共查询到20条相似文献,搜索用时 253 毫秒
1.
We propose a novel 1.3/1.55 m wavelength demultiplexer for integration with lasers and detectors on the InP material system. A chirp grating is placed inside a multimode interference (MMI) structure to shorten the device length and increase wavelength tolerance. The simulation using the bi-directional beam propagation method proves that the demultiplexer can have very low insertion loss and high isolation ratio. The approach of grating fabrication is also described. 相似文献
2.
Semi-vectorial analysis of a compact wavelength demultiplexer based on the tapered multimode interference coupler
下载免费PDF全文
![点击此处可从《中国物理》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Based on a parabolically tapered multimode interference (MMI) coupler
with a deep-etched SiO2/SiON rib waveguide, a compact wavelength
demultiplexer operating at 1.30 and 1.55\mum wavelengths is
proposed and analysed by using three-dimensional semi-vectorial
finite-difference beam propagation method (3D-SV-FD-BPM). The results
show that a MMI section of 330.0\mum in length, which is only
76% length of a straight MMI coupler, is achieved with the
contrasts of 42.3 and 39.2dB in quasi-TE mode, and 38.4 and 37.8dB in
quasi-TM mode at wavelengths 1.30 and 1.55\mum, respectively, and
the insertion losses below 0.2dB at both wavelengths and in both
polarization states. The alternating direction implicit algorithm
with the Crank--Nicholson scheme is applied to the discretization of
the 3D-SV-FD-BPM formulation along the longitudinal direction.
Moreover, a modified FD scheme is constructed to approximate the
resulting equations along the transverse directions, in which the
discontinuities of the derivatives of magnetic field components
Hy and Hx along the vertical and horizontal interfaces,
respectively, are involved. 相似文献
3.
We constructed a lens-free in-line optical isolator by embedding an isolator chip in a thermally expanded core (TEC) fiber without complicated optical alignment. The chip consists of two pairs of rutile wedges and garnet plates. We fabricated the TEC fibers by heating a single-mode fiber with a 200-mum outer diameter; low loss and a spot diameter as large as 49 mum were successfully obtained. The fabricated isolator has excellent optical properties, an insertion loss of 0.45 dB, and an isolation of more than 50 dB at a 1.55-mum wavelength, which confirms the usefulness of the integration techniques. 相似文献
4.
We have investigated the spectral responsivity of porous silicon Schottky barrier photodetectors in the wavelength range 0.4-1.7 mum . The photodetectors show strong photoresponsivity in both the visible and the infrared bands, especially at 1.55 mum . The photocurrent can reach 1.8 mA at a reverse bias of 6 V under illumination by a 1.55-mum , 10-mW laser diode. The corresponding quantum efficiency is 14.4%. 相似文献
5.
The authors propose a high-performance 980 / 1550-nm wavelength multiplexer / demultiplexer based on the restricted-resonance self-imaging effect in a buried-type waveguide system. The device functions either as a multiplexer or a demultiplexer, depending upon the direction of light propagation. Using the modal propagation analysis (MPA), characteristics of the device are investigated. We carried out the design of the device and showed that the device performance can be optimized by appreciate selection of the coupler width. A demultiplexer with an insertion loss of 0.4 dB and contrast of 25.5 dB at wavelength 1550 nm and 32 dB at 980 nm is demonstrated. 相似文献
6.
1 Introduction Densewavelengthdivisionmultiplexing (DWDM )systemdeploysmulti wavelengthsinasinglefibertotransmitsignalssimultaneously .However,todroponespecifiedwavelengthsignalwithlowlossandwithoutcrosstalkswithotherwavelengthchannelsisnoteasy ,especial… 相似文献
7.
This investigation presents a novel design of dual-band demultiplexers based on a periodic hexagonal lattice of holes or rods
on silicon materials. The demultiplexing function can be applied by coupling between two defect waveguides at one wavelength
with no coupling then at another wavelength. Appropriately choosing the radius and number of separated rows yields a broad
bandwidth for one range of wavelengths. Two designs that use rods or holes to generate photonic crystals are realized. An
analysis based on finite-difference time-domain (FDTD) and plane wave expansion (PWE) methods demonstrates that a 1.3/1.55 μm
dual-band wavelength demultiplexer can have a very low insertion loss and high isolation ratio. 相似文献
8.
