of the present invention can be seen in fig2 fig2 is a schematic diagram of the buffer 10 as shown in fig1 the inputs to the buffer vin and vin u2212 are first applied into emitter followers q 1 b and q 2 b this differential signal is then applied to the differential pair comprising q 3 b and q 4 b the output signal of the differential pair is developed across identical collector resistors r 1 b and r 2 b and then applied to the output stage shown in fig3 emitter followers q 5 b and q 6 b are used to couple the signal to the output stage 12 the dc voltage vmodset generated in the output stage of fig3 is used in the circuit of fig2 this voltage along with transistor q 7 b and resistor r 3 b provides for the adaptive drive feature of the present invention this adaptive drive feature allows for the output voltages provided by the buffer to be larger when the vcsel modulation current is larger the amplifier abuf and resistors r 4 b and r 5 b essentially close a feedback loop that provides an appropriate operating condition in this circuit this operating condition is that the common mode voltage of the buffer output signals voutb and voutb u2212 equals vmodset vdc 1 in this way the buffer circuit outputs the proper voltages that will be used in the next circuit i e the output stage of the driver this compensation allows the buffer of the present invention to be used in a variety of vcsel driver circuits if the gain of amplifier.