What are the advantages and disadvantages?
Decisive features of the surface emitter lasers (compared to edge emitting lasers) are the lower production costs and the better beam quality – however with a lower output power. The coupling efficiency in optical fibers is high due to the small footprint, the good beam quality and the good focusability. As an SMT (surface-mountable component), a VCSEL combines characteristics of an LED with those of a laser and is easier to assemble than an EEL (edge emitting laser). It offers coherent light with directed emission, the higher power density and simple packaging of an IRED, but has the spectral width of a line emitter, like EEL or DFB (distributed feedback laser diodes) technology. The beam shape of a VCSEL is a circular spot, compared to the elliptical shape of FP-EEL (Fabry-Perot Edge Emitting Laser) and DFB. Unlike the temperature sensitive wavelength of an EEL, VCSEL suffer way less wavelength shift under the influence temperature changes.
The main advantages of the different IR technologies can be summarized as follows:
- VCSEL: cost effective chip, narrow divergence, high efficiency
- EEL: High performance, very high efficiency, high luminance
- IRED: homogeneity of lighting, very cost effective chip, wide range of different models
