Wavelength Drift in CWDM Systems: Impact and Measurement

The research begins with an investigation of wavelength drift in Coarse Wavelength Division Multiplexing (CWDM) systems, especially in the context of temperature dependent wavelength drift. A simple model was proposed using a typical ‘application’ from ITU-T G.695. OptiSystem was chosen as the simulation platform due to its ease of use, the variety and flexibility of its inbuilt components and similar models simulated on the platform in the past. The research then investigates the measurement of wavelength drift focusing on how to determine an acceptable wavelength accuracy for a CWDM wavelength monitor. The chosen approach arose from observations of the results from a model of how wavelength drift impacts the most important system parameter in CWDM systems, which is error performance. The statistical confidence levels of Bit Error Ratio (BER) measurements taken by typical industry test and measurement equipment was considered and their statistical worst case BER results were calculated. An argument is made equating wavelength drift to an equivalent degradation of a links BER. Using the model developed a minimum wavelength accuracy of 0.1365 nm for the CWDM wavelength monitor was calculated. Following a survey of instruments marketed to the CWDM industry, a set of attributes that are representative of the different types of instruments available was made. These attributes were categorised into parameters and features. Each parameter and feature was considered in the context of a wavelength monitor for use in CWDM systems with a subsequent reclassification of the attributes into ‘essential features’ and ‘key parameters’, hence the attributes of a CWDM wavelength monitor were specified. An in-depth investigation of wavelength measurement operating principles was carried out with the aim of identifying a suitable technology to implement a CWDM wavelength monitor. The ratiometric wavelength measurement operating principle was chosen to implement a proof of principle CWDM wavelength monitor as it offers the best potential to meet the required specification with a least complex solution. The ratiometric wavelength measurement operating principle was discussed in more detail followed by an investigation of the maximum discrimination of the optical filter used in this technique. The limits on the maximum discrimination of the optical filter due to an optical sources wideband noise were then modelled with a proof of principle experiment carried out to validate the model

Electronic Photonic Integrated Circuits and Control Systems

Photonic systems can operate at frequencies several orders of magnitude higher than electronics, whereas electronics offers extremely high density and easily built memories. Integrated photonic-electronic systems promise to combine advantage of both, leading to advantages in accuracy, reconfigurability and energy efficiency. This work concerns of hybrid and monolithic electronic-photonic system design. First, a high resolution voltage supply to control the thermooptic photonic chip for time-bin entanglement is described, in which the electronics system controller can be scaled with more number of power channels and the ability to daisy-chain the devices. Second, a system identification technique embedded with feedback control for wavelength stabilization and control model in silicon nitride photonic integrated circuits is proposed. Using the system, the wavelength in thermooptic device can be stabilized in dynamic environment. Third, the generation of more deterministic photon sources with temporal multiplexing established using field programmable gate arrays (FPGAs) as controller photonic device is demonstrated for the first time. The result shows an enhancement to the single photon output probability without introducing additional multi-photon noise. Fourth, multiple-input and multiple-output (MIMO) control of a silicon nitride thermooptic photonic circuits incorporating Mach Zehnder interferometers (MZIs) is demonstrated for the first time using a dual proportional integral reference tracking technique. The system exhibits improved performance in term of control accuracy by reducing wavelength peak drift due to internal and external disturbances. Finally, a monolithically integrated complementary metal oxide semiconductor (CMOS) nanophotonic segmented transmitter is characterized. With segmented design, the monolithic Mach Zehnder modulator (MZM) shows a low link sensitivity and low insertion loss with driver flexibility

The Design of FTTH Network

The aim of this thesis is to explain the problems of optical access networks with wavelength division multiplexers, main purpose is to demonstrate the difference between theoretical and real measurement. The work is divided into several thematic areas. The introduction outlines the basic of telecommunications, fiber optics lasers, single mode, multimode, lasers fibers cables & cores, splitters division multiplexing system, there are known solutions discussed fundamental wavelength multiplexes and their possible combinations. The following chapter deals with the active elements such as AON, PON, which are essential part xWDM systems such as optical lasers, detectors and amplifiers. Another chapter focuses on passive elements, which form a key part of the wavelength multiplex. Methods of measurement of WDM/PON networks are discussed in the following part. The next section describes the topology used active and passive optical networks. The penultimate part of the work consists of architecture & technology of xWDM such as GPON and WDM-PON networks and comparing their transmission parameters. The final part of the paper presents the results of practical experimental measurements of optical access networks with wavelengths division multiplex while these results are compared with the theoretical output & methods of Optical lost test, OTDR & LSPM, with advantage & disadvantage of every methods. The second part of practical is the draft to the connection resident housing units of 30 houses, boarding-house (10 rooms) and 2 shops, 20 km distant from exchange. With comparing the possibilities of two options- passive and active optical network- PON system – WDM- Wave multiplex. Suggest the possibility of measuring and monitoring the created network.The aim of this thesis is to explain the problems of optical access networks with wavelength division multiplexers, main purpose is to demonstrate the difference between theoretical and real measurement. The work is divided into several thematic areas. The introduction outlines the basic of telecommunications, fiber optics lasers, single mode, multimode, lasers fibers cables & cores, splitters division multiplexing system, there are known solutions discussed fundamental wavelength multiplexes and their possible combinations. The following chapter deals with the active elements such as AON, PON, which are essential part xWDM systems such as optical lasers, detectors and amplifiers. Another chapter focuses on passive elements, which form a key part of the wavelength multiplex. Methods of measurement of WDM/PON networks are discussed in the following part. The next section describes the topology used active and passive optical networks. The penultimate part of the work consists of architecture & technology of xWDM such as GPON and WDM-PON networks and comparing their transmission parameters. The final part of the paper presents the results of practical experimental measurements of optical access networks with wavelengths division multiplex while these results are compared with the theoretical output & methods of Optical lost test, OTDR & LSPM, with advantage & disadvantage of every methods. The second part of practical is the draft to the connection resident housing units of 30 houses, boarding-house (10 rooms) and 2 shops, 20 km distant from exchange. With comparing the possibilities of two options- passive and active optical network- PON system – WDM- Wave multiplex. Suggest the possibility of measuring and monitoring the created network.

