Agilent/Keysight 81640A Tunable Laser Source

The Agilent/Keysight 81640A Tunable Laser Source is a precision optical module engineered for wavelength-critical applications in optical communications and component testing. Operating across the 1510–1640 nm band with mode-hop-free tuning, the 81640A delivers ±0.015 nm absolute wavelength accuracy and ±0.5 pm repeatability, supported by a built-in wavelength control loop and exceptional 24-hour stability of ±1 pm at constant temperature.

Technical Specifications

• Wavelength Range: 1510 nm to 1640 nm


• Maximum Output Power: 4 dBm


• Absolute Wavelength Accuracy: ±0.015 nm


• Wavelength Repeatability: ±0.5 pm (typical)


• Wavelength Stability: ≤±1 pm (typical, 24 hours at constant temperature)


• Tuning Speed: 400 ms (1 nm step), 600 ms (10 nm step), 2.8 s (100 nm step)


• Linewidth (coherence control off): 100 kHz (typical)


• Effective Linewidth (coherence control on): >50 MHz (typical)


• Optical Attenuator Range: >60 dB (Output 2 available)


• Connector Options: Polarization-maintaining fiber with straight contact (Option 071) or angled contact (Option 072)

Key Features

• Mode-hop-free tuning across full wavelength range


• Continuous sweep capability


• Dual optical outputs: ultra-low spontaneous emission (SSE) and high power


• Ultra-low SSE output optimized for crosstalk measurements and component characterization (Fiber Bragg Gratings)


• Angled connectors (Option 072) reduce back-reflected light for improved return loss in high-sensitivity environments


• Built-in wavelength control loop ensures measurement confidence

Typical Applications

• Dense-wavelength division multiplexing (DWDM) passive component testing


• Optical amplifier characterization


• Fiber Bragg Grating measurement and evaluation


• Crosstalk and insertion loss assessment

Compatibility & Integration The 81640A is a back-loadable module for the Agilent 8164A Lightwave Measurement System. The 81640B is the current replacement; upgrade paths are available.