Novel optical fibers for data center applications

1030 nm multilayer oxide aperture VCSELs with 25 GHz modulation bandwidth and 40 Gb/s NRZ transmission

“…However, the distance is fundamentally limited by the high chromatic dispersion of fiber and attenuation at this wavelength [4,5]. At 850 nm, the fiber chromatic dispersion is as high as~85 ps/nm/km and the attenuation exceeds 2 dB/km [6,7]. With data centers growing in size, the increased demand for longer reach optical interconnects (up to 2 km in large scale data centers [5]) drives the development of longer wavelength VCSELs so that the reach limitations of the 850 nm multimode links can be overcome.…”

“…However, the GaAs-based VCSEL technology, which is superior to the InP-based in terms of speed, efficiency, manufacturability and cost-efficiency, can only be extended to∼1100 nm using conventional compound semiconductors without compromising reliability [11]. This has created an interest in GaAs-based VCSELs at wavelengths just below 1100 nm where the fiber chromatic dispersion is~30 ps/nm/km and the attenuation is below 1 dB/km [6,7]. a large improvement with respect to 850 nm.…”

Pre‐emphasis enabled 50 Gbit/s transmission over 1000 m SMF using a 1060 nm single‐mode VCSEL

“…Transitioning from 850 to 1060 nm leads to a 50% reduction of fibre attenuation and a 70% reduction of chromatic dispersion [7]. This has led to demonstrations of MMF links with capacities of 25 Gbit/s NRZ‐OOK over 1000 m [8] and 50 Gbit/s 4‐PAM over 310 m [9].…”

1060 nm single‐mode vertical‐cavity surface‐emitting laser operating at 50 Gbit/s data rate

“…When using multimode VCSELs, reach is limited by chromatic dispersion at high data rates. At a longer wavelength, such as 1060 nm, chromatic dispersion is reduced by a factor of three and attenuation is reduced by more than a factor of two [2]. This has enabled transmission at 25.78 Gbit/s on–off keying (OOK) over 1 km of MMF optimised for high modal bandwidth at 1060 nm using a 20 GHz 1060 nm multimode VCSEL [4].…”

“…Introduction: Optical interconnects used in datacentres are dominated by 850 nm GaAs-based vertical-cavity surface-emitting laser (VCSEL) and multimode fibre (MMF) links with reach up to ∼100 m at high data rates [1]. With large-scale datacentres requiring reach up to 2 km, VCSEL-MMF links at longer wavelengths are of interest because of reduced chromatic dispersion and attenuation in the MMF [2]. GaAs-based VCSELs are still preferred because of their superior modulation speed, efficiency, and manufacturability and it has been demonstrated that the wavelength can be extended to ∼1100 nm without compromising reliability [3].…”