Polarization sensors and controllers for coherent optical communication systems

In this invited tutorial review paper, I discuss the various options available to match the state of polarization of the signal and local oscillator waves in a coherent fiber optical communication system. The various advantages and disadvantages of each technique are discussed and directions for further work are identified. © 1987 SPIE

Single-mode fiber measurements

In this invited tutorial review paper on single-mode fiber measurements, I discuss the various methods used to characterize the following important transmission parameters of single-mode fibers: Attenuation, cut-off wavelength, mode-field diameter and chromatic dispersion. Single-mode fibers are being used increasingly in long-haul links and are even being considered for subscriber networks. © 1986 SPIE

Erbium-Doped Fiber Power Amplifiers with Pump Reflecting Mirrors in the 800 nm Band

The behavior of alumino-phosphate-silicate (APS) erbium-doped fiber power amplifiers (EDFA) for the various pump wavelengths, in the small signal and large signal regime, has been well studied with the 800 nm band pumping. It has already been shown that bidirectional pumping is more efficient especially at shorter wavelengths due to the presence of large excited state absorption (ESA). However, bidirectional pumping requires more components which can increase the complexity and cost of the system. In this letter, we have compared, using a computer model, the performance of power EDFA’s with a Bragg reflecting pump mirror etched at the output end of the fiber. For small pump powers (Pp≈ 10 mW) this configuration is better than bidirectional pumping, both for gain and noise figure (NF). At large pump powers (Pp≈200 mW) the output signal powers are comparable and the noise figure is better for the configuration with the reflecting mirror. © 1992 IEE

Polarization diversity and scrambling techniques for coherent systems

In this paper, we review polarization-diversity and polarization scrambling techniques and also include recent progress in these areas. The advantages and disadvantages of these techniques and several experimental and theoretical results reported to date are also discussed. © 1990 SPIE

Comparison of Forward and Bidirectional Pumping at 805 and 819 nm in Erbium-Doped Silica Fiber Amplifiers

Using an accurate and comprehensive computer model, we compare 805–810 and 819–825 nm band pumping of erbium-doped aluminosilicate fiber amplifiers. A comparison is made for both forward and bidirectional pumping over a wide range of pump powers. It is shown that 805–810 nm pumping is more efficient if bidirectional pumping is used, while 819–825 nm pumping is more efficient if only forward pumping is carried out. © 1991 IEE

Launching Light From Semiconductor Lasers Into Plane-ended Multimode Optical Fibers.

A systematic and detailed study of launching light from semiconductor lasers into plane-ended multimode optical fibers has been carried out--we believe for the first time. Three different semiconductor lasers and four multimode fibers having numerical apertures in the 0.16-0.40 range were used. Simple theoretical models developed for the launching efficiency eta give good agreement with experimental results. We show how erroneous results can be obtained when considering only the stimulated emission of the lasers in calculating eta. The dependence of eta on axial, lateral, and angular misalignments is also investigated and explained qualitatively with ray optics.222337-4

Refractive Index and Material Dispersion Interpolation of Doped Silica in the 0.6-1.8 µm Wavelength Region

In this paper, we propose an extension of the Claussius- Mossotti interpolation scheme, so that the refractive index and material dispersion of GeO2 and F-doped silica glasses, with doping concentrations different than that of published data, can be predicted in the 0.6-1.8 µm wavelength region. The new interpolation expression provides a well-behaved functional relationship for use in computer models which analyze propagation in single-mode fibers. The technique proposed is particularly powerful because it can be applied to any glass, whether single or multicomponent, having any other single dopant. © 1989 IEE