Electronic Design

Tester Characterizes Laser Diodes With 5-A Peak Pulses

The Model 2520 Pulsed Laser Diode Test System performs electrical characterization of laser diodes in either the chip/bar state or in finished products. According to its manufacturer, the 2520 is the only single-instrument system for testing laser diodes in pulse mode with up to a 5-A peak.

This instrument creates pulse widths as short as 500 ns with rise and fall times less than 60 ns. The laser diode is protected by output short and voltage compliance functions. In addition to its pulsed-current output, the 2520 features three measurement channels with a remote digitizing head connected by cables. While one channel measures voltage across the laser diode, two voltage-biased current measurement channels are employed for simultaneous measurement of the front and back photodiode detector outputs required to characterize edge-emitting lasers.

The Model 2520 is supplied in a half-rack-size box with IEEE-488 and RS-232 interfaces. Keithley says its single-box design increases the speed of setup and data collection. It enables complete light intensity-current-voltage (LIV) testing without the need for separate current-to-voltage converters, multichannel digital oscilloscopes, or customized software.

Also, its 14-bit analog-to-digital converter (ADC) ensures accurate determination of the laser diode's lasing threshold current, light-current (L-I) efficiency, and current-voltage (I-V) linearity. Manufacturers, then, can characterize the relationship between drive current and light output in the linear region above the lasing threshold.

Available now, the Model 2520 costs $18,000 for a single unit.

Keithley Instruments Inc., 28775 Aurora Rd., Cleveland, OH 44139-1891; (888) KEITHLEY; fax (440) 248-6168; www.keithley.com.

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