{HEAD ~ The determined PthO} and the PcO are used to determine {TAIL ~ the write power} threshold Pth that satisfies the equation Pth=PthO+PcO. The determined Pth value is, for instance, multiplied by the ratio α between Popt and Pth, which is set for each optical disc, to determine the optimum write power Popt 
used to determine
{ HEAD ~ The determined PthO } and the PcO are used to determine { TAIL ~ the write power } threshold Pth that satisfies the equation Pth = PthO+PcO. The determined Pth value is , for instance , multiplied by the ratio α between Popt and Pth , which is set for each optical disc , to determine the optimum write power Popt
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH