Attenuation of Vertical Cavity Surface Emitting Laser Optoelectronic Devices
Original Publication Date: 2001-Jul-15
Included in the Prior Art Database: 2003-Jun-20
Disclosed is a material that provides output attenuation from vertical cavity surface emitting laser (VCSEL) devices. Safety considerations dictate the permissible power output from VCSEL devices. In order to attenuate the laser output in the current designs, the polished ends of the optical fibers are vacuum coated with a thin metal layer. This additional process adds cost and reduces the reliability of the overall package. By incorporating a suitable near-IR dye into the encapsulant present in the optical gap between the VCSEL device and the coupling fibers, the level of attenuation can be tailored to meet the required safety guidelines. Typical VCSELs emit at 850 nm. In order to effectively attenuate the laser output, a dye possessing adequate absorption characteristics at 850 nm is incorporated into the encapsulant at the appropriate loading level. In addition to possessing an absorption peak or shoulder at 850 nm, the dye must also be transmissive at 350-400 nm so as not to interfere with the photoinitiator of the encapsulant. Several materials meeting these requirements are indicated below: Prussian Blue Rare Earth Halides Reaction Product of Phthalide Derivatives with Zinc Nitrobenzoates Near-IR Dyes An example of the utility of the concept is illustrated below using Prussian Blue as a non-inclusive representative of a suitable dye.