High-Speed 850-nm VCSELs Operating Error-Free Beyond 50 Gbit/s
Conference poster, 2013
The 850-nm vertical-cavity surface-emitting laser (VCSEL) is a key component in today’s short reach (<100 m) optical interconnects due to low-cost fabrication, excellent high-speed properties at low drive currents, and the availability of high-speed multimode fiber (MMF) optimized for 850 nm. To meet the growing needs in data centers, near future datacom standards will require VCSELs operating well beyond the ~20 Gbit/s which today’s commercially available components are capable of.
Through reduction of the electrical parasitics, improvement of the optical confinement, and optimization of the photon lifetime, we recently demonstrated a small-signal bandwidth of 28 GHz for a ~4 µm oxide aperture VCSEL. Using a VCSEL with a larger oxide aperture (~7 µm) and a 30 GHz photoreceiver with an integrated limiting amplifier (VI-systems R40-850) enabled error-free [bit error rate (BER) <10-12] transmission up to 47 Gbit/s back-to-back (BTB) and 44 Gbit/s over 50 m OM4 fiber. Error-free transmission up to 40 Gbit/s was demonstrated BTB at temperatures up to 85°C. By employing a 22 GHz photoreceiver with an integrated linear amplifier (New Focus 1484-A-50), an ~8 µm oxide aperture VCSEL could operate error-free up to 57 Gbit/s BTB, 55 Gbit/s over 50 m, and 43 Gbit/s over 100 m OM4 fiber. These results represent a significant progress of current state-of-the-art in VCSEL performance.