The HP/Agilent 81491A Reference Transmitter is a high-performance electro-optical converter that generates accurate, low-jitter optical signals for advanced optical communication system testing. It produces high-quality eye diagrams for NRZ and PAM4 modulation formats at baud rates up to 32 Gbaud, with electro-optical bandwidth of 33 GHz and rise/fall times below 15 ps. The instrument delivers jitter performance of less than 1 ps RMS and supports stressed eye compliance testing per IEEE 802.3 standards. It operates with zero chirp modulation when paired with a clean external optical source, offering superior extinction ratio performance compared to directly modulated transmitters. The 81491A integrates directly into the Keysight Lightwave Measurement System platform for enhanced control and test bench scalability.
Technical Specifications
• Signal Types: NRZ, PAM4
• Baud Rates: Up to 32 Gbaud
• Electro-optical Bandwidth: 33 GHz (typical)
• Analog Modulation Bandwidth: 35 GHz
• Rise/Fall Times: < 15 ps (typical)
• Jitter: < 1 ps RMS and < 7 ps P-P (typical)
• TDEC (28 Gb/s NRZ): < 0.9 dB (typical)
• TDECQ (26.56125 Gbaud PAM4): < 1.2 dB (typical)
• Output Amplitude: 300 mV (option -085) or 600 mV (option -135)
– Key Features
• Zero chirp modulation with external optical sources
• Wide extinction ratio range exceeding directly modulated transmitter performance
• Multimode (850 nm) and single-mode (1310 nm, 1550 nm) laser options
• External optical input available for tunable laser sources and WDM applications (1260–1565 nm)
• SCPI remote control interface
• Storage temperature range: -40 °C to +70 °C (recommended: 10 °C to 40 °C for 81491A-085)
– Typical Applications
Optical receiver stress testing and compliance characterization for IEEE 802.3 10, 40, 100, and 400GBASE standards. Arbitrary optical modulation signal generation when combined with electrical arbitrary waveform generators.
– Compatibility & Integration
Full integration with Keysight Lightwave Measurement System mainframe platforms and Optical Receiver Stress Test solutions.
