Static and dynamic characteristics of double transverse coupled cavity VCSELs for high speed modulations

We present experimental results for extending the 3-dB modulation bandwidth of an 850-nm vertical-cavity surface-emitting laser (VCSEL) with passive double transverse-coupled cavities (DTCC). The 3-dB modulation bandwidth of DTCC-VCSEL is 21 GHz while that of a conventional VCSEL (C-VCSEL) fabricated in the same wafer is 12 GHz. We realize eye-opening at large-signal modulations of 36 Gbps (NRZ) and 44 Gbps (PAM4). Intensity fluctuations of single-transverse-coupled cavity (STCC)-VCSEL and DTCC-VCSEL were also examined at different bias currents under CW operations. The result shows a DTCC-VCSEL is more stable with lower intensity fluctuations.