Optical Power Meter Burn-in

Burn-in for an optical power meter involves a controlled warm-up period to stabilize the sensor and ensure accurate, repeatable measurements.

What Burn-in Means

Burn-in is a process where an optical power meter or its sensor is operated for a period of time under controlled conditions before it is used for precise measurements. This is particularly relevant for photodiode and thermopile sensors, which may exhibit slight changes in sensitivity or baseline readings when first powered on or after long storage . Burn-in helps the sensor reach a stable operating temperature and electrical equilibrium.

Why Burn-in is Important

1. Stabilizes Sensor Response: Newly powered sensors can show drift in readings due to thermal effects or initial electronic settling. Burn-in minimizes these fluctuations.
2. Improves Accuracy: Optical power meters are calibrated to national standards (e.g., NIST traceable), but sensor instability can temporarily affect measurement accuracy .
3. Extends Sensor Life: Gradual conditioning reduces stress on sensitive photodiodes or thermopiles, which can improve long-term reliability.

Typical Burn-in Procedure

• Warm-up Time: Most optical power meters require a warm-up period of 5–30 minutes, depending on the sensor type and ambient conditions .
• Continuous Illumination: Some users expose the sensor to a low-level optical signal during burn-in to stabilize the photodiode response.
• Environmental Stability: Keep the sensor in a stable temperature and avoid sudden changes in light intensity during burn-in.

Best Practices

• Always follow the manufacturer's recommendations for warm-up and burn-in. For example, Thorlabs and Newport sensors suggest allowing the sensor to stabilize before taking critical measurements .
• Avoid exposing the sensor to high optical power immediately after powering on, as this can cause temporary nonlinearity or damage.
• Periodically recalibrate the sensor if it has been stored for long periods or after extended use.

Summary

Burn-in is a preventive and stabilizing step for optical power meters that ensures accurate, repeatable, and reliable measurements. While not all meters require extensive burn-in, allowing the sensor to warm up and stabilize is a standard practice in fiber optic testing and laser characterization . Proper burn-in, combined with calibration, helps maintain the precision of optical power measurements over time.