Optical fibers, in particular, glass fibers, are mostly used in the field of optical communication, however in recent years new optical sensors based on the optical fibers have been reported in literature and produced commercially. Extrinsic and intrinsic character of the fibers have been implemented in development of such sensing devices. Glass Optical Fibers (GOF) because of low attenuation are more suitable for the optical communication purposes while Plastic Optical Fibers are advantageous for the linking purpose and some sensing operations. Considering this point different (POF) optical fiber sensors have been developed by author to show potential applications of POFs in sensor technology. New simple devices at the minimum cost are introduced in this study. Results for light reflection sensing, light leakage sensing, level sensing, and distance gauging are obtained. Presented systems are mostly in bulk form, however, these devices with good results show that in principle, these ideas can be implemented in design of small scale devices. It seems to be a great potential to apply these ideas in order to develop new devices suitable for compact and integrated applications. In this article some examples are given in which the reported results verify the concept and applicability of such devices for future sensing technology.