ИСТИНА

We present a development of ideas about quantum optical gates for non-classical squeezed light, which are based on sum-frequency generation (SFG) process. We worked out a theoretical description of sum- frequency generation process with seeding by squeezed light in terms of Schmidt modes which allows to clarify known results and also opens new prospects for managing spectral and temporal properties of the input squeezed light. In the case when several modes of squeezed light are involved in SFG, new possibilities, such as switching the weights and probing the relative phases of these Schmidt modes are found