Patent ID: 7023601

Claim:
A method of modulating the E-field of an optical carrier signal using a Mach-Zehnder modulator having a pair of independently controllable branches, the method comprising steps of: calculating respective phase and amplitude values φ(n) and S(n) of a desired optical E-field; scaling the calculated phase and amplitude values φ(n) and S(n) to obtain respective scaled phase and amplitude values φ′(n) and S′(n); using a phase response of the MZ modulator to calculate a phase signal component value V φ (n) required to produce the scaled phase value φ′(n); using an amplitude response of the MZ modulator to calculate the amplitude signal component value V S (n) required to produce the scaled amplitude value S′(n); calculating corresponding values of a pair of independent branch drive signals V L (t) and V R (t) in accordance with: V L ( t )= V φ ( t )+ V S ( t ) and V R ( t )= V φ ( t )− V S ( t ) and driving each branch of the Mach-Zehnder modulator with a respective one of the independent branch drive signals V L (t) and V R (t).