Microwave electro-optic mixer

摘要

An electro-optic mixer includes means for providing first and second microwave signals having first and second frequencies, respectively, a device for providing a source light, a first modulator responsive to the source light and to the first microwave signal for producing a first modulated optical signal, a second modulator cascade coupled to the first modulator and being responsive to the first modulated signal and to the second microwave signal for producing a second modulated optical signal having a frequency component at the sum or difference or both of the first and second frequencies, and means coupled between the first and second modulators for transmitting the first modulated signal to the second modulator. Each of the first and second modulators is a broadband, low drive voltage, traveling wave intensity modulator including a substrate having a first optical waveguide adapted to receive and transmit light therethrough with a first phase velocity; a buffer layer disposed on the substrate; and a coplanar waveguide electrode structure on the buffer layer for receiving an electrical signal propagating therethrough with a second phase velocity to phase modulate the light in the optical waveguide. The substrate has a sufficiently small thickness so that coplanar mode-substrate mode coupling substantially does not occur, and the coplanar waveguide electrode structure has a sufficiently large thickness so that the first and second phase velocities are equal.