The HP/Agilent 81656A is a 1550 nm Fabry-Perot laser source module delivering +13 dBm (20 mW) output power for optical component characterization. Built on InGaAsP technology with a standard 9/125 µm single-mode fiber interface, this source provides exceptional short- and long-term power stability (±0.005 dB over 15 minutes, ±0.03 dB over 24 hours) and exhibits insensitivity to back reflections at RL ≥ 14 dB. The module integrates digital modulation capability with selectable rates from 270 Hz to 10 kHz, variable output attenuation from 0 to 6 dB in 0.1 dB steps, and improved coherence control for linewidth broadening.
Technical Specifications
• Laser Type: Fabry-Perot Laser Diode
• Sensor Element: InGaAsP
• Center Wavelength: 1550 nm ±15 nm
• Output Power: >+13 dBm (20 mW)
• Spectral Bandwidth (RMS): <7.5 nm, <4.5 nm
• Fiber Type: Standard Single-Mode 9/125 µm
• CW Power Stability (15 min): <±0.005 dB
• CW Power Stability (24h): <±0.03 dB
• Output Attenuation: 0 dB to 6 dB in 0.1 dB steps
• Back Reflection Insensitivity: ≥14 dB return loss
• Digital Modulation: 270 Hz, 330 Hz, 1 kHz, 2 kHz, 200 kHz to 10 kHz
• Modulation Output: Pulse shaped, 50% duty cycle
• Optical Connector: Standard interface (Diamond HMS-10/Agilent recommended)
• Dimensions: 2.8 × 1.3 × 13.2 in
• Weight: 0.5 kg
– Key Features
• Stabilized performance for both short- and long-term laboratory use
• Internal digital modulation with flexible frequency selection
• Variable output attenuation for precise power control
• Insensitive to back reflections, enabling direct component measurement without isolators
• Coherence control for broadening applications
– Typical Applications
• Insertion loss and optical return loss measurements
• Polarization-dependent loss (PDL) characterization
• Broadband optical component testing
– Compatibility & Integration
Designed for modular integration with Agilent 8163A/B, 8164A/B, and 8166A/B Lightwave systems. Works in conjunction with optical power meter modules. Optical interface connectors sold separately.
