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We have demonstrated high density, 2D (4x12) VCSEL ar rays operating at an aggregate data rate of over 480Gb/s in an aerial density of 1400x3750 µ m 2 , or 9.14 Tbs/cm 2 . These flip-chip, bottom-emitting 990nm VCSELs have low drive voltage, low electrical parasitics, improved thermal impedance and 2D scalability over their wire-bonded top emitting counterparts. Excellent high speed performance was obtained through the use of 1) compressively strained InGaAs MQW active region 2) low parasitic capacitance oxide-confined VCSEL structures and 3) low series resistance, high index contrast AlGaAs/GaAs mirrors. 10Gb/s operation was obtain ed with low operating current density of ~6kA/cm 2 at 70 o C. Our best results to date have achieved data rates greater than 15Gb/s @70 C at a current density less than 10kA/cm 2 . The device results show good agreement with theoretically calculated/simulated values. 1. INTRODUCTION Future rack-to-rack and board-to-board computer interconnects will require data rates in excess of 20Gb/s while maintaining the smallest aerial density and low power consumption. 990nm VCSELs exhibit better high speed performance, improved thermal behavior an d the advantage of flip-chip 2D arrays over their 850nm counterparts. 990nm VCSELs have improved carrier confinement resulting from a higher conduction band offset, improved differential gain and lower transparency due to strain [1] and low optical attenuation through the GaAs substrate. The use of higher contrast (compared to 850nm) AlGaAs DBRs improves the mode volume and thermal resistan ce of these devices. The use of AlGaAs DBRs on GaAs substrates in these VCSELs allows robust epi and device process window and lends itself to manufacturability. 2. METHODOLOGY Epitaxial growths were performed by low pressure metalorganic chemical vapor deposition (MOCVD), in a production scale reactor with arsine, trimethyl- group III alkyl precursors, and disilane (0.01% in H |
