Keithley 2502 Dual-Channel Picoammeter

The Model 2502 is also designed to increase the throughput of Keithley’s LIV (lightcurrent-voltage) test system for production testing of laser diode modules (LDMs). Developed in close cooperation with leading manufacturers of LDMs for fiberoptic telecommunication networks, this dual-channel instrument has features that make it easy to synchronize with other system elements for tight control over optical power measurements. The Model 2502
features a high speed analog output that allows using the LIV test system at the fiber alignment stage of the LDM manufacturing process.

Through the use of buffer memory and a Trigger Link interface that’s unique to Keithley instruments, the Model 2502 can offer the fastest throughput available today for LIV testing of laser diode modules. These instruments are ruggedly engineered to meet the reliability and repeatability demands of continuous operation in round-the-clock production environments.

Key Featues:

• Dual-channel instrument for optical power measurements, beam measurements, and nanoscale materials and device research
• ±100V source for bias requirements
• Measure photodetector current from 1fA to 20mA
• 1fA current measurement resolution
• Measure optical power directly when used with Model 2500INT Integrating Sphere
• 0–10V analog output for high resolution optical power feedback
• Provides a high accuracy, high speed fiber alignment solution
• Supports assembly process, final testing, parts binning, and specification
• Allows faster alignment of the fiber with the laser diode’s optimum light emitting region
• Combines fiber alignment and device characterization processes
• User-programmable photodetector calibration coefficients
• 3000-point buffer memory on each channel allows data transfer after test completion
• Digital I/O and Trigger Link for binning and sweep test operations
• IEEE-488 and RS -232 interfaces

Low-Level, High Speed Measurements

The Model 2502 combines Keithley’s expertise in low-level current measurements with high speed current measurement capabilities. Each channel of this instrument consists of a voltage source paired with a high speed picoammeter. Each of the two channels has an independent picoammeter and voltage source with measurements made simultaneously across both channels.

Part of a High Speed LIV Test System

In a laser diode module DC/CW test stand, the Model 2502 provides the voltage bias to both the back facet monitor diode and a Model 2500INT Integrating Sphere or to a fiber-coupled photodetector. At the same time it applies the voltage biases, it measures the current outputs of the two photodetectors and converts these outputs to measurements of optical power. The conversion is performed with the user-programmed calibration coefficient for the wavelength of the laser diode module. Fast, accurate measurements of optical power are critical for analyzing the coupling efficiency and optical power characteristics of the laser diode being tested. When testing modules with multiple detectors, the Model 2502 packs more testing capabilities into less test rack space.

Read the datasheet to find out more.