918D High Performance Calibrated Photodiode Sensors

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918d calibrated photo diode power sensor

Overview

918D Series advanced free space photodiode sensors are calibrated for use with newport power meters. They feature a built-in, switchable attenuator with an On/Off sensor for the power meter and a temperature sensor to adjust for temperature dependent responsivity changes. Utilizing NIST-traceable standards and calibrated with high-precision equipment these optical power detectors offer the lowest calibration uncertainty in industry.

NIST traceable calibration with lowest uncertainty available
Switchable internal attenuator with On/Off position sensor
Internal temperature sensor for thermal drift compensation
OD1, OD2 and OD3 (10x, 100x and 1000x) attenuators available
Optional screw in fiber-optic adapters for fiber power measurement
RoHS compliant

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Products

Compare	Model	Compatibility	rankScore	Spectral Range	Maximum Measurable Power¹	Minimum Measurable Power²	Availability	Price	Brand
918D-IG-OD1R Optical Power Detector, InGaAs, 800-1650 nm, OD1 Attenuator $1,631 6 Weeks	918D-IG-OD1R Optical Power Detector, InGaAs, 800-1650 nm, OD1 Attenuator	UNIVERSAL	1.0	800 - 1650 nm	100 mW	20 pW	6 Weeks	$1,631	Newport
918D-IG-OD2R Optical Power Detector, InGaAs, 800-1650 nm, OD2 Attenuator $1,590 In Stock	918D-IG-OD2R Optical Power Detector, InGaAs, 800-1650 nm, OD2 Attenuator	UNIVERSAL	1.0	800 - 1650 nm	1000 mW	20 pW	In Stock	$1,590	Newport
918D-IG-OD3R Optical Power Detector, InGaAs, 800-1650 nm, OD3 Attenuator $1,375 In Stock	918D-IG-OD3R Optical Power Detector, InGaAs, 800-1650 nm, OD3 Attenuator	UNIVERSAL	1.0	800 - 1650 nm	2000 mW	20 pW	In Stock	$1,375	Newport
918D-IR-OD1R Optical Power Detector, Germanium, 780-1800 nm, OD1 Attenuator $930 In Stock	918D-IR-OD1R Optical Power Detector, Germanium, 780-1800 nm, OD1 Attenuator	UNIVERSAL	1.0	780 - 1800 nm	100 mW	5 nW	In Stock	$930	Newport
918D-IR-OD2R Optical Power Detector, Germanium, 780-1800 nm, OD2 Attenuator $1,009 In Stock	918D-IR-OD2R Optical Power Detector, Germanium, 780-1800 nm, OD2 Attenuator	UNIVERSAL	1.0	780 - 1800 nm	1000 mW	5 nW	In Stock	$1,009	Newport
918D-IR-OD3R Optical Power Detector, Germanium, 780-1800 nm, OD3 Attenuator $841 Show	918D-IR-OD3R Optical Power Detector, Germanium, 780-1800 nm, OD3 Attenuator	UNIVERSAL	1.0	780 - 1800 nm	2000 mW	5 nW	Show	$841	Newport
918D-SL-OD1R Optical Power Detector, Silicon, 400-1100 nm, OD1 Attenuator $790 In Stock	918D-SL-OD1R Optical Power Detector, Silicon, 400-1100 nm, OD1 Attenuator	UNIVERSAL	1.0	400 - 1100 nm	40 mW	20 pW	In Stock	$790	Newport
918D-SL-OD2R Optical Power Detector, Silicon, 400-1100 nm, OD2 Attenuator $851 In Stock	918D-SL-OD2R Optical Power Detector, Silicon, 400-1100 nm, OD2 Attenuator	UNIVERSAL	1.0	400 - 1100 nm	400 mW	20 pW	In Stock	$851	Newport
918D-SL-OD3R Optical Power Detector, Silicon, 400-1100 nm, OD3 Attenuator $721 In Stock	918D-SL-OD3R Optical Power Detector, Silicon, 400-1100 nm, OD3 Attenuator	UNIVERSAL	1.0	400 - 1100 nm	2000 mW	20 pW	In Stock	$721	Newport
918D-UV-OD3R UV Silicon Detector, 200-1100 nm, OD3 Attenuator $857 In Stock	918D-UV-OD3R UV Silicon Detector, 200-1100 nm, OD3 Attenuator	UNIVERSAL	1.0	200 - 1100 nm	200 mW	20 pW	In Stock	$857	Newport

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Notes:

When used with a 1830-R, 1918-R, 1936-R, or 2936-R benchtop optical power meter.
When used with a 1936-R or 2936-R benchtop optical power meter.

Features

Excellent Photodiode Linearity

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.

Responsivity Variation over Temperature

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.

Factors that Affect Maximum Measurable Power

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.

Attenuator On/Off Sensor

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.

Wide Dynamic Range with OD3 Attenuator

The 884 Series OD3 attenuators extend the calibrated optical dynamic range of our detectors by three decades. Both the attenuator and detector have their serial number scribed on the part which, to maintain calibration, must match. Our attenuator design provides high damage threshold and spectral flatness. With the low noise equivalent power (NEP) associated with the photodiodes being used, a wider dynamic range is achieved. The clear aperture of the 884 Series attenuators is 10.3 mm.

NIST-traceable Sensor Calibration

Our calibrated photodiode sensors include a full spectral response calibration utilizing NIST-traceable standards calibrated with high-precision equipment maintained in Newport’s optical detector calibration facility. Tight calibration facility and process control allows the tightest calibration uncertainty in industry. Each detector is shipped with the calibration data, which is electronically stored inside the detector's EEPROM. A certificate of calibration as well as the actual calibration curves and data are shipped with each detector for attenuator and no attenuator models. To maintain accuracy and guarantee performance, Newport recommends annual photodiode detector calibration.

Detector calibration system block diagram.

Internal Temperature Sensor

The internal temperature sensor on the detector head is used to compensate the responsivity drift caused by the temperature change in the photodiode. The responsivity change is most sensitive around the bandgap, or towards the longer wavelength limit. The power meter calculates the temperature and automatically updates the responsivity value so that the measurements remain accurate. This feature is enabled with the power meter models 1936-R, 2936-R, 1919-R, and 844-PE-USB.

Adapters for Fiber-Optic Applications

These photodiode sensors can be converted to measure optical power from connectorized or bare optical fibers. Newport offers a comprehensive set of screw-in fiber-optic adapters to match a variety of connector types. Our bare fiber holder and adapter mount are designed together to hold 250-µm bare fibers without damaging the fiber.

Photodiode Sensor Physics

A photodiode consists of a semiconductor p-n junction similar to a laser diode and LED However, the fundamental radiation process involved is absorption. Light falling on the junction causes the formation of electron-hole pairs. In photovoltaic mode, the electron-hole pairs migrate to opposite sides of the junction, thus producing a voltage. One critical difference between a semiconductor photon source and a photon detector is that the former requires the use of a direct-gap semiconductor while the latter can utilize an indirectgap semiconductor. While the simultaneous requirement for energy and momentum conservation makes photon emission much less likely in indirect-gap semiconductors, this is not the case for absorption. A readily-achievable two-step process occurs where an electron is excited to a high level in the conduction band followed by a relaxation process where its momentum is transferred to phonons. Since this process can be sequential, it is much more likely than an emission process where the two steps must occur simultaneously. Please see our Photodiode Sensor Physics technical note for additional information.