SL5.3 8 x 6 Wavelength-Tunable Vertical Cavity Surface-Emitting Arrays

We report a novel individually addressable, individually wavelength tunable 8 x 6 vertical cavity surface-emitting laser (VCSEL) array. A two-dimensional array of individually wave-length-tunable VCSELs is very attractive for free-space optical interconnect in massively parallel computers [ 1-21. VCSEL’s have large mode spacing due to the very short cavity and are particu-larly suitable for continuous wavelength tuning. In addition, the low threshold currents, low beam divergence angles, and their ability to form two-dimensional arrays make them attractive for free-space optical interconnect applications. A two-dimensional array of fixed-tuned multiple wavelength VCSEL array [3] and a three-terminal VCSEL with continuous wavelength tuning [4] have been reported. In the latter, a continuous tuning range of 2.2 nm is obtained, however, it involves more complicated processing steps. In this paper, we demonstrate a continuously tun-able, individually addressable 8 x 6 VCSEL array using integrated heaters. VCSEL’s with a mesa size of 12 pm x 12 pm exhibit a threshold current of 4.2 mA, output power of 1.2 mW (cw, room temperature), and continuous tuning range of 10 nm are obtained. Because VCSEL’s are localized in areas, wavelength tuning with integrated heaters is very effective. Integrated heaters were used in edge-emitting distributed feedback and Bragg reflecto