A wavelength tunable optical transmitter for quantum key distribution
Ben Griffiths, Yuen San Lo, J. F. Dynes, Robert I. Woodward, Andrew J. Shields · 2023
Wavelength tunability in quantum key distribution (QKD) is desirable as noise can be introduced to the quantum channel if there is significant traffic near the same wavelength as the quantum data. Today’s QKD systems are typically of fixed wavelength due to the single-mode lasers used to encode qubits. We present a new optical transmitter design consisting of a multi-modal Fabry Perot laser optically injection locked by a tunable laser, capable of encoding qubits at GHz speeds with a tunable wavelength of < 65 nm and perform proof-of-principle BB84 QKD over a range of wavelengths with secure bit rates of order Mb/s.