Recently, a cooperation team of Russian research institute and Bimberg Chinese-German Center for Green Photonics, Changchun Institute of Optics, Fine Mechanics and Physics (CIOMP) of the Chinese Academy of Sciences (CAS), have successfully realized high-speed SM 1550 nm wafer fused (WF) VCSELs.
The infrastructure of more recent data centers is emerging to a coexistence between multimode fibers and single-mode fibers (SMFs) enabling WDM (Wavelength-Division Multiplexing) solutions. Thus, both larger capacity and longer reach is achieved as the data centers grow in both size and traffic. Long-wavelength (LW) single-mode (SM) VCSELs reduce the negative effect of modal and chromatic dispersion in an optical link.
1550 nm VCSELs are promising for next generation giga data centers, where optical links based on SM fibers with longer transmission distances are important, in particular for wavelength WDM. Therefore, 1550 nm SM VCSELs show a great potential for next-generation short-reach optical interconnects.
In this work, the continuous-wave (CW) and dynamic characteristics of 1550 nm SM VCSELs, fabricated by direct bonding of MBE-grown wafers were reported. Usage of optimized both structure design with active region based on thin strained InGaAs/InAlGaAs quantum wells (QWs) as well as VCSEL device topology allowed to enhance the -3dB modulation bandwidth up to 13 GHz and demonstrate 37 Gb/s non-return-to-zero (NRZ) direct modulation at room temperature, which is the largest date rate for 1550 nm WF VCSELs until now to the best of our knowledge.
In addition, the large output optical power and dynamic characteristics of studied 1550 nm InGaAs QW-based WF VCSELs indicate their potential for large distance transmission (e.g. 1 km), where a high bit rate keeping SM behavior is necessary in order to operate narrow WDM systems (e.g. 5 nm distance).
Further increase of modulation performance can be related with decrease the parasitic capacitance as well as photon lifetime adjustment.
The above work was published inIEEE Photonics Technology Letters. The corresponding authors are Andrey Babichev and Tian. Sicong. The work is supported by Chinese Academy of Sciences (CAS) President’s International Fellowship Initiative (PIFI) of 2021FST0002, 2023VTA0007, and 2023VTB0002.
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