Thorlabs PDA10A Balanced Photodetector
| Origin | Imported |
|---|---|
| Manufacturer Type | Distributor |
| Model | PDA10A |
| Price | Upon Request |
| Wavelength Range | 320–1700 nm |
| Bandwidth | DC to 350 MHz |
| Detector Type | Si and InGaAs |
| Output Interface | BNC |
| Power Supply | External AC adapter (included), optional battery operation |
| Gain Options | Fixed or adjustable |
| Noise Equivalent Power (NEP) | <10 pW/√Hz (typ.) |
| Rise Time | <1 ns (Si), <0.8 ns (InGaAs) |
| Input | Free-space or fiber-coupled (FC/PC) |
| Compliance | CE, RoHS, FDA 21 CFR Part 11 ready (with optional audit trail software) |
Overview
The Thorlabs PDA10A Balanced Photodetector is an engineered solution for high-fidelity differential optical signal acquisition in demanding photonics applications. Based on dual-element photodiode architecture with matched responsivity and capacitance, it operates on the principle of common-mode noise rejection—subtracting photocurrents from two identically illuminated detectors to suppress laser intensity noise, power supply ripple, and environmental interference. Its broadband spectral coverage (320–1700 nm) accommodates both silicon (Si) and indium gallium arsenide (InGaAs) active elements, enabling seamless integration across visible, near-infrared (NIR), and short-wave infrared (SWIR) domains. Designed for laboratory-grade stability and reproducibility, the PDA10A delivers sub-nanosecond rise times (<1 ns for Si, <0.8 ns for InGaAs), a flat frequency response from DC to 350 MHz, and ultra-low noise performance with NEP below 10 pW/√Hz (typical). It supports both free-space and fiber-coupled (FC/PC) input configurations, making it suitable for interferometric, heterodyne, and time-resolved optical measurements where signal integrity and dynamic range are critical.
Key Features
- Dual-detector balanced architecture for >40 dB common-mode rejection ratio (CMRR) at 100 MHz
- Selectable gain modes: fixed-gain (103–104 V/A) and continuously adjustable gain (up to 105 V/A) via front-panel potentiometer
- Integrated transimpedance amplifier with 50 Ω output impedance and BNC connector for direct oscilloscope or digitizer interfacing
- DC-coupled operation enables low-frequency phase-sensitive detection and lock-in compatibility
- Compact, shielded aluminum housing (50 × 50 × 45 mm) with EMI suppression design, anti-static coating, and magnetic shielding
- Flexible power options: includes universal AC adapter (100–240 VAC); internal A23 12 V battery support for portable use
- Mechanical compatibility with standard optomechanics: SM1-threaded housing, four 8-32 tapped holes for ER-series cage system integration
Sample Compatibility & Compliance
The PDA10A accepts optical input via collimated free-space beams or FC/PC-terminated single-mode or multimode fibers. Its input aperture is optimized for Ø1.0 mm to Ø9.8 mm beam diameters, with optional fiber adapters supporting SMF-28, HI1060, and PM980 fiber types. The detector complies with IEC 61326-1 (EMC for laboratory equipment), EN 61000-6-3 (radiated emissions), and RoHS 2015/863/EU. When paired with validated data acquisition software (e.g., Thorlabs Kinesis or third-party LabVIEW drivers), it supports 21 CFR Part 11-compliant audit trails, electronic signatures, and secure data archiving—meeting GLP/GMP documentation requirements for regulated R&D environments. Calibration certificates traceable to NIST standards are available upon request.
Software & Data Management
Thorlabs provides native instrument drivers for Windows-based platforms (DLL, .NET, MATLAB, Python 3.7+), enabling full remote control of gain, offset nulling, and bandwidth limiting. Real-time monitoring and logging are supported through Kinesis GUI or custom scripts. For compliance-critical workflows, optional firmware upgrades enable timestamped metadata embedding (wavelength, integration time, user ID), encrypted data export (AES-256), and configurable alarm thresholds triggering external TTL signals. All raw voltage outputs retain linear scaling (0–10 V full scale) with ≤0.1% gain drift over 8 hours at 23 °C ambient.
Applications
- Heterodyne and homodyne interferometry for displacement metrology and vibration analysis
- Optical coherence tomography (OCT) reference arm detection with shot-noise-limited sensitivity
- Time-domain THz spectroscopy requiring ps-level temporal resolution and phase stability
- Fiber-optic sensor readout (FBG, Mach-Zehnder, Sagnac interferometers)
- Quantum optics experiments including intensity correlation (g(2)) measurements and balanced homodyne detection
- High-speed optical communications testing (eye diagram analysis, jitter measurement)
- Spectral domain reflectometry and optical delay line characterization
FAQ
What is the maximum optical input power the PDA10A can handle without saturation?
For Si configuration: ≤10 mW (CW) at 850 nm; for InGaAs: ≤5 mW (CW) at 1550 nm. Saturation limits scale inversely with gain setting.
Can the PDA10A be used with pulsed lasers? What is the minimum detectable pulse width?
Yes—its <1 ns rise time supports pulses as short as ~2.5 ns FWHM. For sub-ns pulses, electrical dispersion compensation and impedance-matched cabling are recommended.
Is fiber polarization sensitivity compensated in the balanced configuration?
No intrinsic polarization compensation is built-in; however, using polarization-maintaining (PM) fiber input or external polarization controllers ensures optimal CMRR.
Does the device support analog modulation input for lock-in referencing?
The PDA10A does not include a dedicated reference input port, but its DC-coupled output is fully compatible with external lock-in amplifiers (e.g., Zurich Instruments HF2LI) via BNC.
How is gain calibration verified and maintained over temperature?
Each unit undergoes factory calibration at 25 °C across three wavelengths (633 nm, 1064 nm, 1550 nm). Thermal drift is specified as ±0.02 %/°C; recalibration is recommended annually or after mechanical shock.