Design of a wavelength demultiplexer based on a parabolically tapered multimode interference coupler
A compact wavelength demultiplexer is designed for the operation at 1.30 and 1.55 μm wavelengths using the three-dimensional semi-vectorial beam propagation method. The parabolically tapered multimode interference (MMI) coupler based on the deep-etched SiO2/SiON rib waveguide is introduced into the present demultiplexer for reducing the length. The numerical results show that a MMI section of 330.0 μm in length, which is only 76% length of a straight MMI coupler, is achieved with the contrasts of 42.3 and 39.2 dB in quasi-TE mode, and 38.4 and 37.8 dB in quasi-TM mode at wavelengths 1.30 and 1.55 μm, respectively and the insertion losses below 0.2 dB. The modified finite difference scheme is applied to approximate the resulting equations along the transverse directions, in which the discontinuities of the derivatives of magnetic field components Hy and Hx along the vertical and horizontal interfaces, respectively, are involved. 相似文献
9.
10.
提出一种基于Si3N4/SiNx/Si3N4三明治结构多模干涉波导的偏振无关1×2解复用器,用于分离1310和1550 nm两个波长.通过合理选择三明治结构中间层SiNx的折射率,可以调节同一波长两个正交偏振态的拍长相等,实现偏振无关;根据多模干涉原理,通过合理选择多模干涉波导的长度与宽度,可以使两个波长的输出像点分别成正像和反像,实现解复用功能.运用三维有限时域差分法进行建模仿真,对结构参数进行优化,并对器件关键结构参数的制作容差进行了分析.结果表明:该器件多模干涉波导的尺寸为4.6μm×227.7μm,插入损耗低至0.18dB,输出波导间的串扰低至–25.7dB, 3dB带宽可达60 nm.另外,本文提出的器件采用Si3N4/SiO2平台,可有效减小波导尺寸,提高集成度,不仅实现了偏振无关,而且结构紧凑、损耗低,在未来的集成光路中具有潜在的应用价值. 相似文献
11.
Chudoba C Fujimoto JG Ippen EP Haus HA Morgner U Kärtner FX Scheuer V Angelow G Tschudi T 《Optics letters》2001,26(5):292-294
We report the generation of 14-fs pulses at 1.3mum with 80-mW average power at 100-MHz repetition rate by an all-solid-state Kerr-lens mode-locked Cr:forsterite laser. The laser spectrum covers wavelengths of 1230-1580 nm, with a FWHM of 250 nm. Since 1.3-mum wavelengths are close to the zero dispersion wavelength of Cr:forsterite, higher-order dispersion is the main factor limiting pulse durations. We use specially designed and fabricated double-chirped mirrors in combination with high-index PBH71 prisms to compensate for the intracavity dispersion over almost 300 nm. 相似文献
12.
We report what is believed to be the first demonstration of an optical parametric oscillator directly pumped by the 1.55-mum output of an erbium-doped fiber laser. The oscillator, based on periodically poled lithium niobate, produced 8-muJ idler output near 3.8 mum at a 500-Hz repetition rate when it was pumped with 100-muJ 60-ns pulses at 1.55 mum . Temperature tuning of the 50-mm-long PPLN crystal gave signal and idler ranges of 2.55 to 2.7 mum and 3.65 to 3.96 mum , respectively, limited by mirror reflectivity. A signal-tuning range of 40 nm was observed for 13.5 nm of pump tuning with a fixed grating period and temperature. The optical parameter oscillator could be operated at low temperature with no sign of photorefractive damage. 相似文献
13.
