The Agilent/Keysight 81651A is a single-wavelength Fabry-Perot laser source module designed for optical characterization of broadband components and fiber optic systems. Operating at 1550 nm ± 15 nm, this module delivers > 0 dBm output power with exceptional stability and insensitivity to back reflections, making it ideal for insertion loss, optical return loss, and PDL measurements. The module integrates internal digital modulation, coherence control, and precision output attenuation for flexible test configurations.
Technical Specifications
• Laser Type: Fabry-Perot laser diode
• Center Wavelength: 1550 nm ± 15 nm
• Output Power: > 0 dBm (1 mW)
• CW Power Stability:
– Short term (15 min): < ± 0.005 dB typical
– Long term (24 h): ± 0.03 dB typical
– Back reflection insensitivity (RL ≥ 14 dB): ± 0.003 dB typical
• Spectral Bandwidth (rms): < 4.5 nm
• Fiber Output: Single-mode 9/125 µm
• Output Attenuation: 0 dB to 6 dB in 0.1 dB steps
• Operating Temperature: 0°C to +45°C
• Warm-up Time: 60 minutes
– Key Features
• Internal digital modulation with fixed frequencies at 270 Hz, 330 Hz, 1 kHz, and 2 kHz, plus free selection from 200 Hz to 10 kHz
• Pulse-shaped modulation output with 50% duty cycle
• Coherence control for linewidth broadening
• Stabilized output suitable for both short-term and long-term applications
• Class 1 laser safety per IEC 60825-1 (2001) and 21 CFR 1040.10 (1995)
• Compact form factor: 75 mm × 32 mm × 335 mm, weighing 0.5 kg
– Typical Applications
• Insertion loss measurement on optical components
• Optical return loss characterization
• Polarization-dependent loss (PDL) testing
• Fiber optic system validation
– Compatibility & Integration
The 81651A operates as a plug-in module within compatible mainframe systems paired with optical power meter modules. Part of a series including 81650A, 81652A, 81654A, 81655A, 81656A, and 81657A variants. Note: This is an obsolete product.
