report the characterization of the optical properties of Silicon-Germanium (SiGe) waveguides. The evolution of these properties is presented as a function of the Ge concentration and the waveguide width
Experimental investigations on the generation and amplification of high power short pulses by a quantum dot laser and amplifier
No full textIn this paper, we study experimentally the generation of picosecond short optical pulses with an improved peak power of 42 W at a repetition rate of 16 GHz and an associated pulse width of 1.4 ps. Pulses from a tapered quantum dot laser emitting at 1250 nm are amplified using a tapered quantum dot optical amplifier without any pulse post-compression. We specifically investigate the amplification behavior of this master-oscillator power-amplifier configuration with a focus on the pulse peak power, pulse width, average power and amplified spontaneous emission towards improving the figure of merit for two photon excitation microscop
Symmetric few-mode fiber couplers as the key component for broadband mode multiplexing
No full textAll-fiber broadband mode multiplexers (MMUXs) for mode and wavelength division multiplexing transmission systems are designed and analyzed. The MMUXs are based on cascaded 2-D or 3-D symmetric few-mode fiber (FMF) couplers. The MMUXs are optimized for operation over the C band and multiplex modes LP 01 , LP11a, LP11b, LP21a, LP 21b, and LP02with a nearly flat response and an average insertion loss around 1.6 dB, depending on the design approach. The operation of the FMF couplers and the MMUXs is analyzed numerically by means of a full-vectorial beam propagation method. If the two polarization states of each LP mode are further considered, such all-fiber MMUXs can be used to combine 12 spatial channels, supporting an order of magnitude capacity increase-compared to a single spatial channel system-in optical fiber transmission systems through space (mode and polarization) division multiplexing. © 2014 IEEE
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