A NOVEL TECHNIQUE FOR DOUBLE SIDE-BAND SUPPRESSED CARRIER MODULATION OF OPTICAL-FIELDS

We present a simple and efficient technique to produce double sideband suppressed carrier (DSBSC) modulation for coherent analog optical communications. When operating a Mach-Zehnder electro-optic modulator at the appropriate bias point the carrier exists one of the output ports while the information carrying sidebands exit the other output port. The absence of a strong carrier component in the DSBSC output allows the use of an optical amplifier immediately following the modulator where the light signals are still relatively strong hence preserving the high S/N. In our experiments using heterodyne detection at 1319 nm, we show a -28-dB carrier suppression using a commercial M-Z modulator.