HP / Agilent 81525A High power InGaAs Optical Head, 5mm

The HP/Agilent 81525A is a high-power InGaAs optical head designed for precise optical power measurements across the near-infrared spectrum. Built around a 5 mm InGaAs detector element, this optical head delivers measurement accuracy of ±3.0% across 900 nm to 1600 nm and handles power levels from –70 dBm to +27 dBm, making it suitable for both low-level and high-power optical signal characterization. The head exhibits low polarization-dependent loss and high return loss, critical for accurate testing of optical components and systems.

Technical Specifications

Sensor Type: InGaAs

Detector Area: 5 mm

Wavelength Range: 800 nm to 1650 nm

Power Measurement Range: –70 dBm to +27 dBm (1250–1650 nm); –70 dBm to +23 dBm (800–1250 nm)

Measurement Accuracy: ±3.0% (900–1600 nm)

Wavelength Accuracy: ±3.0% (900–1600 nm)

Polarization Sensitivity: Low PDL

Return Loss: High

Warm-up Time: 15 minutes

Recalibration Interval: 1 year

Physical Dimensions: 50 mm diameter × 30 mm length

Net Weight: 0.1 kg

Key Features

5 mm detector element optimized for high-power measurements

Wide spectral coverage from 800 nm to 1650 nm

Dynamic range spanning seven decades of optical power (–70 to +27 dBm)

Low PDL and high return loss for demanding optical test applications

Attenuation at 850 nm printed on lens; calibration entry via CAL parameter required for precise measurements

Multiple connector interface options available

Typical Applications

Optical power measurement in fiber-optic communication systems

High-power signal characterization

Optical component and subsystem testing

Low and high dynamic range power monitoring

Compatibility & Integration The 81525A integrates with HP/Agilent mainframe units including the 8153A, 8163, 8166, 8163A, and 8164A through interface modules 81533A or 81533B. Product Status: Obsolete. No longer sold by Keysight; replacement model is the Keysight 81626B High Power Optical Head.