A plurality of computers in a network each have a processor and a non-volatile data storage device such as a hard disk, a raid array, or the like. The photodetector comprises a CCD provided with a protective member which is permeable to light in the wavelength band of the stimulated emission and impermeable to light in the wavelength band of the stimulating light. The system includes an inventive dual loop synchronizer that is optimized to improve the operating efficiency and reduce the overall latency of the read channel.