Keithley Introduces Flexible, Configurable Laser Diode Test Systems with Improved Performance and Cost

Cleveland, Ohio -- March 31, 2003 -- Keithley Instruments, Inc. (NYSE: KEI) has introduced fully customizable test system kits for light-current-voltage (LIV) characterization of laser diodes and assembled laser diode modules (LDMs). In the System 25, Keithley takes advantage of its proven LIV measuring instruments, combines them with unique accessories and cables, and supplies the complete package for less than individual components. Unlike "all-in-one" solutions, System 25 provides customers with the ability to choose only the features and performance they need. Moreover, System 25 kits reduce the time and cost of integrating measurement components into a production test system, and allow unmatched speed and measurement precision.

The Keithley System 25 provides up to 5A laser drive current, precision voltage measurements, two channels of photodetection, selectable photodiode detector types, optional laser diode mount, and up to two temperature controllers for laser cooling, all in an easy-to-assemble kit. The simple ordering process gives purchasers full flexibility in selecting only essential system components, thereby avoiding the cost of unnecessary items. Still, the System 25 can be easily modified as test needs change. It reduces the cost of testing for laser diode manufacturers, telecommunication system OEMs, and contract manufacturers, and lowers test system costs for integrators.

Application Background

Laser diodes capabilities and applications have grown beyond those originally found in fiberoptic telecommunications systems (e.g., transmitter and pump lasers). Now, applications include optical storage devices (based on blue laser technology), defense electronic systems, industrial printing, and a wide array of other uses. As laser diode capabilities have expanded, so have testing needs. The Keithley System 25 has the flexibility to keep up with these changing needs.

These efforts are driven by the potential for nanotechnology to be a US$1 trillion global industry in 10-15 years. Global research funding for nanotechnology is expected to exceed US$3 billion in 2003. More than 750 corporations and start-up companies, universities, and government labs around the world are actively working on applications as diverse as coatings, bioseparation, drug delivery systems, flat panel displays, and fuel cells.

All laser diodes, including edge emitters, vertical cavity surface emitting lasers (VCSELs), and tunable lasers, to name just a few, must undergo LIV testing. The test system sweeps a forward current through the laser diode while measuring the voltage across the device and the amount of light (optical power) being emitted. Typically, collected data are displayed as a series of LIV characteristic curves. These curves can be used in laser diode R&D and by production test engineers to review device parameters that determine if a laser diode or LDM is suitable for higher level assembly. In production facilities, these tests may be performed anywhere from incoming inspection to finished LDMs mounted in higher level assemblies.

Product Details

The Keithley System 25 was designed to simplify and reduce the cost of creating and using LIV test systems. It eliminates the need to purchase system components separately, which may include a source-measure unit, temperature controller, integrating sphere, photodiode detector, current meter, laser diode mount, plus cabling and ancillary hardware. A System 25 is easy to order and assemble, but provides the greatest flexibility of any LIV test system available. A system can be specified in any of 144 combinations that use Keithley Series 2400 SourceMeter® Instruments, Model 2502 Fiber Alignment Photodiode Meters, Model 2510-AT Autotuning TEC controllers, Model 2500INT Integrating Spheres, and Model 85xx Laser Diode Mounts.

These combinations are selected based on the application: general purpose laser diodes, transmitter/pump lasers, or high power pump lasers. For LDMs and laser diodes in cooled mounts, one or two TEC (thermoelectric cooler) controllers can be specified for the System 25. Typically, one Model 2510-AT will be used to control an internal TEC device; a second Model 2510-AT can be added to allow for precise control of ambient test temperature using a fixture mounted TEC. The Model 2500INT two-inch integrating sphere can be specified with either silicon, germanium, or cooled InGaAs photodetectors, depending on the wavelength response needed. For laser diodes packaged in the common 14-pin butterfly package or DIL package, a Keithley Model 85xx Laser Diode Mount can be used for easy connection of the device under test to the test equipment. The Model 8544-TEC mount has a built-in TEC cooler for ambient temperature control.

Customized variations of the System 25 are also available by contacting a local Keithley sales representative or the factory at the address listed below.

About Keithley Instruments. Keithley Instruments, Inc. provides optical and electrical measurement solutions from DC to RF (radio frequency) to the wireless, semiconductor, optoelectronics, and other electronics manufacturing industries. Engineers and scientists around the world use Keithley's advanced hardware and software for process monitoring, production test, and basic research.