In the development of flat panel display techniques and digital image processing techniques, the data processing ability progresses so greatly, and it makes the three-dimensional display (3D display) possible. Recently, the 3D display technique develops so fast, it changes totally the traditional 3D viewing effect and makes 3D display become a possible technique in our daily life. In this paper, the different 3D techniques will be reviewed, and much more focus on the real spatial 3D display techniques, especially the challenges of the high-quality spatial 3D display to the optoelectronics will be analyzed, which will be the sources for the future ideal 3D display technique.
This paper presents the characteristics and advantages of polymer optical fiber (POF) sensors compared with common silica optical fiber (SOF) sensors. The development and application of POF sensors for strain measurement are introduced in detail. Because of the recent developments in POF technology, the future of POF sensors is considered optimistic.
This paper presents an overview on new progresses of millimeter wave (mm-wave) radio-over-fiber (RoF) system based on mm-wave generation by optical frequency multiplication (OFM), including generation of high-order optical side modes by optical modulation using dual-drive Mach-Zehnder modulator (DD-MZM) and enhancement of high-order optical side mode induced by selective amplification due to stimulated Brillouin scattering (SBS). The paper describes OFM by using DD-MZM in principle and verifies it in an experimental bidirectional 40 GHz RoF system. SBS amplification enhances the generated information-bearing mm-wave in downlink and also helps in producing a pure reference mm-wave for radio frequency-intermediate frequency (RF-IF) down-conversion in uplink. These efforts pushed the OFM technology of mm-RoF systems to achieve more and more feasibility and cost-effectiveness.
Elaborately-designed asymmetrical curved active waveguides are introduced to improve the gain properties of semiconductor optical amplifiers (SOAs) by internal distributed optical-feedback suppression. An analytical model of the double-energy-level system is utilized in the simulation and designed by the finite difference time domain (FDTD) method. Under a 280 mA driving current, the optimized curved SOA with the simple device structure without isolators performs a more than 18 dB fiber-to-fiber gain, 980 mW spontaneous emission power, and 13 dBm saturation power.
Forward error correction (FEC) may reduce the bit-error ratio (BER) and provide coding gain, so FEC is considered as a mandatory part in 10 Gbit/s Ethernet passive optical networks (10G-EPONs). First, the basic concepts of FEC and Reed-Solomon (RS) code are introduced in this paper. After a detailed description of the implementation of FEC in 10G-EPON, computed result shows that FEC based on
A 10-GHz clock recovery from a 16×10-Gbit/s optical time-division-multiplexed (OTDM) data stream is experimentally demonstrated using an electro-absorption modulator and 40-Gbit/s electric time-division-multiplexed (ETDM) demultiplexer. The recovered clock signal exhibits excellent stability, with root mean square (RMS) jitter of 328 and 345 fs corresponding to back-to-back and transmission over 100 km, respectively.
Technological improvements in free space optical communication systems have reduced the cost and alternatives to fiber optic transmission. The advantages of the free space optical link over fiber optic cabling are primarily economic. In line with the demand for gigabyte link from 10 Mbit/s to 10 Gbit/s in the market, the uses of free space optical communication systems have increased exponentially from 1995 to 2008. However, free space optics is subject to atmospheric effects such as attenuation and scintillation which can reduce link availability and may introduce errors not seen in fiber transmission. In this paper we argue that optical wireless communication is an alternative to fiber optic transmission in short and medium range wireless communications and we discuss that the liability and availability of the free space optical link is mainly determined by the local atmospheric condition, this is to say that the transmission quality may be affected by weather conditions. For the evaluation we constructed an experimental communication network with a free space system. One way to characterize the strength of the turbulence fluctuation is by examining the Rytov variance for a plane wave. This Rytov variance physically represents the intensity fluctuation induced by atmospheric turbulence.
Based on the definition of the fractional Fourier transform (FRFT) and irradiance moments in the cylindrical coordinate system, the propagation expressions and kurtosis parameter of beams generated by Gaussian mirror resonator passing through the ideal fractional Fourier transformation systems are obtained. The propagation properties and kurtosis parametric characteristic of the beams in the FRFT plane are analyzed in detail. Some numerical examples are given to illustrate the analytical results. The influences of the fractional order on the intensity distribution and the kurtosis parameter of the beams are also investigated. The results show that the intensity distribution and the kurtosis parameter of the beams in the FRFT plane are closely related to the fractional order and beam parameters.
