A piece of glass fiber or rod with a radially parabolic vaiation of refractive index, named SELFOC(.4), has been prepared by exchanging thallium ions for potassium ions. As a light guide for optical communication use, SELFOC(.4)fiber has many advantages over reported ones from the view-point of flexibility, distortion of optical pulse, economical production, etc. The mode pattern of a laser beam was scarcely deformed after passing through a SELFOC()fiber, curved in a radius of curvature 10 cm, of one meter in length and 0.25 mm in diameter. SELFOC(g)fiber was used as connectors in an experimental optical com-munication system. 11-0 Attenuation in SELFOC '-- fiber has been decreased to a value 80 - 250 dB/km at 0.63A and will be still improved. Then, long SELFOCQV cables may be utilized for a long distance transmission line. A cylindrical rod of SELFOC() has the same optical performance as that of a single or sequence of optical lens. Although its resolving power under white light illumination is still poor, a short SELFOC () lens and a SELFOCTO fiber of 10 cm in length can be applied to medical endoscopes. Further, a conical 814.1,110C(,) was used to guide a 1aser beam on the small surface of an avalanche photo-diode. SELFOC( will be widely utilized in optical communication, optic, ,1 data processing, optical instruments and opto-electronic devices.