Mach-Zehnder modulator with individually optimized couplers for optical splitting at the input and optical combining at the output

Optical modulator comprising:

• a substrate;
• an input light path on the substrate for receiving a light signal;
• an input optical coupler positioned on the substrate to receive the light signal from the input light path for splitting the received light signal;
• a first optical light path and a second optical light path positioned on the substrate for receiving the light signal from the input optical coupler;
• a first phase shift region and a second phase shift region positioned on the substrate and connected to the first optical light path and second optical light path, respectively, with each containing electrodes for applying a voltage to the first optical light path and the second optical light path;
• and
• a Y branch coupler positioned on the substrate for receiving the light signal from the first and second optical light paths for combining the light signal received from the and optical light paths and outputting a light signal.

A method of modulating an optical signal comprising the steps of:

• receiving an incident light signal;
• sending the light signal to an input optical coupler and actively tuning the coupler for splitting the light signal substantially equally;
• sending the split light signals into phase shift regions for changing the phase of the light signals;
• and
• receiving the light signals from the phase shift regions and combining them.