The 918D-IR-OD3R Germanium Photodetector is designed for low optical power measurements. It features include integrated calibration-data storage, built-in OD3 attenuation filter with automatic On/Off detection, temperature sensing electronics for temperature drift compensation and is compatible with DB15 based Newport Power Meters. The Germanium (Ge) photodetector is NIST-traceable calibrated for 780-1800 nm optical power measurements. It includes a certificate of calibration with calibration curves and data for both attenuator on and off conditions.
These photodiodes show excellent linearity over a large dynamic range. This is ideal for use in applications that require high accuracy measurements down to the pW level, especially when combined with a high sensitivity power meter that can accommodate the large dynamic range of the optical signal.
A natural characteristic of a photodiode is for the its optical response to change as the temperature changes near the bandgap of semiconductor materials. Newport’s 918D series sensors feature a thermocouple near the photodiode, which allows certain Newport meters to read the temperature and automatically adjust the responsivity, ensuring the most accurate measurements.
The maximum measurable power of photodiode sensors is dependent on several factors such as the wavelength of incoming light, photodiode current output saturation, temperature, use of an attenuator and a power meter's maximum current input value. Newport provides maximum power specifications based on the power meter models, with and without an attenuator, and wavelength-dependent maximum power level. With these factors affecting measurable power in mind, choosing the proper detector for your application is critical.
The attenuator on/off sensor is built into the detector head. When a 918D series detector is connected to power meter models 1936-R, 2936-R, 1919-R, 841-PE-USB, and the 1830-R series, the meter automatically switches the responsivity value. The user does not need to update the power meter setup. The detector is calibrated with the integrated attenuator and without it, and the data is saved in the EEPROM.
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