Agilent/Keysight 71400C – Lightwave Signal Analyzer

The Agilent/Keysight 71400C Lightwave Signal Analyzer characterizes optical devices - semiconductor lasers, laser transmitters, optical modulators, and detectors - by combining microwave and RF spectrum analysis with a sensitive, wide-bandwidth optical receiver. The instrument delivers calibrated measurements across baseband intensity modulation, harmonics, and noise floor analysis to 22 GHz, essential for fiber-optic communications development and production test.

Technical Specifications

Frequency and Wavelength Range

• Electrical bandwidth: 100 kHz to 22 GHz


• Standard wavelength operation: 1200 nm to 1600 nm


• Option 850 wavelength range: 750 nm to 870 nm Optical Receiver Module (Agilent 70810B)


• Optical sensitivity: −60 dBm (10 Hz bandwidth)


• Displayed average noise level: better than −65 dBm (optical) in 10 Hz bandwidth


• Built-in optical attenuator: enables measurements up to 1 watt laser power


• Integrated optical power meter with analog and digital readout Measurement Performance


• Relative Intensity Noise (RIN): −165 dB/Hz (laser RIN); −150 dBc/Hz system RIN on 1 mW laser


• Optical measurement accuracy: ±1 dB across full bandwidth


• Average power accuracy (factory calibrated): ±0.65 dB ±0.5 nW ±connector variation at 1300 nm, 1550 nm, or 830 nm


• Linewidth, chirp, and frequency modulation measurement of single-frequency lasers


• Modulation characterization: analog and digital formats on single-mode fiber

Key Features

• Broadband PIN photodiode with internal optical attenuator and electrical preamplifier


• RIN measurement routine removes receiver shot noise and thermal noise for accurate laser characterization


• Functions as electrical spectrum analyzer (100 kHz to 22 GHz)


• Optical power meter with visual analog bar and precision digital display (linear or logarithmic)


• Modular Measurement System (MMS) design for integration with additional modules

Typical Applications

• Laser RIN and intensity noise characterization


• Single-frequency laser linewidth and chirp measurement


• Optical modulator and detector evaluation


• Broadband signal analysis and modulation depth testing


• High-dynamic-range optical power measurement

Compatibility & Integration Designed as part of the Modular Measurement System (MMS), enabling expansion and integration with complementary modules for complex optical test scenarios. Compatible with Agilent 11980A fiber-optic interferometer for advanced linewidth measurements.