Development of high-speed VCSELs beyond 10 Gb/s at Emcore

Abstract

We report developments at Emcore on serial 850 nm vertical-cavity surface-emitting lasers (VCSELs) operated up to 25 Gb/s. They have been designed to provide a solution not only to meet stringent 10 Gb/s IEEE and Fiber Channel specifications but also for emerging demands of 17 Gb/s Fiber Channel serial and 100 Gb/s (4x25 Gb/s or 5x20 Gb/s) parallel applications in local and storage area networks. This paper covers 10 Gb/s GenX production distributions and improved GenX VCSEL device design to meet low-power requirements at 20 Gb/s. We have successfully demonstrated low threshold current of 0.65 mA at 25°C using nominal 7.3 μm oxide-aperture GenX VCSELs. They can be directly modulated up to 25 Gb/s with open eyes at 6 mA bias. With the same design, open eyes of 20 Gb/s is achieved at bias current as low as 4 mA (9 KA/cm 2 ) at 25°C and 8 mA (18 KA/cm 2 ) at 70°C. These operation conditions are comparable to current 10 Gb/s GenX VCSELs in production which have been shown a great field history.