All-optical noise spectroscopy of a solid-state spin

Noise spectroscopy elucidates the fundamental noise sources in spin systems, which is essential for developing spin qubits with long coherence times for quantum information processing, communication, and sensing. But noise spectroscopy typically relies on microwave coherent spin control to extract the noise spectrum, which becomes infeasible when there are high-frequency noise components stronger than the available microwave power. Here, we demonstrate an alternative all-optical approach to performing noise spectroscopy. Our approach utilises coherent Raman rotations of the spin state with controlled timing and phase to implement Carr-Purcell-Meiboom-Gill (CPMG) pulse sequences. Analysing the spin dynamics under these sequences enables us to extract the noise spectrum of a dense ensemble of nuclear spins interacting with a single spin in a quantum dot, which has thus far only been modelled theoretically. By providing large spectral bandwidths of over 100 MHz, our Raman-based approach could serve as an important tool to study spin dynamics and decoherence mechanisms for a broad range of solid-state spin qubits.

Different soliton pulse order effects on the fiber communication systems performance evaluation

<p>The study outlined the soliton pulse order effects on the performance efficiency of the optical transceiver systems. The power after fiber is reported for various Soliton pulse order. Max optical signal power (SP) and min optical noise power (NP) are clarified versus time after optical fiber for various soliton pulse order. As well as the max electrical power amplitude against time period is demonstrated after electrical filter for various soliton pulse order. It is reported that the optical transceiver performance efficiency can be upgraded with the first soliton order pulse. The soliton technique is used for high speed communication transmission systems. Soliton technique is used to compensate the dispersion and balanced with nonlinear effects. The soliton order effects is then discussed to choose the suitable soliton order for high speed system performance efficiency. The soliton techniques can be used also for extended ultra high transmion distance with high data rates.</p>

Optical Analysis of Hole Patterned Ag Nanoparticle Structure

A structure with periodic sub-wavelength nanohole patterns interacts with incident light and causes extraordinary optical transmission (EOT), with metal nanoparticles leading to localized surface plasmon resonance (LSPR) phenomena. To explore the effects of metal nanoparticles (NPs), optical analysis is performed for metal NP layers with periodic hole patterns. Investigation of Ag NP arrangements and comparisons with metal film structures are presented. Ag NP structures with different hole configuration are explored. Also, the effects of increasing light incident angle are investigated for metal NP structures where EOT peak at 460 nm wavelength is observed. Moreover, electric field distributions at each transmittance peak wavelengths and optical noise are analyzed. As a result, optical characteristics of metal NP structures are obtained and differences in resonance at each wavelength are highlighted.

Fast Blind Deblurring of QR Code Images Based on Adaptive Scale Control

With the development of 5G technology, the short delay requirements of commercialization and large amounts of data change our lifestyle day-to-day. In this background, this paper proposes a fast blind deblurring algorithm for QR code images, which mainly achieves the effect of adaptive scale control by introducing an evaluation mechanism. Its main purpose is to solve the out-of-focus caused by lens shake, inaccurate focus, and optical noise by speeding up the latent image estimation in the process of multi-scale division iterative deblurring. The algorithm optimizes productivity under the guidance of collaborative computing, based on the characteristics of the QR codes, such as the features of gradient and strength. In the evaluation step, the Tenengrad method is used to evaluate the image quality, and the evaluation value is compared with the empirical value obtained from the experimental data. Combining with the error correction capability, the recognizable QR codes will be output. In addition, we introduced a scale control parameter to study the relationship between the recognition rate and restoration time. Theoretical analysis and experimental results show that the proposed algorithm has high recovery efficiency and well recovery effect, can be effectively applied in industrial applications.

Analysis and Experimental Investigation of the Light Dimming Effect on Automotive Visible Light Communications Performances

The use of Visible Light Communications (VLC) in vehicular applications has become a major research area due to its simplicity, high performance to cost ratio, and great deployment potential. In this context, this article provides one of the very few analyses and experimental evaluations concerning the integration of a light dimming function in vehicular VLC systems. For this purpose, a vehicle-to-vehicle VLC prototype has been implemented and used to evaluate the systems’ communication performances in light dimming conditions, while decreasing the duty cycle from 40% to 1%, and increasing the communication range from 1 to 40–50 m. The experimental results showed that in normal lighting conditions, the VLC technology can easily support low duty cycle light dimming for ranges up to 40 m, while maintaining a 10−6 BER. Nevertheless, in strong optical noise conditions, when the system reaches its SNR limit, the communication range can decrease by half, whereas the BER can increase by 2–4 orders of magnitude. This article provides consistent evidence concerning the high potential of the VLC technology to support inter-vehicle communication links, even in light dimming conditions.

