The VCSEL I-V Test Subsystem requires system compensation and pulse compensation before the subsystem can perform I-V measurements on VCSEL DUTs. System and pulse compensation gathers data about subsystem components and pulse settings to characterize subsystem performance and ensure accurate I-V measurements during test execution.
System compensation characterizes subsystem components, including the NI-4134 pulse generator, the PXIe-5162 oscilloscope, attenuators, and the BNC cables that connect these components to the load board. Perform system compensation if any connections within the VCSEL I-V Test Subsystem change, such as a cable replacement, or if the facility environment exceeds the environmental specifications for the subsystem.
Pulse compensation characterizes the specified pulse train with an open circuit, a shorted circuit, and a known-good DUT circuit. Then, the subsystem uses the compensation data to adjust the voltage output of the PXIe-4135 SMU in order to generate a pulse with the specified current amplitude.
Perform pulse compensation after any changes to the settings for the pulse measurements that the VCSEL I-V Test Subsystem executes or after any changes to the subsystem mode of operation. You can use the VCSEL I-V Test Software to perform system compensation and pulse compensation.