Agilent/Keysight 81609A Tunable Laser Module (1480–1640 nm)

The Keysight 81609A is a step-tunable laser module delivering continuous-wave output across the 1480–1640 nm band. Engineered for DWDM system testing, component characterization, and optical research, this module combines narrow 10 kHz spectral width with ±10 pm absolute wavelength accuracy and ±3 pm repeatability. Peak output power exceeds +12 dBm (or +13 dBm depending on configuration) with user-adjustable attenuation to 0 dBm, while maintaining ±0.01 dB power stability over one hour.

The module steps to discrete wavelengths in 300 ms per 1 nm increment and features 0.1 pm resolution tuning. Polarization-maintaining fiber coupling (Panda-type, angled connector standard) ensures stable signal delivery with ≥75 dB/nm SSE ratio. Operating temperature range spans −40 °C to 70 °C; warm-up time is 60 minutes.

The 81609A installs in Keysight 8163A/B, 8164A/B, and 8166A/B mainframes and integrates with N774xA multiport power meters and N7700A software for swept-wavelength measurement capabilities.

Technical Specifications

• Wavelength Range: 1480–1640 nm


• Tuning Resolution: 0.1 pm


• Tuning Speed: 300 ms per 1 nm step


• Spectral Width: 10 kHz


• Output Power: +12 dBm peak (typical, standard options); +13 dBm peak (typical, option 113); user-adjustable down to 0 dBm


• Power Stability: ±0.01 dB over one hour


• Absolute Wavelength Accuracy: ±10 pm (typical)


• Wavelength Repeatability: ±3 pm (typical)


• Signal-to-Spontaneous Emission Ratio: ≥75 dB/nm (typical)


• Output Mode: Continuous Wave (CW)


• Fiber Coupling: Polarization-maintaining (PMF), Panda-type, angled connectors (standard)


• Operating Temperature: −40 °C to 70 °C


• Warm-up Time: 60 minutes


• Laser Classification: Class 3B per IEC 60825-1

Key Features

• Step-tunable architecture with 0.1 pm resolution enables precise wavelength selection across the C-band extension


• Exceptional linewidth and SSE ratio support demanding filter and component measurements


• High repeatability (±3 pm) minimizes recalibration requirements between test cycles


• Flexible output power control from +13 dBm to 0 dBm in a single module


• Angled PMF connector (Option 072, standard) reduces back-reflection


• Wide operating temperature range accommodates laboratory and field environments

Typical Applications

• DWDM system validation and channel characterization


• Optical filter and multiplexer testing


• Laser and photodiode performance evaluation


• Wavelength-dependent loss and dispersion measurement

Compatibility & Integration

• Mainframes: 8163A/B, 8164A/B, 8166A/B Lightwave Systems


• Power meters: N774xA multiport or 816xxx module-based systems


• Software: N7700A suite for swept-wavelength operation


• Panel interface: Two BNC connectors (front), ±6 V absolute maximum per connector