Pulse Compressor based on Tunable Etched PM-MZI underwater Communication System

Abstract

Underwater Optical Communication System (UOWC) has been used nowadays in modern optical communication systems. It has many militaries, industry, and scientific community applications. A compressed laser source was obtained in this experiment after using a pulse duration of 9 ns, peak power of 1.2297 mW, full width half maximum (FWHM) 286 pm, and a wavelength of 1546.7 nm. This work used three designs Single, cascaded, and nested, designed based on polarization-maintaining Mach-Zander interferometer (PM-MZI) this fiber etched. All three designs are tested in two different ways. The first structure consists of three variable lengths of (PMF) (8, 16, and 24) cm with etching 30 min. The Second structure has three constants of (PMF) 10 cm lengths with different etching times (10, 20, and 30) min correspond to (112.3, 86.7, 72.8) μm cladding diameter respectively. Four samples of water (seawater, shallow water, coastal water, distilled water) are regarded. This paper studies the effect of the four water samples placed on the fibers used in two structures within different three designs. The results obtained were single fiber, the compression factor FC = 1.1 when the PMF length is 24 cm and thickness cladding is 72.8 μm under shallow water. The peak power is (0.11) PW, the central wavelength is 1546.427 nm, and FWHM is 256 pm. while the cascaded shows FC = (1.5) in distilled water with variable fiber lengths. Finally, in design nested, FC is (1.2) in shallow water with constant fiber lengths.