提出一种紧凑型偏振解复用器, 其中两条常规硅基波导作为输入/输出信号通道, 居于其中的槽式微环谐振腔用于偏振态/波长选择组件. 采用全矢量频域有限差分法详细分析了硅基常规及槽波导的模式特性, 结果发现其横磁模的模场布及其有效折射率相似, 而其横电模相应的特性则差异明显, 结果输入横磁模能够在谐振工作波长下从下路端口输出, 而输入横电模与微环耦合可以忽略, 直接从直通端口输出, 从而实现两偏振态的高效分离. 采用全矢量时域有限差分法详细分析了该偏振解复用器的光波传输特性, 结果表明, 当微环半径为3.489 μm时, 在1.55 μm工作波长下, 横磁模与横电模的消光比与插入损耗分别为 ~ 26.12 (36.67) dB与 ~ 0.49 (0.09) dB. 另外, 论文详细讨论了器件关键结构参数的制作容差, 并给出了输入模场在器件中的传输演变情况. 相似文献
14.
15.
We propose an optical circuit design method for coherent waves as a boundary value problem. The method produces a very compact circuit in which the refractive index pattern is automatically synthesized for given input and output fields with a numerical calculation. We employ the method to design a 1.3/1.55 microm wavelength demultiplexer and also describe the features of a circuit generated by use of the method. 相似文献
16.
Dumais P Villeneuve A Saher-Helmy A Aitchison JS Friedrich L Fuerst RA Stegeman GI 《Optics letters》2000,25(17):1282-1284
We report what is to our knowledge the first experimental evidence of nonlinear beam displacement in a strip-loaded GaAs/AlGaAs multiple-quantum-well waveguide with an asymmetric, nonlinear cladding. An intensity-dependent spatial displacement of ~2 mum was observed for the guided mode at a wavelength of 1.55 mum. Numerical simulations that correspond to the experiment are also presented. The device has the potential of providing a soliton-emission-based, ultrafast all-optical switch. 相似文献
17.
We generated pulsed quadrature-squeezed light by cross-phase modulation in single-crystal hexagonal CdSe at wavelengths of 1.4 to 1.55mum . We measured 0.4-dB squeezing (0.7 dB is inferred at the crystal) with 100-fs laser pulses. The wavelength and the intensity dependence, as well as variations in the local oscillator configuration, are examined. At higher intensities squeezing is shown to deteriorate owing to competing nonlinear processes. 相似文献
18.
A 1310 and 1550 nm coarse wavelength multi/demultiplexer based on benzocyclobutene (BCB 4024-40) polymer is demonstrated for the first time. The device is designed based on a combination of general interference and paired interference mechanisms of multimode interference (MMI). It is fabricated on BK7 glass substrate with a thin layer of SiO2 as cover. A cost effective chemical etching technique is used in the fabrication process to take advantage of the photosensitive nature of the polymer. The device length was significantly reduced by adopting the restricted multimode interference scheme, lower beat length ratio and cascaded MMI couplers. The measured crosstalk at 1310 nm was 14.4 dB and at 1550 nm was 20.6 dB. The measured insertion loss is around 3.2-3.5 dB for both ports. 相似文献
19.
20.
Oscar Martínez Matos María L. Calvo Siegfried Janz José A. Rodrigo André Delâge 《Optics Communications》2007,270(1):31-40
We propose a new type of arrayed waveguide grating (AWG) multiplexer/demultiplexer based on modified group refractive index. This device is composed by an array of straight and parallel waveguides of equal length and each waveguide consist of two sections with different width. The length of the two sections are changed from a waveguide to the adjacent one following a linear dependence resulting in a wavelength dispersive waveguide array. An example of the device design for silicon-on-insulator (SOI) platform is provided and numerical simulations have been carried out for various arrayed waveguide parameters. We demonstrate that the group index modification can be used for tailoring device dispersion properties, and that it can also result in new dispersion characteristics predicted numerically not observed in conventional AWGs. Additional advantages are that the demultiplexer does not necessarily require bending waveguide sections as in a conventional AWG (de)multiplexers, and thus yields highly compact devices with potentially very low insertion loss. Channel spacing of 1 nm have been predicted for sub-micron waveguides sizes. In this paper it is also proposed a novel wavefront converter based on waveguide array lens-like element with waveguides broadened sections. Numerical results for different input/output geometries are analized. 相似文献