Reading bits on a CD‐ROM without a photodiode

Abstract

Abstract:We demonstrate that the bits of a CD-ROM can be read without a photodiode (PD). A commercial CD-ROM drive was used and left unmodified except a beam splitter was removed which would route the light to a PD. This allowed for the reflected light to be incident on the laser within the laser package itself. By monitoring fluctuations in the voltage across the laser diode (LD) under constant-current injection, it was possible to read and interpret the bits from a spinning CD-ROM.