Agilent/Keysight 81628C,Optical Head (Dual Channel)

The Agilent/Keysight 81628C is a dual-channel optical head engineered for high-power optical measurements across the near-infrared spectrum. Built around an InGaAs detector with integrating sphere technology, it delivers the highest accuracy in its product family at elevated optical power levels and interfaces directly with the Keysight N7749C optical head interface for integrated test automation.

Technical Specifications

• Detector Type: InGaAs with integrating sphere


• Wavelength Range: 800 nm to 1700 nm


• Maximum Input Power: +40 dBm (with included heat sink)


• Input Signal Acceptance: Single-mode fiber (NA ≤ 0.2), multi-mode fiber (NA ≤ 0.4), parallel beams up to 3 mm diameter


• Aperture Diameter: 8 mm


• Measurement Averaging: 100 µs to 10 s


• Data Logging: Dual 1M sample buffers with internal or external triggering


• Operating Humidity: Maximum 80% relative humidity, non-condensing


• Operating Altitude: Up to 2000 m

Key Features

• Dual 1M sample buffers enable continuous data acquisition with flexible trigger modes


• Analog output provides linear or logarithmic voltage signals proportional to optical power, ideal for closed-loop alignment systems


• High-power integrating sphere optimized for accurate measurements at elevated signal levels


• Flexible input accommodation across single-mode, multi-mode, and free-space configurations

Typical Applications High-power optical power characterization, automated fiber-optic alignment, optical transmission testing, and laboratory optical power measurement where broad spectral coverage and measurement accuracy at high power levels are required.

Compatibility & Integration Designed for the Keysight N7749C optical head interface. Backward compatible with previous-generation optical heads including 81620B and 81628B. Supports a wide range of fiber connector adapters, bare fibers, and open-beam configurations.