Old CD player relies on mechanical accuracy for tracking, new player uses tracking logic technology; detect and adjust at laser head more, mechanical parts no longer need accuracy, made CD player much cheaper.
Laser diode wattage was higher because of less sensitive laser detector.
Laser diode's wave length is different. new CD player has same wave length as DVD player (components sharing). wave length is selected to help detect layers; depth of reflective layers for DVD.
maybe...
