Wavelength multiplexing optical recording apparatus

A wavelength multiplexing optical recording apparatus comprising:

• an optical recording medium consisting of a plurality of laminated optical recording layers, said layers being recorded selectively by laser beams of different wavelengths;
• a plurality of laser sources of different wavelengths;
• and
• an optical system for focusing said laser beams on corresponding optical recording layers, said recording layers having distances of lamination made consistent with laser beam focal positions that are biased depending on the wavelength of said laser beam caused by the chromatic aberration of said focusing optical system.

A wavelength multiplexing optical recording apparatus comprising:

• an optical recording medium consisting of a plurality of laminated optical recording layers having wavelength sensitivities, with a light reflective layer being disposed at the final layer position seen from the light incident surface;
• a plurality of laser sources of different wavelengths;
• and
• an optical system for focusing said laser beams of different wavelengths, any of a laser beam having a wavelength for recording and reproducing selectively the recording layer nearest to said reflective layer and a laser beam having a wavelength which does not interact with any of said wavelength selective recording layers is used for the detection of focal point bias and the detection of tracking error.