Telecommunication machines and apparatus, namely, optical transmitters and optical receivers; digital coherent transceivers, optical modulators, integrated optical circuits and semi-conductor chips, optical amplifiers, optical couplers, optical switches, optical gratings, optical drivers; laser chips, pump and signal combiners, pump lasers, interferometers, fiber laser mirror gratings, fiber Bragg gratings, cladding power strippers, frequency taps and splitters, photo detectors, optical isola...