Vertical Cavity Surface Emitting Lasers for 1550 nm Wavelength Division Marketing

Vertical Cavity Surface Emitting Lasers (VCSELs) are highly promising for applications to communication and data networks because of lower cost and coupling efficiency to single mode fibers. However, development of these devices for telecommunication-wavelength (1550 nm) has been very difficult so far since the small index difference between InP/InGaAsP (~0.2) quarter-wave stack Bragg mirrors requires a large number of layers which (a) pose significant resistive losses, (b) low Q cavity and high threshold current and (c) narrow mirror spectral response making the devices difficult to grow and highly temperature sensitive. Alternative approaches using SbGaAsAI/InGaAsP materials systems and wafer fusion of InGaAsP with GaAs/AlOx Bragg mirrors currently carry the burden of poor reliability and yield. CoreTek proposes a novel solution to developing 1550nm VCSELs with tuning capability over the range of erbium doped fiber amplifier gain region. The method relies on post deposition of a broad band mirror using Plasma Enhanced CVD and substrate removal technique. The proposed structures will lend themselves to fabrication of microelectromechanical tunability allowing agile tuning well over 100nm. In Phase I we will demonstrate optically pumped version of the device and separately the tuning mechanism. Full fabrication of electrically pumped lasers will be performed in Phase II. Multimedia, internet and faster computers are making it easier and faster to transfer and access more information over the fiber from point to point. Wavelength division multiplexing is becoming the next technology whose implementation will significantly improve the flexibility and data throughput in future fiberoptic networks. The proposed program will result in cost effective broadly tunable transmitting lasers and receiver filters which are key components in such network.