This paper presents a review of both active and passive ring laser devices. The operating principles the are developed discussed, with special emphasis given to problems associated achievement greater sensitivity stability. First-principle treatments nature quantum noise in gyro various methods designed avoid low-rotation-rate lock-in presented. Descriptions state-of-the-art devices current proposed applications (including test metric theories gravity using cavity laser) given.

Light-emitting diodes (LEDs) have been deployed for various applications in our daily lives. Similarly, image sensors or cameras integrated into mobile phones become common. Hence, visible light communication (VLC) using LED and phone is attractive provides low-cost wireless communication. In this paper, we propose demonstrate a VLC system color-shift-keying (CSK) modulation code-division multiple-access (CDMA) technology simultaneously the first time; camera used as receiver (Rx). CSK to...

Optical wireless communication (OWC) is an emerging area where research and development are growing worldwide. The radio-frequency (RF) spectral resource in traditional band has been exhausted, frequency allocation will be a big issue, particularly for the future 6G networks. non-terrestrial-networks (NTN) introduce new applications, such as automatic logistics with drones, satellite communication, underwater etc, making OWC inevitable ultra-broadband secure transmissions. This tutorial...

This paper discusses the issues involving design and fabrication of vertical-cavity surface-emitting lasers (VCSELs). A review basic experimental structures is given, with emphasis on recent developments in distributed Bragg reflectors, gain media, as well current optical confinement techniques. The describes present VCSEL performance, particular, those selective oxidation visible wavelength operation.

Abstract. Digital images of the sky obtained using a total imager (TSI) are classified pixel by into clear sky, optically thin and thick clouds. A new classification algorithm was developed that compares red-blue ratio (RBR) to RBR library (CSL) generated from captured on days. The difference, rather than ratio, between CSL resulted in more accurate cloud classification. High correlation TSI image aerosol optical depth (AOD) measured an AERONET photometer observed motivated addition haze...

Complementary Metal-Oxide-Semiconductor (CMOS) image sensors are widely used in mobile-phone and cameras. Hence, it is attractive if these can be as the visible light communication (VLC) receivers (Rxs). However, using CMOS challenging. In this work, we propose demonstrate a VLC link camera with data rate higher than frame of sensor. We first discuss analyze features sensor Rx, including rolling shutter effect, overlapping exposure time each row pixels, frame-to-frame processing gap, also...

In this demonstration, we first demonstrate a real-time phosphor-LED visible light communication (VLC) system with 37 Mbit/s total throughput under 1.5 m free space transmission length. The transmitter and receiver modules are compact size. Utilizing our proposed pre-equalization technology, the ~1 MHz bandwidth of phosphor LED could be extended to ~12 without using blue filter. Thus, increase in would enhance traffic data rate for VLC transmission. maximum bit-rate achieved by is Mbit/s,...

Visible light communication (VLC) is attractive as a supplementary method for future fifth-generation (5G) wireless owing to the shortage of radio-frequency bandwidth in conventional communications. The VLC systems reported literature are mainly based on PIN receivers (Rxs). It highly desirable if these signals can be detected by using built-in complementary metal-oxide-semiconductor (CMOS) cameras Rxs provide flexible and low-cost However, CMOS camera challenging. In this paper, we propose...

The light-emitting diode (LED) is among promising candidates of light sources in visible communication (VLC); however, strong internal polarization fields common c-plane LEDs, especially green result low frequency and limited transmission performance. This study aims to overcome the 3-dB bandwidth long-wavelength InGaN/GaN LEDs. Thus, semipolar (20–21) micro-LEDs (μLEDs) were fabricated through several improved approaches on epitaxy chip processes. μLED exhibits a 525 nm peak wavelength good...

Visible Light Communication (VLC) technology is an emerging using visible light modulation that, in the modern world, will mainly facilitate high-speed internet connectivity. VLC provides tremendous advantages compared to conventional radio frequency, such as a higher transmission rate, high bandwidth, low-power consumption, no health hazards, less interference, etc., which make it more prominent recent days. Due their outstanding features, including low cost, power µ-light-emitting diodes...

We propose a new scheme for ultrasensitive laser gyroscopes that utilizes the physics of exceptional points. By exploiting properties such non-Hermitian degeneracies, we show rotation-induced frequency splitting becomes proportional to square root gyration speed (Ω), thus enhancing sensitivity low angular rotations by orders magnitudes. In addition, at its maximum limit, measurable spectral is independent radius rings involved. This Letter paves way toward class miniature ring on chip.

