Intraband entanglement–assisted cavity electro-optic quantum transducer

Quantum transduction is essential for connecting quantum technologies across varied frequencies. Achieving a positive quantum capacity of a traditional quantum transduction channel is a long-pursued goal in the field. However, to overcome the high threshold remains a major challenge, owing to practical limitations. Recently, an entanglement-assisted transducer was proposed based on a cavity-optic system [Opt. Quantum 2, 475 (2024)], where a modified bosonic loss channel was obtained, and the transduction efficiency could be enhanced by properly tuning the squeezing parameters. In this paper, we further identify three types of quantum channel enabled by this design, offering additional options for implementing the proposed transduction schemes. Compared with transducers without entanglement assistance, the scheme also shows a great enhancement in the conversion bandwidth for achieving high quantum capacity, further increasing its value in practical applications.