Prototype of a fiber-optical communication system with a thin-film modulator

A prototype was built of a fiber-optical communication system in which an He–Ne laser (λ = 0.63 μ) was the light source. A thin-film electro-optic Bragg-type modulator, utilizing a diffused layer in LiNbO₃, was employed in this system. Another component of the system was a 200-m long glass fiber with a step-like distribution of the refractive index (the losses in the fiber were ~8 dB/cm).