Writable optical disk recording apparatus

A writable optical disk recording apparatus for writing arbitrary data on a writable disk by using a laser beam comprising:

• (a) means for effecting a trial writing on said writable disk at a recording characteristic check area, reproducing a recorded calibration signal from the recording characteristic check area and using the reproduced calibration signal to thereby control an output power of said laser beam and recording a first signal of a shortest bit length and a second signal of an arbitrary bit length longer than the shortest bit length in the recording characteristic check area using the laser beam whose output power is controlled by using the calibration signal;
• (b) means for reproducing and separately storing as a first reference signal and a second reference signal the first signal and the second signal from the characteristic check area;
• and
• (c) means for simultaneously reproducing recorded data signals during subsequent recording of data in a data area of the writable disk and comparing a level of a reflected signal provided when signals of the shortest bit length and the arbitrary longer bit length are recorded with the first reference signal and the second reference signal and accordingly controlling the output power of said laser beam.