The wavelength of the laser diode used in CD players is typically around 780 nanometers. Laser diode substrate is like a square, a box, it emites for two sides, one side to the laser diode ouput, andthe other for the monitor diode, it helps to perform it a way it keeps a constant power. There is as data that is not well known but it is very important for CD readers, is S/N. The package features a CAN-type structure with a sealed glass window, providing a high degree of reliability under virtually any environment. An optically transparent real index guide is utilized to. Furthermore, the two diodes (laser- & photo- ) usually share one pin, often ground.