SBIR-STTR Award

This Small Business Innovation Research Phase I project will evaluate the feasibility of significantly improving the output power, temperature range of operation, and reliability of red VCSELs. The objective of the Phase I project is to develop a design approach for 650-680nm VCSELs that will increase the temperature range of operation by >20 deg C, improve the output power by greater than 30% and improve lifetime at 50 deg C to 3000 hours. The Phase I work will also provide the insight for even more substantial performance improvements for further developments. This project will use existing epitaxial wafers to test a novel fabrication approach for improving carrier injection and remove heat from the devices. This proposed work will enhance the understanding of the design features impacting the high temperature performance of red VCSELs. If the objectives are achieved, the activity will significantly improve the performance of red VCSELs relevant to commercially important applications. In addition to a more comprehensive understanding of the impact of the design parameters, the prediction of the limits of the technology will be estimated and modified. An understanding of the parameters affecting device reliability will also be developed. The approach proposed for this Phase I program breaks out of the traditional model for fabricating VCSELs, by implementing a hybrid integration approach that can impact the fundamental issues limiting the technology. If successful, the results will open up a wide range of commercial opportunities that would benefit from the performance characteristics of VCSELs, including plastic optical fiber for homes and automobiles, laser printing, industrial sensing, military LIDAR, and medical sensing. To date, the only commercially available VCSELs have been in the wavelength range of 780nm to 850nm, due to the materials challenges existing of devices outside this range. The proposed work may be applicable to a variety of VCSEL wavelengths (similar thermal issues exist on the long wavelength side, i.e. 1310nm to 1550nm), as well as other optoelectronic devices that may be limited by thermal issues. Commercially, a significant enhancement in red VCSEL performance can enable the migration of plastic fiber based home and auto networks to higher data rates (Gbps vs Mbps), can enable faster and higher quality laser printing, can facilitate longer distance and more precise motion control sensing, and enable new types of portable or wearable medical sensing that uses spectroscopic absorption or fluorescence for detection. The ability to bring this additional value to these applications in turn opens up a significant business opportunity for the suppliers of red VCSELs. The project also has an educational component, in that a student intern will assist on the project, and will develop an improved understanding of the technology, as well as exposure to the process of transferring technology to drive a business activity

This Small Business Innovation Research (SBIR) Phase II project will demonstrate significantly improved output power, temperature range of operation, and reliability of red VCSELs. Commercialization of red VCSEL technology has been plagued by the limited temperature range and output power of the devices and unknown reliability characteristics. The Phase I project demonstrated the 1) feasibility of improving output power and temperature range through a number of techniques, 2) that the fundamental limit of the temperature range is at least as high as 125°C, and 3) dramatically improved reliability. The Phase II approach proposed here breaks away from traditional models for fabricating VCSELs and consists of a variety of growth and fabrication methods allowing us to provide a high thermal conductivity path from the active region to the package. The goals and expected technical results are to demonstrate > 0.5mW single mode, and >1mW multi-mode useful output power at 670nm at 85°C, and the same power output power objectives for 655nm at 65°C on a reproducible basis. This project will also demonstrate greater than 10,000 hours device lifetime at 85°C continuous operation. Project activities consist of design, wafer growth and fabrication, performance testing, and reliability testing. To date, the only commercially available VCSELs have been at 780nm to 850nm, due to the substantial materials challenges at other wavelengths. This proposed effort is applicable to a variety of VCSEL wavelengths (similar thermal issues exist at 1310nm to 1550nm), as well as other optoelectronic devices. Commercially, a significant enhancement in red VCSEL performance can enable the migration of plastic fiber based home and auto networks to higher data rates, faster and higher quality laser printing, longer distance and more precise motion control sensing, new types of portable or wearable medical sensing, and improved robustness and cost of radiography equipment. The success of this project not only creates a significant business opportunity for a red VCSEL supplier, but also enhances the competitiveness of customers by making available a valuable new technology. The reduction in power consumption and improvement in medical technology costs address particularly important societal issues