New Focus 1811

The New Focus 1811 is a DC-coupled InGaAs/PIN photoreceiver engineered for precision near-infrared optical measurements. It delivers high sensitivity across the 900–1700 nm band with a 3 dB bandwidth of 125 MHz, 3 ns rise time, and minimum noise-equivalent power of 2.5 pW/√Hz. The device combines a maximum conversion gain of 4 × 10⁴ V/W with typical responsivity of 1.0 A/W at 1550 nm, making it well-suited for fiber-optic sensors, optical metrology, and high-resolution spectroscopy where fast signal transients and low-noise performance are critical. Available with detector diameters of 0.1 mm, 0.15 mm, or 0.3 mm, the 1811 accepts optical input via FC connector (singlemode or multimode fiber) or free-space coupling. Its 50 Ω output impedance and SMA electrical connector integrate directly into standard RF measurement chains. AC-coupled versions provide selectable bandwidth from 25 kHz to 125 MHz with integrated DC bias monitoring. Comprehensive RF shielding and filtered power-supply inputs suppress electromagnetic interference. The unit operates on ±15 V DC at under 250 mA and maintains temperature stability across 10–35 °C. Maximum CW saturation power reaches 55 µW at 1550 nm; pulsed signals handle up to 5 mW. An external ±15 VDC power supply (sold separately) is required. The photoreceiver ships with M4 thread adapter and mounting tool.