International Telemetering Conference Proceedings / October 26-29, 1992 / Town and Country Hotel and Convention Center, San Diego, California / This paper presents a simple, cost-effective solution that permits the antenna in a telemetry/tracking system to be placed at distances even greater than 20 km with virtually no signal degradation. By using a wideband, microwave fiberoptic link to pass the RF telemetry and tracking signals directly, the telemetry receivers can all be installed at the operator's location. In essence, the only RF equipment that needs to be installed at the antenna site is the low maintenance fiberoptic transmitter which can be placed in a ruggedized housing at the pedestal. The actual system described herein uses a hybrid approach with some telemetry receivers at the antenna site and some remoted over the fiberoptic link. It is shown that the fiberoptic link used met and exceeded the system requirements. In addition, the design of the fiberoptic link is discussed and it is shown that the dynamic range acheivable with this fiberoptic link is considerably higher than the system requirements in this case.

The objective of this thesis work is to increase the functionality of optical fibers for possible applications in life-sciences. Optical fibers are a promising technology for use in biology and medicine. They are low-costwaveguides, flexible and have a small cross-section. They can guide high-power light with low loss in a micrometer core-size. These features make fibers attractive for minimally-invasive,in-vivostudies. The backwards guidance of the optical signal allows for real-time monitoring of the distance to the scattering targets and to study the environment through Raman scattering and fluorescence excitation. The longitudinal holes introduced in the fibers can be used,for instance,for delivery of medicine to a specific regionof a body. They could even be used for the extractionof species considered interesting for further analysis, for example, studyingcells that may be cancer-related. This thesis deals with four main topics. First, a demonstration is presented of the combination of high-power light guidance for ablation, low-power light reflectometry for positioning, and for liquid retrieval in a single fiber. It was found that in order to exploit the microfluidic possibilities available in optical fibers with holes, one needs to be able to combine fluids and light in a fiber without hindering the low-loss light guidance and the fluid flow. Secondly, one should also be able to couple light into the liquids and backout again. This is the subject of another paper in the present thesis. It was also observed that laser excitation through a fiber for the collection of a low-intensity fluorescence signal was often affected by the luminescence noise createdby the primary-coating of the fiber. This problem makes it difficult to measure low light-levels, for example, from single-cells. Athirdpaper in this thesis then describes a novel approach to reduce the luminescence from the polymer coating of the fiber, with the use of a nanometer-thick carbon layer on the cladding surface. Finally, exploiting some of the results described earlier, an optical fiber with longitudinal holes is used for the excitation, identification and for the collection of particles considered being of interest. The excitation light is guided in the fiber, the identification is performed by choosing the fluorescent particles with the appropriate wavelength, and, when a particle of interest is sufficiently near the fiber-tip, the suction system is activated for collection of the particle with good specificity. It is believed that the work described in this thesis could open the doors for applications in life-sciences and the future use of optical fibers for in-vivo studies. / <p>QC 20140516</p>

In 1920, Leon Brillouin discovered a new kind of light scattering – Brillouin scattering – which occurs as a result of the interaction of light with a transparent material’s temporal periodic variations in density and refractive index. Many advances have since been made in the study of Brillouin scattering, in particular in the field of fiber optics. An in-depth investigation of Brillouin scattering in optical fibers has been carried out in this thesis, and the theory of stimulated Brillouin scattering (SBS) and combined Brillouin gain and loss has been extended. Additionally, several important applications of SBS have been found and applied to current technologies. Several mathematical models of the pump-probe interaction undergoing SBS in the steady-state regime have emerged in recent years. Attempts have been made to find analytical solutions of this system of equations, however, previously obtained solutions are numerical with analytical portions and, therefore, qualify as hybrid solutions. Though the analytical portions provide useful information about intensity distributions along the fiber, they fall short of describing the spectral characteristics of the Brillouin amplification and the lack of analytical expressions for Brillouin spectra substantially limits the utility of the hybrid solutions for applications in spectral measurement techniques. In this thesis, a highly accurate, fully analytic solution for the pump wave and the Stokes wave in Brillouin amplification in optical fibers is given. It is experimentally confirmed that the reported analytic solution can account for spectral distortion and pump depletion in the parameter space that is relevant to Brillouin fiber sensor applications. The analytic solution provides a valid characterization of Brillouin amplification in both the low and high nonlinearity regime, for short fiber lengths. Additionally, a 3D parametric model of Brillouin amplification is proposed, which reflects the effects of input pump and Stokes powers on the level of pump wave depletion in the fiber, and acts as a classification tool to describe the level of similarity between various Brillouin amplification processes in optical fibers. At present, there exists a multitude of electro-optic modulators (EOM), which are used to modulate the amplitude, frequency, phase and polarization of a beam of light. Among these modulators, phase modulation provides the highest quality of transmitted signal. As such, an improved method of phase-modulation, based on the principles of stimulated Brillouin scattering, as well as an optical phase-modulator and optical phase network employing the same, has been developed. Due to its robustness, low threshold power, narrow spectrum and simplicity of operation, stimulated Brillouin scattering (SBS) has become a favourable underlying mechanism in fiber-based devices used for both sensing and telecommunication applications. Since birefringence is a detrimental effect for both, it is important to devise a comprehensive characterization of the SBS process in the presence of birefringence in an optical fiber. In this thesis, the most general model of elliptical birefringence in an optical fiber has been developed for a steady-state and transient stimulated Brillouin scattering (SBS) interaction, as well as the combined Brillouin gain and loss regime. The impact of the elliptical birefringence is to induce a Brillouin frequency shift and distort the Brillouin spectrum – which varies with different light polarizations and pulse widths. The model investigates the effects of birefringence and the corresponding evolution of spectral distortion effects along the fiber, and proposes regimes that are more favourable for sensing applications related to SBS – providing a valuable prediction tool for distributed sensing applications. In recent years, photonic computing has received considerable attention due to its numerous applications, such as high-speed optical signal processing, which would yield much faster computing times and higher bandwidths. For this reason, optical logic has been the focus of many research efforts and several schemes to improve conventional logic gates have been proposed. In view of this, a combined Brillouin gain and loss process has been proposed in a polarization maintaining optical fiber to realize all-Optical NAND/NOT/AND/OR logic gates in the frequency domain. A model describing the interaction of a Stokes, anti-Stokes and a pump wave, and two acoustic waves inside a fiber, ranging in length from 350m-2300m, was used to theoretically model the gates. Through the optimization of the pump depletion and gain saturation in the combined gain and loss process, switching contrasts of 20-83% have been simulated for different configurations.