A common optical microfiber has usually been required to have very low loss so as to satisfy the research of optical microfiber based components. On the contrary, optical microfibers with special characteristics and a little higher loss are experimentally studied in this paper, just by modifying some of the parameters related to the optical microfiber fabrication system. Some optical microfibers have high backscattering characteristic, some have a little higher absorption loss. We have fabricated a kind of OM with high backscattering and no more than 5 mm waist region length, which can be evaluated as a reflector with low reflectance. The reflection function has been demonstrated by using the OM reflector as one of the two reflectors in a Fabry-Perot interferometer. We have also controlled the size and loss of OM to enhance its optical induced thermal effect. The OM is injected with intensity-modulated 980 nm light with average light power of about several milliwatts, the optical phase in the OM at 1550 nm wavelength is measured to be modulated while the OM is inserted into a Michelson interferometer. The result show that the OM acts as a kind of optical modulating material based on the optical induced thermal effect. In conclusion, OMs have been studied to evaluate reflection function and thermal modulation function, OM will become a kind of functional fiber and have potential value on research of new OM components.