Can an optical power meter measure current

Optical power meters with current measurement capability allow simultaneous measurement of optical power and the photocurrent generated by photodiodes, enabling precise characterization of optical devices.

Overview

An optical power meter (OPM) is a device used to measure the power of an optical signal, typically in fiber optic systems. Standard OPMs consist of a calibrated photodiode sensor, a measuring amplifier, and a display. The photodiode converts incident light into a current, which is then amplified and displayed as optical power. Some advanced OPMs also allow direct measurement of the photocurrent, providing additional insight into device performance and enabling I-L (current vs. optical power) characterization .

Devices with Current Measurement

1. Artifex OPM500
   • Measures optical power from pW to mW using a photodiode.
   • Outputs a voltage linearly proportional to the input power, with the photocurrent also readable via USB.
   • Features a transimpedance amplifier to convert photodiode current to voltage.
   • Supports software-triggered or continuous measurement, with sampling rates up to 600 S/s.
   • Includes gain control, bandwidth adjustment, and polarity inversion for flexible measurement setups .
2. Yokogawa AQ23212A
   • Designed for optical transceiver testing.
   • Measures optical power, PD current, modulator current, and DC extinction ratio.
   • Can monitor optical insertion loss and detect optical input interruptions.
   • Suitable for multi-application testing where both optical power and electrical current are critical parameters .

Additional Options

• Thorlabs PM100 series: Offers consoles paired with photodiode sensors that provide calibrated optical power measurements. While primarily focused on power, some sensor heads allow monitoring of photocurrent indirectly through software interfaces .
• Newport and ILX Lightwave meters: Provide benchtop and handheld optical power meters with high accuracy and compatibility with various calibrated sensors. Some models can output electrical signals proportional to optical power, which can be interpreted as current with appropriate calibration .

Key Considerations

• Sensor Type: Photodiode sensors are fast and sensitive, ideal for current measurement, but wavelength-dependent. Thermopile sensors are less wavelength-sensitive but do not provide current output.
• Interface: USB or analog outputs allow integration with PCs or data acquisition systems for real-time current monitoring.
• Dynamic Range: Ensure the meter covers the expected optical power range and corresponding photocurrent.
• Calibration: Devices should be calibrated with traceable standards to ensure accurate power and current readings.

Conclusion

For applications requiring both optical power and current measurement, devices like the Artifex OPM500 and Yokogawa AQ23212A are suitable choices. They provide direct access to the photodiode current, flexible measurement modes, and integration options for automated testing or detailed optical characterization. When selecting a meter, consider sensor type, wavelength range, interface options, and calibration requirements to match your specific application needs .