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Ultra-broadband Superluminescent Diodes

Praevium Research, under funding from the National Institutes of Health, has developed 1300nm superluminescent diodes with a combination of high power and broad optical bandwidth.  These advances have been enabled by fundamental materials and gain region design innovations. Soon to be released commercial devices provide >10 mW fiber- coupled power in conjunction with >115 nm bandwidth. Praevium has also developed proprietary wafer bonding approaches to single-chip integration of multiple gain regions. Integration of two gain regions on a single chip has demonstrated ~200nm bandwidth. Praevium’s emerging commercial ultra-broadband devices offer ~200nm bandwidth in conjunction with >10 mW power through external combining of two broadband SLEDs.

Multi-Wavelength Laser Arrays for Spectroscopy

Near Infrared Spectroscopy has traditionally been accomplished using filtered white light sources and rotating gratings or detector arrays. This approach suffers from limited signal to noise ratio, high power consumption, and optical complexity. Praevium, under funding from the US department of Agriculture and the National Institutes of Health, has developed miniaturized multi-wavelength laser arrays that offer essentially tunable radiation covering critical portions of the vis/NIR range (650-2100nm), at the output of a multi-mode optical fiber. Such sources have dramaticallly increased signal to noise ratio relative to filtered white light, particularly in applications where high spatial resolution is required. Additionally, lasers can be high-speed modulated to obtain frequency domain as well as steady state measurements. Laser wavelengths can be customized to target a wide variety of specific applications, such as breast cancer detection, assessment of body hydration status, or quantification of agricultural constituents.

 Wafer Bonding

Praevium scientists contributed to much of the early work on planar wafer bonding of GaAs to InP, which was driven in large part by the development of long-wavelength vertical cavity lasers. This work demonstrated atomically continuous GaAs/InP interfaces, low voltage current injection across such interfaces, and reliable, high power wafer-bonded VCSEL operation. In recent years Praevium has developed a unique proprietary process for lateral wafer bonding of dissimilar semiconductors along cleaved facets, with excellent waveguide alignment.  GaAs/GaAs, InP/InP, and InP/GaAs bonded interfaces have been demonstrated. A number of devices, such as ultra-broadband superluminescent diodes and CWDM arrays have been demonstrated using this new technology. Further Information.