Upon investigating the market on modulateable lasers and the market on controllers I found they somehow were not fitting. The lasers are almost exclusively anode on case, while the controllers, at least those from AnalogDevices, consider the external laser to be Anode on Vcc. LinearTechnology expects Cathode on GND.
Since we're working with metal cases, we cannot really shift the potentials. They don't really expect me to realize current mirrors at gigabit speeds ?
Rene