Red, green, blue (RGB) light-emitting-diodes (LEDs) are used to increase the visible light communication (VLC) transmission capacity via wavelength-division-multiplexing (WDM), and color image sensor in mobile phone is separate different signals a filter array. However, due wide optical bandwidths of filters, there high spectral overlap among channels, inter-channel interference (ICI) happens. Here, we propose demonstrate an RGB VLC using CMOS with multi-input multi-output (MIMO) technique...

Visible light communication (VLC) is an advanced, highly developed optical wireless (OWC) technology that can simultaneously provide lighting and high-speed data transmission. A VLC system has several key advantages: ultra-high rate, secure channels, a lack of interference from electromagnetic (EM) waves, which enable wide range applications. Light-emitting diodes (LEDs) have been considered the optimal choice for systems since they excellent illumination performance. However, quantum...

In this study, we present a high-efficiency InGaN red micro-LED fabricated by the incorporation of superlattice structure, atomic layer deposition passivation, and distributed Bragg reflector, exhibiting maximum external quantum efficiency 5.02% with low droop corresponding to an injection current density <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m1"> <mml:mrow> <mml:mn>112</mml:mn> <mml:mtext> </mml:mtext> <mml:msup> <mml:mi...

Ultraviolet light-emitting diodes (LEDs) have been grown by metalorganic vapor phase epitaxy using AlN nucleation layers and thick n-type Al0.48Ga0.52N current spreading layers. The active region is composed of three Al0.36Ga0.64N quantum wells with barriers for emission at 290 nm. Devices were designed as bottom emitters flip-chip bonded to thermally conductive submounts an interdigitated contact geometry. ratio well 330 nm sub-band gap high 125:1 these LEDs. Output power 1.34 mW 300 mA...

In addition to the illumination purpose, using a light-emitting diode (LED) for indoor optical wireless communication has attracted much attention recently. Proposed and demonstrated is use of simple on–off keying (OOK) predistortion scheme together with first-order resistance-capacitance equalisation circuit increase modulation speed white-light high-brightness LED (HB-LED). Optical filtering complicated formats are not required. Since only OOK used, signal detection very simple. Also...

In order to reduce the cost for delivering future broadband services, network operators are inclined simplify architectures by integrating metro and access networks into a single system. Hence, extended reach passive optical (ER-PONs) have been proposed. ER-PON usually has four new features: high data rate in both upstream downstream signals (>1 Gb/s); extension >100 km; split ratio (>100); using wavelength division multiplexing (WDM). this work, we propose demonstrate highly spectral...

Optical blue filter is usually regarded as a critical optical component for high speed phosphor-based white light emitting diode (LED) visible-light-communication (VLC). However, the plays different roles in VLC when using modulations of on-off keying (OOK) or discrete multi-tone (DMT). We show that DMT system, may be unnecessary, and even degrade transmission performance (by reducing signal-to-noise ratio (SNR)). Analyses verifications by experiments are performed. To best our knowledge,...

The phosphor light-emitting diode (LED) has been widely used not only for indoor illumination but the optical transmitter (Tx) as well in visible light communication (VLC). However, transmission data rate is significantly limited by modulation bandwidth of LED because low-speed response phosphor. In order to enhance VLC system, we demonstrate a 3 × imaging multiple-input multiple-output (MIMO) system. Besides, pre-equalizer circuit extend Tx. Orthogonal frequency division multiplexing (OFDM)...

In this paper, we propose using an energy-efficient and low-cost 682-nm vertical-cavity surface-emitting laser (VCSEL) with 1-GHz modulation bandwidth for high-speed wireless visible light communication (VLC). Moreover, by spectral-efficient orthogonal frequency division multiplexing (OFDM) bit-and-power-loading algorithm, successfully demonstrate VCSEL-based transmission at 11.1 Gbps (10.2 in a raw data rate) over free-space length of 1.2 m under small bias current 3.5 mA. Furthermore,...

One challenge faced by the in-home light-emitting diode (LED) optical wireless communication is noises. Here, we first experimentally characterize effect of background noise to performance LED channel. We demonstrate using Manchester coding for mitigate noise. No adaptive monitoring, feedback, or filtering required. The theoretical and numerical analysis decoding process provided. Our experimental result shows that can significantly eliminate generated AC-LED operated at <; 500 kHz fluorescent light.