40 GHz Bandwidth and 64 GHz Resonance Frequency in Injection-Locked 1.55$$\backslash$mu $ m VCSELs

Injection locking is shown to greatly enhance the resonance frequency of 1.55 μm vertical-cavity surface-emitting lasers (VCSELs), from 10 to 60 GHz, under ultrahigh injection locking conditions. Using injection locking to increase the laser resonance frequency, together with a low parasitic VCSEL design, a 3 dB bandwidth of over 40 GHz was attained, a record broadband performance for directly modulated VCSELs. VCSELs with slightly detuned polarization modes are injection locked with controlled polarization angles. For the first time, a dual-resonance frequency response is observed, and is explained with a two polarization-mode injection-locked rate equation model.