Investigation of sub-carrier multiplexed fiber optic link supporting WLAN and WCDMA

In this thesis, an optical fiber based radio access architecture that simultaneously provides services of the wireless local area network (WLAN) and the third generation (3G) mobile communication system is investigated. The sub-carrier multiplexed (SCM) technique of the fiber optic system is considered. The SCM architecture does not require frequency conversion and plays an important role enabling the WLAN to complement the cellular mobile communication systems so that the user can have both services as needed. In the SCM architecture, the two mediums that signals propagate are the air interface and the radio over fiber (ROF) link. In the air interface, the signal experience path loss and multipath fading that have effect on the system performance. The ROF link introduces nonlinear distortions and optical noise. The uplink and downlink analysis are performed in this thesis considering all the impairments from the air interface and the ROF link. Thereafter, numerical results are generated for both the uplink and downlink to illustrate the performance of the SCM architecture. The analysis identifies the interdependent relationship of the WLAN and the WCDMA system. The numerical results graphically illustrate such interdependent relationship. In the downlink, a 5 km ROF link operating at optimal power can support a WCDMA system with 1 km radius of coverage that has 26 dB of signal to distortion and noise ratio (SDNR); and a WLAN system with 400 m radius of coverage that has 27 dB of SDNR. The throughput of IEEE 802.11 WLAN depends on the medium access control. Hence, the medium access control is investigated and the throughput expression is modified to adapt to the SCM architecture where signals travel extra distance in a fiber.

Investigation of sub-carrier multiplexed fiber optic link supporting WLAN and WCDMA

In this thesis, an optical fiber based radio access architecture that simultaneously provides services of the wireless local area network (WLAN) and the third generation (3G) mobile communication system is investigated. The sub-carrier multiplexed (SCM) technique of the fiber optic system is considered. The SCM architecture does not require frequency conversion and plays an important role enabling the WLAN to complement the cellular mobile communication systems so that the user can have both services as needed. In the SCM architecture, the two mediums that signals propagate are the air interface and the radio over fiber (ROF) link. In the air interface, the signal experience path loss and multipath fading that have effect on the system performance. The ROF link introduces nonlinear distortions and optical noise. The uplink and downlink analysis are performed in this thesis considering all the impairments from the air interface and the ROF link. Thereafter, numerical results are generated for both the uplink and downlink to illustrate the performance of the SCM architecture. The analysis identifies the interdependent relationship of the WLAN and the WCDMA system. The numerical results graphically illustrate such interdependent relationship. In the downlink, a 5 km ROF link operating at optimal power can support a WCDMA system with 1 km radius of coverage that has 26 dB of signal to distortion and noise ratio (SDNR); and a WLAN system with 400 m radius of coverage that has 27 dB of SDNR. The throughput of IEEE 802.11 WLAN depends on the medium access control. Hence, the medium access control is investigated and the throughput expression is modified to adapt to the SCM architecture where signals travel extra distance in a fiber.

Frequency microcomb distillation for optical superchannel transmission

Optical frequency combs potentially can provide a compact and efficient light source for multi-Terabit-per-second optical superchannels. However, as the bandwidth of these multi-wavelength light sources is increased, it can result in low per-line power. Optical amplifiers can be used to overcome power limitations, but the accompanying spontaneous optical noise can degrade performance in optical systems. To overcome this, we demonstrate wideband noise reduction for comb lines using a high-Q microring resonator whose resonances align with the comb lines. When applying the proposed distillation to a superchannel system at 18 Gbaud, with 64-QAM sub-channels in a > 10 Tb/s optical superchannel, we find that noise-corrupted comb lines can reduce the optical signal-to-noise ratio required for the comb by ~ 9 dB when used as optical carriers at the transmitter side, and by ~ 12 dB when used as a local oscillator at the receiver side. By filtering with a MRR, we eliminate this degradation in OSNR.

Common-mode noise filtering with space-divided differential 2x2 VLC for V2V applications

Vehicle-to-Vehicle (V2V) Communication is one of the most promising application opportunities of Visible Light Communication (VLC). This paper suggests a novel transmission technique for VLC-V2V applications, called 2x2 Differential Transmission (2x2 DT). This transmission method exhibits excellent common-mode optical noise rejection performance. This beneficiary property is presented first with simulation results and later with real-life urban traffic measurement as well. After the promising simulation results, a demonstrational automotive-grade VLC-V2V link is presented and investigated for evaluation purposes. The link does not contain electrical filters, optical filters nor optical lenses, hence link costs are kept low and versatility is preserved. With our proposed 2x2 differential solution, both the transmission quality and common-mode optical noise rejection performance is outstanding. Due to the increased sensitivity of the differential VLC transmission regarding crosstalk between channels, a method is suggested for crosstalk reduction for high-quality differential transmission.