Analysis for fabrication errors of arrayed waveguide grating multiplexers

Based on the transmission theory, parameter optimization is performed, and effects of fabrication errors on transmission characteristics are analyzed for a 33×33 polymer arrayed waveguide grating (AWG) multiplexer around the central wavelength of 1550.918 nm with the wavelength spacing of 0.8 nm. Simulated results show that fabrication errors result in the shift of the transmission spectrum, and lead to the increase of the crosstalk compared with the device theoretically designed. Furthermore, accumulation and compensation of fabrication errors are investigated. In order to realize the normal demultiplexing of the fabricated AWG device, the allowed fabrication errors are discussed.     

Polymeric 32-channel arrayed waveguide grating multiplexer using fluorinated poly (ether ether ketone)

In wavelength division multiplexing (WDM) systems, an arrayed waveguide grating (AWG) multiplexer is a key component. A polymeric AWG multiplexer has recently attracted much attention due to its low cost processing and a potential of integration with other devices. Fluorinated poly (ether ether ketone)(FPEEK) is excellent material for fabrication of optical waveguides due to its low absorption loss at 1.55-μm wavelength and high thermal stability. A 32-channel AWG multiplexer has been designed based on the grating diffraction theory and fabricated using newly synthesized FPEEK. During the fabrication process of the Polymer/Si AWG device, spin coating, vaporizing, photolithographic patterning and reactive ion etching (RIE) are used. The AWG multiplexer measurement system is based on a tunable semiconductor laser, infrared camera and a Peltier-type heater. The device exhibits a wavelength channel spacing of 0.8nm and a center wavelength of 1548 nm in the room temperature.     

聚合物阵列波导光栅复用器关键技术的研究

介绍了阵列波导光栅(AWG)复用器的工作原理;运用光栅衍射理论和马卡提里近似法,对中心波长为1.55 μm,波长间隔为1.6 nm的聚合物AWG进行参量设计,通过数值模拟验证了设计的正确性.用甲基丙烯酸甲酯类聚合物对AWG的制备工艺进行了研究,用铝作掩模制作了聚合物光波导,测试结果表明在1.55 μm处波导实现单模传输.     

32-channel arrayed waveguide grating multiplexer using low loss fluorinated polymer operating around 1550 nm

A 32 × 32 arrayed waveguide grating (AWG) multiplexer operating around the 1550 nm wavelength has been designed and fabricated using highly fluorinated polyethers. The propagation loss of the slab waveguide is about 0.3 dB/cm at 1550 nm wavelength. The channel spacing of the AWG multiplexer is 0.8 nm (100 GHz). The insertion loss of the multiplexer is 10.3-15.3 dB and the crosstalk is less than −20 dB.     

Arrayed waveguide grating multiplexer with high thermal stability on silicon

In this paper, certain important parameters are optimized for a polymer/Si arrayed waveguide grating (AWG) multiplexer by using grating theory. A 32-channel multiplexer is designed and fabricated using newly synthesized fluorinated poly (ether ether ketone) with a high thermal stability. The measured wavelength channel spacing is 0.796 nm, and center wavelength and 3-dB bandwidth are 1548 nm and 0.3 nm, respectively.     

A 32-channel 100 GHz wavelength division multiplexer by interleaving two silicon arrayed waveguide gratings

A 32-channel wavelength division multiplexer with 100 GHz spacing is designed and fabricated by interleaving two silicon arrayed waveguide gratings (AWGs). It has a parallel structure consisting of two silicon 16-channel AWGs with 200 GHz spacing and a Mach-Zehnder interferometer (MZI) with 200 GHz free spectral range. The 16 channels of one silicon AWG are interleaved with those of the other AWG in spectrum, but with an identical spacing of 200 GHz. For the composed wavelength division multiplexer, the experiment results reveal 32 wavelength channels in C-band, a wavelength spacing of 100 GHz, and a channel crosstalk lower than -15 dB.     

Design and fabrication of arrayed waveguide grating using fluoropolymer PFS-co-GMA

A 33×33 polymer arrayed waveguide grating (AWG) multiplexer is optimized and fabricated. This device is made of polymeric materials named 2,3,4,5,6-pentafluorostyrene-co-glycidylmethacrylate (PFS-co-GMA). The central wavelength and wavelength spacing are designed to be 1550.918 and 0.8 nm, respectively. The calculated results are: the 3-dB bandwidth is about 0.24 nm, insertion loss is about 8.4 dB and crosstalk is −33.7 dB. The corresponding measured results are: the center wavelength is about 1550.85 nm, wavelength channel spacing is about 0.81 nm, 3-dB bandwidth is about 0.35 nm, crosstalk is about −20 dB, insertion loss is between 10.4 dB for the central port and 11.9 dB for the edge ports.     

