one of a group of cells that develop in the walls of the seminiferous tubules. Spermatogenic cells include spermatogonia, spermatocytes, and spermatidsâall of which are transitional forms between primary sexual cells and spermatozoa.
long-haul optics. Long-haul optics refers to the transmission of visible light signals over optical fiber cable for great distances, especially without or with minimal use of repeaters. Normally, repeaters are necessary at intervals in a length of fiber optic cable to keep the signal quality from deteriorating to the point of non-usability. In long-haul optical systems, the goal is to minimize the number of repeaters per unit distance, and ideally, to render repeaters unnecessary.
Follow. An optical fiber (or optical fibre) is a flexible, transparent fiber made of high quality extruded glass (silica) or plastic, slightly thicker than a human hair. It can function as a waveguide, or âlight pipeâ, to transmit light between the two ends of the fiber. 9. 2  Special-purpose fiber â¢ Some special-purpose optical fiber is constructed with a non-cylindrical core and/or cladding layer, usually with an elliptical or rectangular cross-section. â¢ 3  These include polarization-maintaining fiber and fiber designed to suppress whispering gallery mode propagation.