Agilent/Keysight 81624B Optical Power Head

The Keysight 81624B is a high-sensitivity InGaAs optical power head engineered for precision optical power measurement across the 800 nm to 1700 nm wavelength range. This remote detector head integrates with Keysight's Lightwave Measurement platform via interface modules (81618A or 81619A) and 816xB series mainframes, delivering measurement capabilities from +10 dBm to -90 dBm with exceptional linearity and low polarization dependence. The 5 mm diameter InGaAs detector accommodates standard single-mode and multimode fibers (max. 100 µm core, NA < 0.3) through a flexible connector interface palette supporting FC/PC, SC/PC, E-2000, and bare fiber configurations.

Technical Specifications

• Detector Type: InGaAs with 5 mm diameter, large area design


• Wavelength Range: 800 nm to 1700 nm


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


• Linearity (CW): -70 dBm to +10 dBm


• Measurement Uncertainty at Reference Conditions (-20 dBm, 1000–1630 nm): ±2.2%


• Polarization Dependence: ±0.002 dB typical; ≤ ±0.005 dB maximum


• Spectral Ripple Uncertainty: < ±0.002 dB typical; ≤ ±0.005 dB maximum


• Analog Output: Included


• Applicable Fiber Types: Single-mode and multimode (max. 100 µm core, NA < 0.3)

Key Features

• Averaging time settings from 100 µs to 10 s with automatic power ranging


• Minimum and maximum value monitoring with up to 20k sample logging capability


• Large area detector minimizes connector misalignment effects, ensuring repeatable results


• Lower power density per unit area supports high power measurements with superior linearity


• Designed for low return loss and minimal wavelength-dependent measurement drift

Typical Applications

• Optical component characterization and fiber optic link assessment


• Photonics research requiring high-accuracy power measurement


• Wavelength-sensitive optical testing across the near-infrared spectrum

Compatibility & Integration Interface Modules: Agilent 81618A (single-channel) or 81619A (dual-channel) Mainframes: 8163B, 8164B, 8166B multichannel mainframes Connector Options: Magnetic D-shape adapter, removable 81624DD adapter ring, with interchangeable connectors (81000FA FC/PC, 81000KA SC/PC, 81000PA E-2000), MT ribbon fiber, and bare fiber clamp support.