AWG-based WDM-PON monitoring system using an optical switch and a WDM filter

A new WDM-PON scheme with real-time monitoring based on a time-sharing method is proposed. It uses an optical time domain reflectometer (OTDR) to monitor multiple ports by integrating an optical switch (OSW) with a dense wavelength division multiplexer (DWDM) at the optical line terminal (OLT) site. Each downstream signal and its corresponding monitoring signal are separated by m times the free-space range (FSR) of an array waveguide grating (AWG). A bit error rate (BER) test in 2.5 Gb/s × 27 km is performed with and without turning on the OTDR. A small power penalty of 0.7 dB is observed compared to the back-to-back measurement.     

Analytical modeling of loss characteristics of a polymer arrayed waveguide grating multiplexer

Theoretical analysis is performed for the loss characteristics of a polymer arrayed waveguide grating (AWG) multiplexer around the central wavelength of 1.55 μm with the wavelength spacing of 1.6 nm. The total loss of the device includes the diffraction loss in the input and output (I/O) slab waveguides, bent loss caused by the AWG and I/O channels, leakage loss resulted from the high refractive index substrate, and propagation loss due to the absorption and scattering of the materials of the device. The effects of some structural parameters on the loss characteristics are investigated and discussed. The computed results show that when we select the core thickness as 4 μm, core width as 6 μm, pitch of adjacent waveguides as 15.5 μm, diffraction order as 50, the number of the arrayed waveguides as 91, that of the I/O channels as 17, confined layer thickness between the core and the substrate as 10 μm, distance between the focal point and the origin as 5500 μm, and central angle between the central waveguide and the x-axis (i.e. the vertical of the symmetrical line of the device) as 60°, the total loss of the device can be dropped to the range 3.79–7.93 dB.     

Fast Tunable Wavelength Sources Based on the Laser Diode Array

We report a demonstration of a fast wavelength tunable source (TWS) based on the laser diode array coupled to the arrayed waveguide grating (AWG) multiplexer. The switching and optical characteristics of TWS make it a candidate for implementing the wavelength-division space switch fabric for an optical packet/burst switching.     

Parameter optimization and structural design of polymer arrayed waveguide grating multiplexer

First some important parameters are optimized for the structural design of a polymer arrayed waveguide grating (AWG) multiplexer around the central wavelength of 1.55 μm with the wavelength spacing of 1.6 nm. These parameters include the thickness and width of the guide core, mode effective refractive indices and group refractive index, diffraction order, pitch of adjacent waveguides, length difference of adjacent arrayed waveguides, focal length of slab waveguides, free spectral range (FSR), the number of input/output (I/O) channels, and that of arrayed waveguides. Then the bent angles, radii and lengths of all the input/output channels and arrayed waveguides are determined. Finally, a schematic waveguide layout of this device is presented, which contains 2 slabs, 11 input channels, 11 output channels, and 91 arrayed waveguides.     

A novel wavelength dispersive device with a dispersive element based on staircase-like straight and parallel arrayed waveguides

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.     

阵列波导光栅线性系统理论分析及优化设计

运用线性系统理论分析了阵列波导光栅的模场特性 ,导出器件传输的数学模型即光栅方程。提出了设计阵列波导光栅阵列波导数M的新方法 ,该方法综合考虑了降低器件串扰以及收集发散光场的能力 ,与文献 [1 ]的方法相比简单且准确。分析了造成器件衍射损耗的原因 ,提出了降低器件衍射损耗的方法。给出了 8× 0 .8nm ,中心波长为 1 550nm的阵列波导光栅波分复用器的设计实例 ,并进行了数值模拟计算验证了文中所提方法的准确性。     

Improved Design of 8-Channel Silicon-on-Insulator (SOI) Arrayed Waveguide Grating (AWG) Multiplexer Using Tapered Entry into the Slab Waveguides

An improved design of silicon-on-insulator based 8 × 8 AWG multiplexer is presented using tapered entry into the slab waveguide. Our simulation result clearly shows significant enhancement of electric field from 0.44 V/m to 0.732 V/m, reduction in insertion loss from 7.13 db to 2.7 db, with bandwidth of 230 GHz and channel spacing 200 GHz while keeping other parameters within acceptable limits.     

