A tapping-mode near-field scanning optical microscope system with a bent optical fiber probe has been successfully developed to deliver the optical energy to the surface of cyanine dye layer of a commercial compact disk-recordable. The interference and damage result from the force-sensing laser beam can be avoided by using a bent fiber probe. Results of our optical writing showed the size of writing bits can be <40 nm. The estimated writing density may be 400 times higher than available commercially. We have also found the heating of metal coating at the end of fiber probe can perform thermal writing. Atomic force microscope images showed the raised edge of writing bits caused by this thermal writing effect. For the pure optical writing, we found the depth of writing bits should be controlled in a range less than the probe height maintained by the feedback electronics.