Reverse bias leakage testing may be used to determine the health of a
vertical cavity surface emitting laser (VCSEL). When VCSELs are
integrated on a die with other electronic devices such testing may damage
the other electronic devices or be prohibited by circuits on the die
designed to protect the electronics from being reverse biased.
Accordingly, reverse bias testing may be facilitated by providing a
second ground pad, separate from the die ground pad, specific to the
VCSEL.