A transducer capable of converting quantum information stored as microwaves into telecom-wavelength signals is a critical piece of future quantum technology as it promises to enable the networking of quantum processors. Cavity optomechanical devices that are simultaneously coupled to microwave fields and optical resonances are being pursued in this regard. Yet even in the classical regime, developing optical modulators based on cavity optomechanics could provide lower power or higher bandwidth alternatives to current technology. Here we demonstrate a magnetically-mediated wavelength conversion technique, based on mixing high frequency tones with an optomechanical torsional resonator. This process can act either as an optical phase or amplitude modulator depending on the experimental configuration, and the carrier modulation is always coherent with the input tone. Such coherence allows classical information transduction and transmission via the technique of phase-shift keying. We demonstrate that we can encode up to eight bins of information, corresponding to three bits, simultaneously and demonstrate the transmission of an 52,500 pixel image over 6 km of optical fiber with just 0.67% error. Furthermore, we show that magneto-optomechanical transduction can be described in a fully quantum manner, implying that this is a viable approach to signal transduction at the single quantum level.

Wavelength (om)WR5 Fig. 2. Measured optical SNRs and Q factors of optical carriers 100 nm) and is realized when nonlinear materials, such as optical fibers, are pumped bypicosecond optical pulses. It occurs due to the combined effects of self-phase modulation, cross-phase modulation, and parametric four-wave mixing. It isnoteworthythatthegeneratedSClight has high coherence and high SNR. Optical carriers are obtained by spectrally slicing individual longitudinal modes from the SC spectrum. Therefore, multiple carriers (multi-wavelength CW lights) can be generated by utilizing P wavelength demultiplexer whose channel spacing equals the repetition rate of the pump pulses. In Fig. 1, the ~omrce laser was a 1538 nm made-locked laser diode (ML-LD), generating a 4.3 ps, 12.5 GHz pulse train? It was then amplified with an EDFA and coupled into a palarilation-maintaining (PM) SC fiber? Thc output spectrum exhibited more than l00nm spectrum broadening.Thefigure shows that over 1000-channel, 12.5 GHzspaced optical carriers are generated. The spectrum around 1560 nm,which is more than 20 nm (2W ch) from the pump laser wavelength, ex^ hibits equally-spaced optical carriers.Noire characteristics (RIN and Q-factor) of each optical frequency were measured after one frequency was extracted with a 12.5-GHz-spaced AWG DEMUX? The channel crosstalk of the adjacentoprical frequencieswasgreaterthan-21 dB. The SNRs were calculated by integrating the RIN measured from 100 MHz to 2.5 GHz, and the Qfactors were measured aher externally madulating each channel in a LiNbO, modulator at 2.5 Gbit/s (2" -I PRBS). Figure 2 shows the wavelength dependencies ofthe SNRand the Q-factor. The SNR ranged from 21 dB to 35 dB for 100 nm range. The Q-factor exceeded 18.3 dB (BER S for the wavelength range of 1512-1580 nm, which is sufficient for multispan transmission.