Broadband Optical Transmission Research Articles

Enhanced Broadband Optical Transmission Through Ultrathin Metallic Nanomesh

We demonstrate the fabrication of metallic nanomesh with hexagonal array of circular holes by nanosphere lithography and measure the optical transmission spectrum of the nanomesh. The optical property of metallic nanomesh is theoretically investigated by the finite-difference time-domain method. The numerical simulation results indicate that the transmission properties of metallic nanomesh can be tuned by changing the hole diameter, period and film thickness. The optimized aluminum nanomesh shows enhanced broadband optical transmission of about 80%. This research provides a significant guidance for the design and fabrication of transparent metallic electrodes in optoelectronic devices.

Nanoshells as a high-pressure gauge analyzed to 200 GPa

In this article, we present calculations that indicate that nanoshells can be used as a high-pressure gauge in diamond anvil cells (DACs). Nanoparticles have important advantages in comparison with the currently used ruby fluorescence gauge. Because of their small dimensions, they can be spread uniformly over a diamond surface without bridging between the two diamond anvils. Furthermore, their properties are measured by broad-band optical transmission spectroscopy leading to a very large signal-to-noise ratio even in the multi-megabar pressure regime where ruby measurements become challenging. Finally, their resonant frequencies can be tuned to lie in a convenient part of the visible spectrum accessible to CCD detectors. Theoretical calculations for a nanoshell with a SiO2 core and a golden shell, using both the hybridization model and Mie theory, are presented here. The calculations for the nanoshell in vacuum predict that nanoshells can indeed have a measurable pressure-dependent optical response desirable for gauges. However, when the nanoshells are placed in commonly used DAC pressure media, resonance peak positions as a function of pressure are no longer single valued and depend on the pressure media, rendering them impractical as a pressure gauge. To overcome these problems, an alternative nanoparticle is studied: coating the nanoshell with an extra dielectric layer (SiO2) provides an easy way to shield the pressure gauge from the influence of the medium, leaving the compression of the particle as a result of the pressure as the main effect on the spectrum. We have analyzed the response to pressure up to 200 GPa. We conclude that a coated nanoshell could provide a new gauge for high-pressure measurements that has advantages over current methods.

Enhanced broadband optical transmission in metallized woodpiles

We present an optimized isotropic metal deposition technique used for covering three-dimensional polymer structures with a 50 nm smooth silver layer. The technology allows fast and isotropic coating of complex 3D dielectric structures with thin silver layers. Transmission measurements of 3D metallized woodpiles reveal a new phenomenon of enhanced optical transmission in broadband range (up to 300 nm) in the near IR.

On the Mechanisms of Relaxation in Electro-Optic Polymers

Electro-optic polymers have emerged as an interesting class of nonlinear optical materials suitable for application in broad band optical signal transmission. They take advantage of excellent propagation properties of amorphous polymer matrix with large nonlinear optical response of embedded chromophores. Different, important from practical point of view, aspects of material elaboration and chromophore orientation as well as its temporal stability are reviewed and discussed. A special attention is paid to the recently discovered problems of relaxation of nonlinear optical susceptibility due to the chromophores diffusion and aggregation, particularly important in the guest host systems.

Polarization control of optical transmission of a periodic array of elliptical nanoholes in a metal film.

The spectral dependences of polarized optical transmission of a metal film with a periodic array of elliptical nanoholes have been studied. Such nanostructured metal films exhibit enhanced broadband optical transmission that one can control by selecting the polarization of incident and (or) transmitted light.

전기적 시분할 다중 방식을 이용한 20 Gb/s 광송,수신기의 제작 및 성능 평가

20 Gb/s 광 전송 시스템을 위한 광 송신기와 수신기를 전기적 시분할 다중 방식으로 제작하고 그 특성을 측정하였다. 특히 광 수신기의 핵심 회로인 클럭(19.906㎓) 추출 회로의 구현을 위해 반파장 지연 선로와 상용화된 EX-OR 소자를 이용한 NRZ-PRZ 변환기와 유전체 공진기를 이용한 협대역 대역통과 필터 및 마이크로스트립 대역통과 필터를 설계, 제작하였으며, 최종적으로 수신부에서 1:2로 역다중화된 10 Gb/s 신호의 비트 오율(BER)을 측정하였다. 제작된 송ㆍ수신기를 직접 연동하였을 때, 수신기의 수신 감도는 BER <TEX>$1{\times}10^{-12}$</TEX>에서 -26.2dBm을 나타내었다. We developed an optical transmitter and receiver for an electrical time division multiplexed (ETDM) 20 Gb/s optical transmission system, and experimentally investigated their characteristics. Especially, the clock extraction circuit, which is a key component in realizing broadband optical transmission receivers, was realized by using an NRZ-to-PRZ converter implemented with a half-period delay line and an EX-OR, a high-Q bandpass filter using a cylindrical dielectric resonator, and a microstrip coupled-line bandpass filter. Finally, the bit-error-rate of demultiplexed 10 Gb/s electrical signal after back to-back transmission was measured, and a high receiver sensitivity [-26.2 dBm for NRZ (<TEX>$2^{7}-1$</TEX>) pseudorandom binary sequence (PRBS)] was obtained

Simultaneous baseband and RF optical modulation scheme for feeding wireless and wireline heterogeneous access networks

In this paper, a novel modulation scheme that allows broad-band optical data transmission at both baseband and millimeter-wave RF carriers at twice the local-oscillator frequency is investigated. The dispersion-induced carrier suppression may be overcome by properly setting the optical transmitter parameters. Three different configurations for the modulation scheme are modeled and simulation and experimental results are provided. The key parameters of these configurations are optimized in order to achieve the best performance in broad-band heterogeneous millimeter-wave wireless and wireline access networks.

High electron mobility transistor lightwave receiver for broad-band optical transmission system applications

The design and construction of a broadband transimpedance lightwave receiver which features packaged, commercially available high-electron-mobility transistors is described. The receiver was constructed on a standard teflon printed circuit board with packaged tailed 30- mu m-diameter germanium avalanche photodiode as photodetector. A sensitivity of -25.5 dBm for 10/sup -9/ bit error rate was achieved at 1.31 mu m with a 5-Gb/s nonreturn-to-zero pseudorandom sequence provided by a commercial data generator and 1:4 analog demultiplexing at the receiver output.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Linearization of Broadband Optical Transmission Systems by Adaptive Predistortion

Telecommunication par fibres optiques avec modulation d'intensite analogique directe de la diode laser

Investigation of Optical Feedback Effects on Laserdiodes in Broad-Band Optical Transmission Systems

Article Investigation of Optical Feedback Effects on Laserdiodes in Broad-Band Optical Transmission Systems was published on November 1, 1981 in the journal Journal of Optical Communications (volume 2, issue 4).