Unconsidered but influencing interference in unmanned aerial vehicle cabling system

The increasing complexity of electrical and electronic systems in unmanned aerial vehicles (UAVs) has raised concerns regarding unwanted electromagnetic interference (EMI) due to limited compartment space. Recent studies have highlighted the UAV cabling as the primary pathway for interference. This paper presents a novel approach to investigating the effects of interference power, polarization angle, and distance from the interference source on EMI in UAV cable systems. Measurements and simulations were performed to analyze the influence of these factors on the radiation received by the cable. A linear dipole antenna, operating at a frequency of 905 MHz, served as the radiation source, while a single wire cable pair terminated with a 50-ohm resistor was employed as the victim. The findings reveal that the power transmitted by the source, the distance between the cable and the source, and the polarization angle have a significant impact on the electromagnetic interference received by the cable. Notably, a perpendicular orientation of the cable to the interference source (antenna) in the far-field yielded a reduction of up to 15 dBm in EMI. The results underscore the necessity for more sophisticated models and comprehensive measurements to fully comprehend the diverse factors affecting polarization losses in practical scenarios

The improvement of fiber-detection method to enhance the output of amplify-received relaying on FSO communications

The performance of free-space optical (FSO) communications that using an optical amplifier (OA) in the scheme of an amplify-received (AR)-relaying has a major drawback in the detection of input signal quality under the effects of turbulence. As an OA is based on a fiber-detection (FD) method to receive and delivers a signal at the amplification process stage, there is an opportunity to implement an optical filter to improve the quality of the input signal. In this paper, as the continuation of previous work on improvement of direct-detection, the optical filter is applied on the AR-relaying of optical signal detection, implementing an OA in the receiver. The novelty proposed in this work is the improvement of FD method where the OF is designed as the integration of cone reflector, pinhole and multi-mode fiber with an OA. The optical filter produces an optical signal, the input of the OA, which minimizes the effects of turbulence, background noise and the fluctuation of the signal spectral. Thus, OA in AR-relaying produces signal output with high power and rise up below threshold level. Additionally, an OF with a lower pinhole diameter produces the best quality of the signal spectral to be delivered into an EDFA. Through this implementation, the performance of optical relaying network on FSO can be significantly improved

Optimizing Coupling Region as Sensing Area in Optical Ring Resonator Sensor Applications

Optical Ring Resonators (ORR), whether based on fiber optics or an optical micro ring on substrate structures have been studied and explored extensively to be used for optical sensor applications. The outstanding advantage of optical ring resonator structure is its spectral response shape change due to the variations of the refractive index of the surrounding medium, medium loss due to absorption and scattering, and coupling loss between waveguides in the optical ring structure. The change of spectral response due to the variations of optical medium on the optical ring structure is a phenomenon that can be used to sense the optical property change of physical or biological materials. Some developments of Waveguide (WG) ORR sensors are in progress mostly for bio-sensor applications, since it is free from Electromagnetic Interference (EMI) and is non-physically destructive. In this paper, we discuss our research in developing optical bio-sensor in the form of a WG optical ring resonator. The focus of the research is optimizing the coupling region as sensing area to obtain the optimal coupling coefficient for the most sensitive sense. The results show that the variations of coupling coefficient is not linear with respect to the resonant peak output, such that we are able to locate the most sensitive coupling coefficient to sense

The improvement of fiber-detection method to enhance the output of amplify-received relaying on FSO communications

The performance of free-space optical (FSO) communications that using an optical amplifier (OA) in the scheme of an amplify-received (AR)-relaying has a major drawback in the detection of input signal quality under the effects of turbulence. As an OA is based on a fiber-detection (FD) method to receive and delivers a signal at the amplification process stage, there is an opportunity to implement an optical spatial filter (OSF) to improve the quality of an input signal. In this paper, as the continuation of previous work on the direct-detection, the OSF is applied on the AR-relaying. The novelty proposed in this work is the improvement of FD method where the OSF is designed as the integration of cone reflector, pinhole and multi-mode fiber with an OA. The OSF produces an optical signal, the input of the OA, which minimizes the effects of turbulence, background noise and signal fluctuation. Thus, OA in AR-relaying produces signal output with high power and rise up below threshold level. Additionally, an OSF with a lower pinhole diameter produces the best quality of the signal spectral to be delivered into an EDFA. Through this implementation, the performance of optical relaying on FSO can be significantly improved

Analysis of Hole Lifetime in SOI MOSFET Single-Photon Detector

Hole lifetime in the silicon-on-insulator (SOI) metal-oxide-semiconductor field-effect transistor (MOSFET) singlephoton detector was evaluated by the analysis of drain current histograms for different light intensities and substrate voltages. It was found that the peaks in the histogram corresponding to the larger number of stored holes grew as the gate bias decreased. This was attributed not to the increased light absorption efficiency or collection efficiency of the photo-generated holes, but to the prolonged hole lifetime presumably caused by the higher transverse electric field inside the body of SOI MOSFET.Keywords: hole lifetime SOI MOSFET, light absorption efficiency, single-photon detecto

EFEK PIN HOLE UNTUK MENEKAN EFEK MULTILENSA PADA KOMUNIKASI FREE SPACE OPTICS

Teknologi FSOC pada jaringan teresterial memanfaatkan media atmosfer yang sangat terpengaruh kondisi cuaca sebagai media propagasi informasi sinyal optik. Pengaruh kondisi cuaca ini menyebabkan media atmosfer mengalami turbulens. Akibat turbulens atmosfer, teknologi FSOC dihadapkan oleh tantangan terbesar dimana salah satunya terjadi efek multi lensa akibat gradient temperature di atmosfer yang menyebabkan sinar meleset dari titik penerima.Gangguan yang terjadi pada FSOC bersifat random dan fluktuatif dalam domain spasial dan waktu sehingga dilakukan pendekatan secara statistik untuk menganalisa gelombang yang dipropagasikan pada sistem FSOC. Pengujian eksperimen penelitian melalui pendekatan dengan teknik SISO FSOC (Single-input single output) dengan menggunakan laser He-Ne pada panjang gelombang 632 nm. Sistem dirancang dengan menggunakan pin hole di receiver FSOC dimana pada eksperimen ini terjadi peningkatan nilai SNR sebesar 7.3443 dB saat sistem diuji menggunakan pin hole 10 μm

Review of Orthogonal Frequency Division Multiplexing-Based Modulation Techniques for Light Fidelity

Light Fidelity (LiFi) technology has gained attention and is growing rapidly today. Utilizing light as a propagation medium allows LiFi to promise a wider bandwidth than existing Wireless Fidelity (WiFi) technology and enables the implementation of cellular technology to improve bandwidth utilization. In addition, LiFi is very attractive because it can utilize lighting facilities consisting of light-emitting diodes (LEDs). A LiFi system that uses intensity modulation and direct detection requires the signal of orthogonal frequency division multiplexing (OFDM) to have a real and non-negative value; therefore, certain adjustments must be made. The proposed methods for generating unipolar signals vary from adding a direct current, clipping the signal, superposing several unipolar signals, and hybrid methods as in DC-biased optical (DCO)-OFDM, asymmetrically clipped optical (ACO)-OFDM, layered ACO (LACO)-OFDM, and asymmetrically clipped DC-biased optical (ADO)-OFDM, respectively. In this paper, we review and compare various modulation techniques to support the implementation of LiFi systems using commercial LEDs. The main objective is to obtain a modulation technique with good energy efficiency, efficient spectrum utilization, and low computational complexity so that it is easy for us to apply it in experiments on a laboratory scale