The technique of velocity modulation spectroscopy has recently been combined with cavity enhancement and frequency modulation methods into a technique called noise-immune cavity-enhanced optical heterodyne velocity modulation spectroscopy (NICE-OHVMS). We have implemented NICE-OHVMS with a cw-optical parametric oscillator (OPO) tunable from 3.2 to 3.9 lm, and used it to record spectra of the R(...

We propose optical path routing and frequency slot assignment algorithms that can make the best use of elastic optical paths and the capabilities of distance adaptive modulation. Due to the computational difficulty of the assignment problem, we develop algorithms for 1+1 dedicated/1:1 shared protected ring networks and unprotected mesh networks to that fully utilize the characteristics of the t...

Abstract – Free Space Optical (FSO) communication technology becomes a promising solution for the future optical broadband networks. This work is focused to carry out the investigation of the performance of Orthogonal Frequency Division Multiplexing (OFDM) FSO system using Optical Single Sideband (OSSB), Optical Double Sideband (ODSB) and Optical Vestigial Sideband (OVSB) modulation scheme by e...

For optical communication links using wavelength-division multiplexing over a long-haul fiber optic backbone, stimulated raman scattering may lead to significant transmission impairment. This paper discusses the enhanced analysis for the SRS induced crosstalk in the optical networks. The expression for Stimulated Raman Scattering induced crosstalk have been observed at different fiber types( as...

With the growing popularity of social media services, e-commerce, and many other internet-based services, we are witnessing a rapid growth in the deployment of data centers and cloud computing platforms. As a result, the telecommunications industry has to continue providing additional network capacity to meet the increasing demand for bandwidth. The use of fiber-optic communications plays a key...

One of the foremost applications of VCSELs is to transmit optical signals. These signals require modulation of the VCSEL to vary its emitted power. This note provides information about VCSEL modulation that may assist in the design of optical transmitters. While many of the same principles apply to analog modulation applications, this note is aimed primarily at digital applications where data i...

We report the optical injection modulation of semiconductor lasers by intra-cavity stimulated Raman scattering. This mechanism manifests itself as sharply enhanced modulation bandwidth in InAs/InGaAlAs/InP quantum-dash lasers when the injected photons are 33 +/- 3 meV more energetic than the lasing photons. Raman scattering measurements on the quantum-dash structure and rate equation models str...

Modulation instability is thoroughly investigated and a simple analytical model for its power critically modifying the wave properties in terms of system parameters is derived and experimentally validated. The differences on the modulation instability gain spectrum in lossless and lossy optical fibers are analyzed based on theoretical models and numerical simulations. In particular the impact o...

This paper describes the need of knowing fiber non-linear coefficient in global optical networks. The basic Kerr non-linearities that appear in silica-based optical fibers have been summarized, together with their implications for optical communication systems. In this paper, the non-linear coefficient has been discussed and its measurement techniques reviewed. The brief description of each met...

We have studied the long term variability of LMC X-3 in optical lightcurves spanning six years, in order to search for optical signatures which could confirm/refute the suggestion that the ‘modulation’ is the result of accretion rate variability rather than accretion disc precession. We find that there is no stable period in the optical lightcurves, that the optical and X-ray lightcurves are co...