The 918D-SL-OD1R Silicon Photodetector is designed for low optical power measurements and now features a new design with a diffuser for ISO 17025 compliance. It includes integrated calibration-data storage, built-in OD1 attenuation filter with automatic On/Off detection, temperature sensing electronics for temperature drift compensation and is compatible with DB15 based Newport Power Meters. The Silicon (Si) photodetector is NIST-traceable calibrated for 400-1100 nm optical power measurements. It includes a certificate of calibration with calibration curves and data for both attenuator on and off conditions.