Rare-earth ion doped crystals for hybrid quantum technologies are an area of growing interest in the solid-state physics community. We have earlier theoretically proposed a hybrid scheme of a mechanical resonator whic...Rare-earth ion doped crystals for hybrid quantum technologies are an area of growing interest in the solid-state physics community. We have earlier theoretically proposed a hybrid scheme of a mechanical resonator which is fabricated out of a rare-earth doped mono-crystalline structure. The rare-earth ion dopants have absorption energies which are sensitive to crystal strain, and it is thus possible to couple the ions to the bending motion of the crystal cantilever. This type of resonator can be useful for either investigating the laws of quantum physics with material objects or for applications such as sensitive force-sensors. Here, we present the design and fabrication method based on focused-ion-beam etching techniques which we have successfully employed in order to create such microscale resonators, as well as the design of the environment which will allow studying the quantum behavior of the resonators.展开更多
Free-space optical(FSO)communication technologies constitute a solution to cope with the bandwidth demand of future satellite-ground networks.They may overcome the RF bottleneck and attain data rates in the order of T...Free-space optical(FSO)communication technologies constitute a solution to cope with the bandwidth demand of future satellite-ground networks.They may overcome the RF bottleneck and attain data rates in the order of Tbit/s with only a handful of ground stations.Here,we demonstrate single-carrier Tbit/s line-rate transmission over a free-space channel of 53.42 km between the Jungfraujoch mountain top(3700 m)in the Swiss Alps and the Zimmerwald Observatory(895 m)near the city of Bern,achieving net-rates of up to 0.94 Tbit/s.With this scenario a satellite-ground feeder link is mimicked under turbulent conditions.Despite adverse conditions high throughput was achieved by employing a full adaptive optics system to correct the distorted wavefront of the channel and by using polarization-multiplexed high-order complex modulation formats.It was found that adaptive optics does not distort the reception of coherent modulation formats.Also,we introduce constellation modulation–a new four-dimensional BPSK(4D-BPSK)modulation format as a technique to transmit high data rates under lowest SNR.This way we show 53 km FSO transmission of 13.3 Gbit/s and 210 Gbit/s with as little as 4.3 and 7.8 photons per bit,respectively,at a bit-error ratio of 1∙10−3.The experiments show that advanced coherent modulation coding in combination with full adaptive optical filtering are proper means to make next-generation Tbit/s satellite communications practical.展开更多
基金YLC acknowledges support from the Ville de Paris Emergence Program and from the LABEX Cluster of Excellence FIRST-TF(ANR-10-LABX-48-01),within the Program“investissements d'Avenir”operated by the French National Research Agency(ANR)The project has also received funding from the European Union’Horizon 2020 research and innovation program under grant agreement No 712721(NanOQTech).
文摘Rare-earth ion doped crystals for hybrid quantum technologies are an area of growing interest in the solid-state physics community. We have earlier theoretically proposed a hybrid scheme of a mechanical resonator which is fabricated out of a rare-earth doped mono-crystalline structure. The rare-earth ion dopants have absorption energies which are sensitive to crystal strain, and it is thus possible to couple the ions to the bending motion of the crystal cantilever. This type of resonator can be useful for either investigating the laws of quantum physics with material objects or for applications such as sensitive force-sensors. Here, we present the design and fabrication method based on focused-ion-beam etching techniques which we have successfully employed in order to create such microscale resonators, as well as the design of the environment which will allow studying the quantum behavior of the resonators.
基金The project is financed by the H2020 EU Project VERTIGO(Grant Nr.822030)。
文摘Free-space optical(FSO)communication technologies constitute a solution to cope with the bandwidth demand of future satellite-ground networks.They may overcome the RF bottleneck and attain data rates in the order of Tbit/s with only a handful of ground stations.Here,we demonstrate single-carrier Tbit/s line-rate transmission over a free-space channel of 53.42 km between the Jungfraujoch mountain top(3700 m)in the Swiss Alps and the Zimmerwald Observatory(895 m)near the city of Bern,achieving net-rates of up to 0.94 Tbit/s.With this scenario a satellite-ground feeder link is mimicked under turbulent conditions.Despite adverse conditions high throughput was achieved by employing a full adaptive optics system to correct the distorted wavefront of the channel and by using polarization-multiplexed high-order complex modulation formats.It was found that adaptive optics does not distort the reception of coherent modulation formats.Also,we introduce constellation modulation–a new four-dimensional BPSK(4D-BPSK)modulation format as a technique to transmit high data rates under lowest SNR.This way we show 53 km FSO transmission of 13.3 Gbit/s and 210 Gbit/s with as little as 4.3 and 7.8 photons per bit,respectively,at a bit-error ratio of 1∙10−3.The experiments show that advanced coherent modulation coding in combination with full adaptive optical filtering are proper means to make next-generation Tbit/s satellite communications practical.