An all-optical filter structure to simultaneously implement microwave bandpass and notch filter is proposed and experimentally demonstrated. The structure is based on a recirculating delay line (RDL) loop consisting of a semiconductor optical amplifier (SOA) followed by a tunable narrowband optical filter and a 10∶90 coupler. The converted signal is generated in a wavelength conversion process based on cross-gain modulation of amplified spontaneous emission in the SOA. The converted signal circulating in RDL loop realizes a negative bandpass response. The negative bandpass filter and a broadband allpass filter are synthesized to achieve a notch filter with flat passband which can excise interference with minimal impact on the wanted signal.
The laser diode (LD) partially end-pumped slab laser with hybrid resonator is a kind of novel solid-state laser that can achieve high power with high beam quality. Using this configuration, taking Nd:YVO4 as the slab gain media, a 123 W output was obtained when the pumping power was 265 W, and the optical-to-optical efficiency and slope efficiency were 46.4% and 52.4%, respectively. The beam quality
This paper presents the experimental results of the monolithic Tm:YAG nonplanar ring oscillator (NPRO) pumped by two kinds of laser diodes with different pumping spot sizes. By longitudinal pumping in continuous-wave operation, a single-frequency output power of 404 mW was obtained at room temperature, with a slope efficiency of 48.2%. The influences of the pumping spot sizes on the beam properties were also discussed.
A general expression for the electric field of a cylindrically polarized vector beam propagating in free space is derived on the basis of the exact fully vectorial solution of Maxwell equations in transverse Fourier space, which indicates that a cylindrical polarization can be regarded as the combination of radial and azimuthal polarizations, and the electric field retains cylindrical symmetry under the propagation. The simulation results denote that the longitudinal electric field depends on the ratio of the waist width to wavelength and the angle between the electrical vector and the radial direction; in particular, when this angle is 24.5°, a flattop intensity distribution is obtained at the plane
Laser polarimetric imaging can offer additional information of targets compared with the traditional intensity imaging method. It can be used to detect camouflaged targets and distinguish targets with the same reflectivity, which cannot be realized using the traditional imaging method. Based on the dual-rotation retarder technique, we have established a setup to acquire different polarization state images. The polarization degree of the target can be calculated and encoded to get the polarization degree image. Preliminary results and error analysis have been given to validate the system. The results show that the system has rational arrangement and can realize the function of target detection and discrimination. Also, the polarization degree change and spectrum changes have little influence on the system.
Single walled-carbon nanotube (SWCNT) thin film is one of the candidates for the next-generation flexible and transparent conductive thin film, which is a crucial component in various applications such as electrodes of flat-panel displays, solar cells, light emitting diodes, and touch panels. An intensive research work is underway to develop thin and flexible SWCNT films. The most important requirement of an SWCNT thin film is that it should show a low sheet resistance coupled with a high transparency. In this work, thin films of SWCNTs are prepared by vacuum filtration. The electrical properties of the as-prepared, annealed and HNO3-treated SWCNT films have been investigated. It is found that the square resistance can be significantly changed upon anneal and HNO3-treatment. A room-temperature ethanol alcohol sensor based on the SWCNT film has also been demonstrated.
In a homojunction device, a single organic layer assumes the multiple roles of hole, electron transportation, and emitter. Its ease in processing is highly desirable from the manufacturing point of view. In this paper, we shall describe the synthesis of a range of bipolar small molecules and conductive vinyl polymers for application in homojunction and heterojunction organic light emitting diodes (OLEDs). The bipolar materials, in general, consist of three basic building blocks: an arylamine, a 1,3,4-oxadiazole, and a polycyclic aromatic moiety. The achievement of charge balance can be validated either by direct measurement of electron/hole mobility or indirectly via optimization of device properties. A series of conductive vinyl copolymers containing hole transporting
In this study, we fabricated and characterized an InGaN/GaN multi-quantum-well (MQW)-based p-n junction photodetector (PD) for voltage-selective light-emitting and photo-detective applications. The photodetector exhibits a cutoff wavelength at around 460 nm which is close to its electroluminescence (EL) peak position. The rejection ratio was determined to be more than three orders of magnitude. Under zero bias, the responsivity of the device peaks at 371 nm, with a value of 0.068 A/W, corresponding to a 23% quantum efficiency. The overall responsivity gradually rises as a function of reverse bias, which is explained by the enhanced photocarrier collection efficiency.
Blue and green dual wavelength InGaN/GaN multi-quantum well (MQW) light-emitting diode (LED) has wide applications in full color display, monolithic white LED and solid state lighting, etc. Blue and green dual wavelength LEDs, which consist of InGaN strain-reduction layer, green InGaN/GaN MQW and blue InGaN/GaN MQW, were grown by metal-organic chemical vapor deposition (MOCVD), and the luminescence properties of dual wavelength LEDs with different well arrangements were studied by photoluminescence and electroluminescence. The experimental results indicated that well position played an important role on the luminescence evolvement from photoluminescence to electroluminescence.