1. An optoelectronic module, comprising:a driver circuit configured to output and/or receive an electrical signal;
a laser configured to convert the electrical signal into an optical signal;
an interconnect structure connecting the driver circuit and the laser, the interconnect structure comprising an electrically conductive substrate and a pair of transmission leads connecting the driver circuit and the laser and having a signal lead and a ground lead having lower impedance than the signal lead; and
a ground plane layer underlying the ground lead, wherein the ground lead is electrically coupled to the ground plane layer;
wherein an impedance of the signal lead is defined by its width and a distance to the ground plane layer, and the ground lead has a width that is larger than a width of the signal lead.