A system for converting digital data into an analog intensity modulated optical signal, the system comprising: (a) an electrically controllable modulator having M actuating electrodes for actuating said modulator, the modulator providing an optical signal output modulated in response to voltages applied to the M actuating electrodes; and (b) an electrode actuator having an electronic input for receiving an input data word of N bits and including a digital-to-digital converter, said electrode actuator providing a mapping of the input data word to a binary actuating vector of M bits and supplying the M bits of the actuating vector as a digital output to said M actuating electrodes, wherein M ≥ N, wherein the modulator has a non-linear response and wherein the electrode actuator is responsive to the mapped input data word to supply the M bits of the actuating vector to the actuating electrodes, to thereby generate by the actuating electrodes an output intensity corresponding substantially to the input data word, such that the output from the modulator more closely approximates to a linear response than would be achieved based directly on the input data words; wherein said modulator has a maximum dynamic range, and wherein said electrode actuating device is configured to actuate said actuating electrodes so as to generate modulation of the optical signal that approximates to a linear response across a majority of said dynamic range. (a) an electrically controllable modulator having M actuating electrodes for actuating said modulator, the modulator providing an optical signal output modulated in response to voltages applied to the M actuating electrodes; and (b) an electrode actuator having an electronic input for receiving an input data word of N bits and including a digital-to-digital converter, said electrode actuator providing a mapping of the input data word to a binary actuating vector of M bits and supplying the M bits of the actuating vector as a digital output to said M actuating electrodes, wherein M ≥ N, wherein the modulator has a non-linear response and wherein the electrode actuator is responsive to the mapped input data word to supply the M bits of the actuating vector to the actuating electrodes, to thereby generate by the actuating electrodes an output intensity corresponding substantially to the input data word, such that the output from the modulator more closely approximates to a linear response than would be achieved based directly on the input data words; wherein said modulator has a maximum dynamic range, and wherein said electrode actuating device is configured to actuate said actuating electrodes so as to generate modulation of the optical signal that approximates to a linear response across a majority of said dynamic range. wherein the modulator has a non-linear response and wherein the electrode actuator is responsive to the mapped input data word to supply the M bits of the actuating vector to the actuating electrodes, to thereby generate by the actuating electrodes an output intensity corresponding substantially to the input data word, such that the output from the modulator more closely approximates to a linear response than would be achieved based directly on the input data words; wherein said modulator has a maximum dynamic range, and wherein said electrode actuating device is configured to actuate said actuating electrodes so as to generate modulation of the optical signal that approximates to a linear response across a majority of said dynamic range.