Thorlabs FPD310-FC-NIR – InGaAs Fiber-Coupled Amplified Photodetector, Switchable Gain, 950-1650 nm

The Thorlabs FPD310-FC-NIR is an amplified photodetector module built around an InGaAs PIN diode, designed for high-speed, low-light-level detection in the near-infrared spectral range (950–1650 nm). It features a fiber-coupled SMF-28 pigtail terminated with an FC/APC connector, an integrated RF amplifier with switchable gain, and an SMA output for coupling to scopes, spectrum analyzers or other RF equipment.

Key Specifications & Features:

• Wavelength range: 950 nm to 1650 nm.

• Fiber-coupled input: SMF-28 pigtail with FC/APC connector.

• Switchable gain: Two fixed gain settings allow the user to trade off between higher sensitivity vs higher bandwidth.

• High bandwidth: Typical frequency range 1 MHz up to ~1.5 GHz (3 dB bandwidth) depending on gain setting.

• Fast rise time: ~0.5 ns in switching-gain high-bandwidth mode.

• Low noise performance: Noise equivalent power (NEP) ~12 pW/√Hz under certain operating conditions.

• Output: SMA female connector, 50 Ω output impedance recommended.

• Power supply included: Universal AC input (as per product family) and mounting provision (M4 tapped hole) for optical-bench integration.

• Saturation / damage thresholds: < ~200 µW saturation (CW) and ~2 mW damage threshold (for pulsed/fiber input) – check datasheet for exact values.

Applications:
Ideal for:

• Detection of fast laser pulses in the near-IR, e.g., mode-locked lasers, telecom lasers.

• Optical beat-note detection (heterodyne/homodyne) in photonics/metrology systems requiring high sensitivity and bandwidth.

• Low-light level signal extraction, RF and pulse-shape extraction from optical sources.

• OEM integration due to compact fiber-coupled module design.