Agilent/Keysight 81620C Optical Power Head

The Agilent/Keysight 81620C Optical Power Head is a precision measurement component featuring a large-area silicon detector optimized for optical power characterization across visible and near-infrared wavelengths. It integrates with the Keysight N7749C Optical Head Interface to enable flexible remote measurement in telecommunications, research, and manufacturing environments. The detector accepts parallel beams up to 4 mm diameter and is compatible with standard single-mode and multimode fiber (core ≤100 µm, NA ≤0.3), as well as open-beam applications via optional adapters.

Technical Specifications

• Detector: Silicon (Si), 5 mm diameter


• Wavelength Range: 450 nm to 1020 nm (specified 600 nm to 1020 nm)


• Power Measurement Range: –90 dBm to +10 dBm


• Maximum Safe Input Power: +16 dBm (CW and peak)


• Minimum Averaging Time: 100 µs


• Beam Input: Parallel beams up to 4 mm diameter; compatible with SM and MM fiber (core ≤100 µm, NA ≤0.3)


• Analog Output: 0 to 2 V (BNC connector), proportional to optical power. Configurable as linear or logarithmic scaling. Requires autoranging disabled for consistent output.


• Data Buffering: Dual 1 M sample buffers per head with internal or external triggering

Key Features

• Low-noise performance optimized for 850 nm measurements


• SCPI command set compatibility with Keysight optical power meters


• LAN and USB interfaces with built-in web-browser GUI


• Family-wide synchronized trigger architecture


• Rapid magnetic D-shaped adapters for fiber connector types and bare fibers

Typical Applications Optical power characterization in fiber-optic networks, photonics research, component manufacturing, and field testing requiring stable, low-noise measurements across the visible to near-infrared spectrum.

Compatibility & Integration Designed for operation with the Keysight N7749C Optical Head Interface. Also compatible with 8162-B and 8162-C series optical heads.