FAQ1164

Answer

Superluminescent diodes (SLDs) are light sources that combine the output power of a laser diode (LD) with the broad emission spectrum of a light emitting diode (LED). The emission of SLDs is coherent enough to be coupled into fibers, and they are available in the same packaging styles as LDs (TO Cans, Dual-In-Line, and 14-pin butterfly).

SLDs generally require a low amount of current, and a small voltage for operation. The low-current models that are commercially available require hundreds of milliAmps, with less than 5 V required for emission. High-current models can require on the order of 1 A of current with the same voltage requirements.

Similar to laser diodes, SLDs are extremely sensitive to noisy current, as well as temperature fluctuations. The level of current that is driven through the SLD is one of the main factors affecting the lifetime of SLDs. Noisy current can have a negative impact of the life of SLDs by inadvertently driving more current than is wanted. The semiconductor gain medium in SLDs is highly temperature dependent. As the temperature of the SLD goes up, the gain goes down. Thus, proper operation of SLDs requires a low-noise current source, as well as a stable temperature controller.

SLDs are available in a wide range of center wavelengths, along with large variation in the full-width at half maximum (FWHM) of emission. Power outputs range from approximately 0.1 mW up to 50 mW.

Wavelength Electronics offers low-noise drivers to supply the current and voltage to the superluminescent diode.

SLD DRIVER	DIODE CURRENT AVAILABLE	DATASHEET
LDD200P	up to 200 mA
PLD200	up to 200 mA
MPL250	up to 250 mA
LDD400P	up to 400 mA
FL500	up to 500 mA
PLD500	up to 500 mA
MPL500	up to 500 mA
LDTC0520	up to 500 mA
LDTC1020	up to 1 A
PLD1250	up to 1.25 A

For those packaging types (Dual-In-Line and 14-pin butterfly) that have integrated thermoelectric coolers, temperature controllers are also available that offer best-in-class stability.

TEMPERATURE CONTROLLER	TEC CURRENT AVAILABLE	DATASHEET
HTC1500	up to 1.5 A
PID1500	up to 1.5 A
WTC3293-14001 WTC32ND-14	up to 2 A
LDTC0520	up to 2.2 A
LDTC1020	up to 2.2 A

Note that the LDTC family of products (LDTC0520 and LDTC1020) are units that combine a laser driver, and a temperature controller into one package. This eliminates the need for a separate SLD driver and temperature controller.

For SLDs that come in the 14-pin butterfly package, the LDMOUNT is available for simple mounting and connectivity. With one 9-pin DSUB connection for the SLD driver and another for the thermoelectric controller (TEC), along with a safety interlock circuit and a TEC Active/Bypass switch, the LDMOUNT allows SLDs to be operated with ease. A zero-insertion-force (ZIF) socket makes mounting the SLD hassle-free.

If the SLD being used has higher current or voltage requirements, Wavelength offers drivers and temperature controllers with greater output. For questions regarding setup, operation, or troubleshooting, contact Wavelength Technical Support (techsupport@www.teamwavelength.com).