%0 Journal Article
%T Advances in Red VCSEL Technology
%A Klein Johnson
%A Mary Hibbs-Brenner
%A William Hogan
%A Matthew Dummer
%J Advances in Optical Technologies
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/569379
%X Red VCSELs offer the benefits of improved performance and lower power consumption for medical and industrial sensing, faster printing and scanning, and lower cost, higher speed interconnects based upon plastic optical fiber (POF). However, materials challenges make it more difficult to achieve the desired performance than at the well-developed wavelength of 850£¿nm. This paper will describe the state of the art of red VCSEL performance and the results of development efforts to achieve improved output power and a broader temperature range of operation. It will also provide examples of the applications of red VCSELs and the benefits they offer. In addition, the packaging flexibility offered by VCSELs, and some examples of non-Hermetic package demonstrations will be discussed. Some of the red VCSEL performance demonstrations include output power of 14£¿mW CW at room temperature, a record maximum temperature of C for CW operation at an emission wavelength of 689£¿nm, time to 1% failure at room temperature of approximately 200,000 hours, lifetime in a C, 85% humidity environment in excess of 3500 hours, digital data rate of 3£¿Gbps, and peak pulsed array power of greater than 100£¿mW. 1. Introduction Multimode 850£¿nm VCSELs based upon the AlGaAs materials system have been the standard optical source for glass fiber optic-based data communication links since the mid-1990s. Although the first demonstration of red VCSELs followed fairly quickly after the demonstration of the industry standard ¡°all-semiconductor¡± 850£¿nm VCSEL, the commercialization of red VCSEL technology has proceeded much more slowly due to the materials limitations that have made the development more challenging. The AlGaAs materials system which is used for 850£¿nm VCSELs provides good lattice matching over the full range of compositions, a reasonably good refractive index contrast between the high index (AlGaAs with approximately 15¨C20% mole fraction AlAs) and low index (AlAs) materials used for the mirrors, and a high (approximately 0.35£¿eV) conduction band offset between the GaAs quantum wells and the AlGaAs compositions normally used as quantum well barriers. However, the 650¨C700£¿nm emission wavelength range requires use of GaInP quantum wells with AlGaInP barrier layers, with the compositions limited to those which are nearly lattice matched to a GaAs substrate. The AlGaAs materials system is usually used for the mirrors. Several limitations for these shorter wavelength VCSELs exist: (1) the available conduction band offset is smaller and ranges from approximately 0.17£¿eV at 650£¿nm to 0.23£¿eV
%U http://www.hindawi.com/journals/aot/2012/569379/