Recent developments in fiber optic devices

Recent developments in the fiber-optic communication technologies are reviewed with emphasis on the fundamental transverse mode laser diode and low-loss quartz optical fiber. The fundamental transverse mode has been realized both with short-wavelength AlGaAs (0.8-0.9 micron) and long-wavelength (1.2-1.6 microns) InGaAsP lasers. Lasing mode and laser structure, wavelength and output, modulation, noise and stability, module and coupling, and also characteristics of light emitting diodes and detectors are examined. Methods for making preform of quartz fiber, including the modified chemical vapor deposition method and VAD method are discussed along with the adhesive butt joint and fusion splicing techniques.