Suppressing the turn-off-induced pulsations in VCSELs using an elevated oxide-layer structure

We have demonstrated that, in elevated oxide-layer vertical-cavity surface-emitting lasers (VCSELs) where the spacing between 1-lambda cavity and oxide layer is 9lambda/4, a variety of turn-off-induced abnormalities such as secondary pulsations, bumps and tails is effectively suppressed. Compared are turn-off transient responses of conventional and elevated oxide-layer VCSELs with the oxide-aperture diameter of approximately 6.6 microm. The "on"- and "off"-current dependence of the turn-off-induced transient responses and bit rate dependence of the timing jitters show that the elevated oxide-layer structure effectively suppresses the turn-off-induced pulsations to less than half of the conventional one, which enables the VCSEL transmitter to operate without deleterious effects by the turnoff-induced pulsation.