Suppression of Polarization Dependence in the Design of a 11×11 Polymer/Si Arrayed Waveguide Grating

In this paper we report an effective work of polarization independence in the design of a 11×,11 polymer arrayed waveguide grating (AWG) multiplexer. Theoretical analysis of the polarization properties is given by using Marcatili method. Numerical simulations are performed for independent polarization and single-mode propagation of a rectangular waveguide and bent waveguide with various geometries. The polarization dependence of the AWG device is successfully suppressed by controlling the relative index difference (Δn) between the core and the cladding, ratio between the core width and thickness (a/b), and bent radius of arrayed waveguides, considering practical technical error. The transmission characteristics of two AWGs for two parameter groups of Δn = 1%,a/b = 2 and Δn = 0.8%, a/b = 1.5, show the wavelength shift of 3.5 and 0.02 nm, respectively. The later group of data, which is used in our work, strongly supports the optimum design that we have identified for the birefringence suppression.     

Improved Design of 8-Channel Silicon-on-Insulator (SOI) Arrayed Waveguide Grating (AWG) Multiplexer Using Tapered Entry into the Slab Waveguides

An improved design of silicon-on-insulator based 8 × 8 AWG multiplexer is presented using tapered entry into the slab waveguide. Our simulation result clearly shows significant enhancement of electric field from 0.44 V/m to 0.732 V/m, reduction in insertion loss from 7.13 db to 2.7 db, with bandwidth of 230 GHz and channel spacing 200 GHz while keeping other parameters within acceptable limits.     

Monolithically integrated 64‐channel silicon hybrid demultiplexer enabling simultaneous wavelength‐ and mode‐division‐multiplexing

A compact 64‐channel hybrid demultiplexer based on silicon‐on‐insulator nanowires is proposed and demonstrated experimentally to enable wavelength‐division‐multiplexing and mode‐division‐multiplexing simultaneously in order to realize an ultra‐large capacity on‐chip optical‐interconnect link. The present hybrid demultiplexer consists of a 4‐channel mode multiplexer constructed with cascaded asymmetrical directional‐couplers and two bi‐directional 17 × 17 arrayed‐waveguide gratings (AWGs) with 16 channels. Here each bi‐directional AWG is equivalent as two identical 1 × 16 AWGs. The measured excess loss and the crosstalk for the monolithically integrated 64‐channel hybrid demultiplexer are about ‐5 dB and ‐14 dB, respectively. Better performance can be achieved by minimizing the imperfections (particularly in AWGs) during the fabrication processes.

     

A high-speed optical receiver

The design and performance of a high-speed optical receiver for the 1.3m and 1.5m wavelength regions is described. The receiver comprises an InGaAs PIN photodiode feeding into a bipolar transimpedance preamplifier. Measured receiver characteristics are found to compare favourably with theoretical predictions.     

Optical wireless quantum communication coding system using decimal convertor

In this study, a system of microring resonators and an add/drop filter are used to generate a large bandwidth signal as a localized multi wavelength, applicable for continuous dense coding and continuous variable encoding generation. This technique uses the Kerr nonlinear type of light in the MRR to generate multi wavelength of bright and dark soliton for quantum network cryptography. Afterwards, generated bright and dark optical pulses are converted into digital logic quantum codes using a decimal convertor system in which transmission of secured information are performed via an optical wireless communication system. Results show that ranges of multi bright and dark soliton wavelengths from 1.45 to $1.65\,\upmu \mathrm{m}$ with central wavelength of $1.55\,\upmu \mathrm{m}$ could be simulated, where the FWHM and FSR of 50 and 1,440 pm are obtained, respectively.     

Modeling of arrayed waveguide grating for wavelength interrogation application

We have proposed and discussed a design of arrayed waveguide grating (AWG) for the application of wavelength interrogation. The spectral responses of a silica-based 16 channel AWG with channel spacing 1.6 nm have been simulated when different receiver waveguide spacing are used. It was found that the 3-dB bandwidth is reduced about 50% as the receiver waveguide spacing increasing from 20 μm to 30 μm. The effect of bandwidth of the spectral response on wavelength resolution of AWG based interrogator has been estimated and discussed.