The HP/Agilent 81628B is an InGaAs optical power head engineered for high-accuracy measurement of optical power up to +40 dBm across the 800 nm to 1700 nm wavelength range. Its integrated sphere geometry distributes incident power over a large surface area, delivering excellent linearity and temperature stability essential for precision work at high power levels. The detachable heatsink enables sustained operation above 2 W, with operation above 34 dBm recommended only with heatsink attachment. The sensor delivers ±3.0% measurement uncertainty (970 nm to 1630 nm) and sub-0.10 dB linearity across the measurement range. An 8 mm aperture accommodates both fiber-coupled and open-beam inputs. Automatic power ranging, min/max monitoring, and data logging to 20k samples are standard.
Technical Specifications
• Sensor Element: InGaAs
• Wavelength Range: 800 nm to 1700 nm
• Power Range: +40 dBm to −60 dBm
• Maximum Input Power: +40 dBm (operation above +38 dBm at operator risk; damage threshold 40.5 dBm)
• Measurement Uncertainty: ±3.0% (970 nm to 1630 nm)
• Linearity (CW, 23°C ±5°C): ±0.03 dB to ±0.10 dB depending on power level (970 nm to 1630 nm)
• Return Loss: >75 dB typical; ±0.05 dB variation
• Noise Floor: <5 nW peak-to-peak; <1.2 nW (1255 nm to 1630 nm); <400 pW (800 nm to 1200 nm)
• Aperture Diameter: 8 mm
• Averaging Time: 100 µs to 10 s
• Operating Temperature: 0°C to +35°C (or 0°C to +40°C depending on configuration)
• Dimensions: 75 mm × 32 mm × 335 mm
• Weight: 0.6 kg
– Key Features
• Heatsink-equipped design for measurements above 2 W (34 dBm)
• Automatic power ranging with selectable averaging (100 µs to 10 s)
• Min/max value capture and data logging (up to 20k samples)
• Analog output interface
• Wavelength-dependent calibration built-in; OEM calibration available
– Compatibility & Integration
The 81628B interfaces with HP/Agilent optical power meter mainframes via the 81618A (single-channel) or 81619A (dual-channel) modules. Threaded fiber adapters from the Agilent 81000xx series support common connector types; the 81000BA bare fiber clamp operates to 34 dBm without heatsink. Open-beam input through the unobstructed 8 mm aperture is available when adapters are removed.
