Subnanosecond wavelength-tunable heterodyne receiver and analysis of its fundamental switching speed

We experimentally demonstrate subnanosecond tunability of a heterodyne receiver employing a fast-switching local laser oscillator. A <0.7-ns switching time and the feasibility to achieve hitless switching are demonstrated. Theoretical analysis of the transition process indicates that switching time shorter than a single bit slot can be realized in a typical receiver configuration with a fast-switching local oscillator.