Remote Operation

Remote instrument operation in an R&D or production environment is available through a USB or GPIB/IEEE-488 interface. A trigger output is provided for integration into an automated measurement system where the TTL level output indicates a current step change for initiation of a measurement. For virtual instrument programming, LabVIEW™ instrument drivers can be downloaded from the Literature & Downloads tab on this page.

High Stability, Low Noise Laser Control

Laser diodes act as a gain medium. Small drive current fluctuations due to noise and drift are amplified optically. Because of this, a controller with a low noise and stable output is required to ensure stable optical output. The LDC-3700C Series of controllers make this possible. Each LDC-3700C Controller offers a precision 16-bit current source with 0.05% accuracy. Careful attention to design delivers as low as 20 ppm stability and 1.5 µA of noise so component measurements can be made with confidence.

Setting the Standard in Laser Diode Protection

Laser diodes are extremely sensitive to electro-static discharge, excessive current levels, current spikes, or transients from power surges or other laboratory equipment. One of the most important features we have implemented into each instrument is the ILX Lightwave proven laser diode protection standards. These standards have led to advanced protection features such as adjustable compliance voltage limit, and fast output shut-off to limit device damage from intermittent contact. In addition, the current limit setting is independent of the voltage drop of the device connected to the laser output. Because the current limit circuitry is fully independent of the main current control, the current limit can be adjusted safely, even while the laser output is active. These protection features work in conjunction with all instrument modes of operation, providing worry free, fail safe control of your laser diode. For more information about these protection features, please see our “Protecting Your Laser Diode" application note.

A Choice of Laser Current Control Modes

Each laser diode driver’s laser current source can be operated in one of three modes:

  • Constant current, low bandwidth: optimized for DC operation and offers improved laser protection and lowest noise.
  • Constant current, high bandwidth: the output stage supports up to 1MHz modulation frequency for dithering the laser current in power and wavelength tuning applications.
  • Constant optical power: provides constant optical power operation of your laser diode by measuring the photocurrent from the laser diode’s rear-facet photodiode or an external photodiode in a feedback control loop to the current source.

Precision Temperature Control

The LDC-3700C Series Controllers include an integrated precision 32W temperature controller for quick temperature response of the laser diode’s chip temperature. For precise wavelength control during component testing, the LDC-3700C Series control algorithm maintains temperature with a stability of 0.004°C. Sixteen-bit control and measurement allows you to set temperature with 0.01°C resolution with a measurement accuracy of 0.05°C (with a calibrated sensor). In addition, the LDC-3700C series supports TEC forward voltage measurement for monitoring the total power consumption of your laser diode module.

Wide Temperature Control Range

These controllers offer extended temperature control from -100°C to 199.9°C with a choice of thermistor, IC, or RTD temperature sensors. Temperature can be controlled in one of three modes: constant temperature, constant sensor, or constant TE current. As an added precaution, if the temperature sensor or TE module circuit should open during operation, the laser diode current source output will be shut off and the appropriate fault indicator LED will illuminate. In addition to the normal control modes, the TEC output of the LDC-3700C Controllers is bounded by a fully independent hardware current limit to protect the laser diode’s internal TE module. These limits cannot be exceeded in any mode of operation. The controller can also be bounded by a high temperature limit setting.

Ease of Operation

Divided into two sections, TEC and LASER, the front panel offers quick, easy operation and information display without confusing multi-layer menus. Each bright, 5-digit, green LED display is easy to read from a distance, even with laser safety goggles. Each channel is directly addressable from the front panel "adjust" section with LASER and TEC parameters and modes easily selected or adjusted through discrete pushbuttons and a rotary digital encoder

Save and Recall Instrument Settings

For multiple instrument test configurations, the LDC-3700C Controllers offer a SAVE and RECALL feature. The SAVE function allows you to store all the front panel settings for any given instrument condition. The RECALL function allows you to retrieve any of the saved conditions at any time. This saves time in instrument re-configuration for different production runs or R&D experiments.