850 nm Optical Components for 25 Gb/s Optical Fiber Data Communication Links over 100 m at 85°C

We report on the development of 25Gb/s 850nm VCSEL and PD components for efficient short-reach optical fiber communication systems. VCSELs with the aperture size 6-7 mu m show the highest -3dB bandwidth (similar to 20GHz) and D-factor (similar to 8Ghz/mA(1/2)). K-factor is less than 0.25ns for VCSEL with 6 mu m aperture. Eye diagrams are clearly open at 25C up to 35Gb/s. The dark current of PDs remain below 1nA at T < 50 degrees C and below 10nA when T < 90 degrees C out to -10V. The extracted PD capacity is linearly proportional to the detector area and less than 200fF even for 45 mu m PD diameter. Due to elimination of contribution of diffusion process and quite small capacitance of the depletion region eye diagrams are opened at 28Gb/s, even for the PDs with the largest active diameters. Using 35 mu m PD and 6 mu m VCSEL error-free 25Gb/s optical fiber communication links were tested over lengths of 203m and 103m at 25 degrees C and 85 degrees C, respectively. Received optical power for the lowest BER is at both temperatures smaller than -4dBm. Obtained results indicate that from the speed and power dissipation perspective developed high-speed CSELs and PDs are suitable for applications in the next generation of short-reach multimode optical fiber interconnects.