Agilent/Keysight 81689A,Agilent Keysight 81689A Tunable Laser Source

The Agilent/Keysight 81689A is a compact tunable laser module engineered for precision optical testing across the C-band spectrum. It delivers continuous, mode-hop-free tuning with stable output power, making it the ideal source for characterizing optical amplifiers, DWDM components, and complete DWDM systems. The module integrates into Agilent’s 8163A/B, 8164A/B, and 8166A/B mainframe platforms, providing flexible wavelength control with exceptional repeatability and spectral purity.

– Technical Specifications

Wavelength Performance:
• Tuning Range: 1525 nm to 1575 nm (C-band)
• Resolution: 0.01 nm (1.25 GHz at 1550 nm)
• Absolute Accuracy: ±0.3 nm
• Repeatability: ±0.05 nm
• Stability: ±0.02 nm over 24 hours at constant temperature
• Spectral Linewidth: 20 MHz (typical)

Optical Output:
• Continuous Power: ≥ 6 dBm across 1525–1575 nm
• Minimum Power: −3 dBm
• Power Stability: ±0.03 dB over 1 hour
• Tuning Speed: < 10 seconds per 50 nm
• Output Isolation: 38 dB (typical)
• Return Loss: 55 dB (with angled or polarization-maintaining fiber options)

Modulation Capability:
• Internal Digital: 200 Hz to 1 MHz (duty cycle dependent)
• External Digital: 200 Hz to 1 MHz, fall time < 300 ns
• Reference/Control: TTL signals via mainframe

– Key Features

• Mode-hop-free tuning ensures clean wavelength transitions without spectral noise
• Fine 0.01 nm resolution enables precise channel spacing validation in DWDM systems
• Excellent wavelength stability (±0.02 nm/24 h) reduces test uncertainty
• Multiple fiber and connector options: standard single-mode (straight/angled) and polarization-maintaining Panda fiber configurations
• Compact module design fits within existing Agilent lightwave platforms
• Warm-up time under 40 minutes with immediate operation capability

– Typical Applications

• Optical amplifier gain and noise figure characterization
• DWDM filter and multiplexer testing
• Component wavelength and power response mapping
• Full DWDM system validation across the C-band
• Tunable laser source replacement and upgrade scenarios

– Compatibility & Integration

The 81689A operates as a plug-in module for Agilent 8163A/B Lightwave Multimeters, 8164A/B Lightwave Measurement Systems, and 8166A/B Lightwave Multichannel Systems. Wavelength and modulation control flow through the host mainframe interface, eliminating the need for standalone instrumentation.