Design of a digital compression technique for shuttle television

The determination of the performance and hardware complexity of data compression algorithms applicable to color television signals, were studied to assess the feasibility of digital compression techniques for shuttle communications applications. For return link communications, it is shown that a nonadaptive two dimensional DPCM technique compresses the bandwidth of field-sequential color TV to about 13 MBPS and requires less than 60 watts of secondary power. For forward link communications, a facsimile coding technique is recommended which provides high resolution slow scan television on a 144 KBPS channel. The onboard decoder requires about 19 watts of secondary power

High-speed and Robust Integrated Silicon Nanophotonics for On-Chip Interconnects

Optical interconnects offer advantages over electrical interconnects such as higher bandwidth, low power, reduced interconnects delay, and immunity to electro-magnetic interference and signal crosstalk. However, in order for optical interconnects to be widely adopted, the technology must be made cost effective and must be simple to implement with CMOS electronics. Silicon photonics offers a great promise due to its inexpensive material and its compatibility with the current CMOS fabrication technology. Moreover, Silicon as a platform has the ability to integrate with different types of the optical components such as photodetector, modulator, light source, and waveguide to form a photonics integrated circuit. The goal of this work is to develop and fabricate devices that utilize a hybrid electronic-photonic integration to enable high performance optoelectronic computing and communication systems that overcome the barriers of electronics and dramatically enhance the performance of circuits and systems. We experimentally demonstrate a novel broadband optical time division multiplexer (OTDM) on a silicon chip. The system has a footprint× 700 micrometer and is inherently broadband with a bandwidth of over 100nm making it suitable for high-speed optical networks on chip. Also, we propose and fabricate a novel design to demultiplex the high bit rates of OTDM data using two differentially operated 5Gb/s modulators. Moreover, we propose a high-speed hybrid optical-time-division-multiplexing (OTDM) and wavelength-division-multiplexing (WDM) system that seamlessly generates high bit-rate data (\u3e200Gbit/s) from a low speed (5Gbit/s) quantum-dot mode locked laser pulse source. By utilizing time and wavelength domains, the proposed design is a promising solution for high-speed, compact and low-power consumption optical networks on chip. And finally, we experimentally demonstrate a robust, low insertion loss, compact Silicon ring resonator electro-optic modulator for Binary Phase Shift Key (BPSK) coding/decoding that encodes data in the phase of light. Our design improves significantly over recently demonstrated PSK modulator designs in terms of insertion loss and stability

A review of silicon subwavelength gratings: building break-through devices with anisotropic metamaterials

Abstract Silicon photonics is playing a key role in areas as diverse as high-speed optical communications, neural networks, supercomputing, quantum photonics, and sensing, which demand the development of highly efficient and compact light-processing devices. The lithographic segmentation of silicon waveguides at the subwavelength scale enables the synthesis of artificial materials that significantly expand the design space in silicon photonics. The optical properties of these metamaterials can be controlled by a judicious design of the subwavelength grating geometry, enhancing the performance of nanostructured devices without jeopardizing ease of fabrication and dense integration. Recently, the anisotropic nature of subwavelength gratings has begun to be exploited, yielding unprecedented capabilities and performance such as ultrabroadband behavior, engineered modal confinement, and sophisticated polarization management. Here we provide a comprehensive review of the field of subwavelength metamaterials and their applications in silicon photonics. We first provide an in-depth analysis of how the subwavelength geometry synthesizes the metamaterial and give insight into how properties like refractive index or anisotropy can be tailored. The latest applications are then reviewed in detail, with a clear focus on how subwavelength structures improve device performance. Finally, we illustrate the design of two ground-breaking devices in more detail and discuss the prospects of subwavelength gratings as a tool for the advancement of silicon photonics

Reconfigurable photonic logic architecture

The amorphous silicon photo-sensor studied in this thesis, is a double pin structure (p(a-SiC:H)-i’(a-SiC:H)-n(a-SiC:H)-p(a-SiC:H)-i(a-Si:H)-n(a-Si:H)) sandwiched between two transparent contacts deposited over transparent glass thus with the possibility of illumination on both sides, responding to wave-lengths from the ultra-violet, visible to the near infrared range. The frontal il-lumination surface, glass side, is used for light signal inputs. Both surfaces are used for optical bias, which changes the dynamic characteristics of the photo-sensor resulting in different outputs for the same input. Experimental studies were made with the photo-sensor to evaluate its applicability in multiplexing and demultiplexing several data communication channels. The digital light sig-nal was defined to implement simple logical operations like the NOT, AND, OR, and complex like the XOR, MAJ, full-adder and memory effect. A pro-grammable pattern emission system was built and also those for the validation and recovery of the obtained signals. This photo-sensor has applications in op-tical communications with several wavelengths, as a wavelength detector and to execute directly logical operations over digital light input signals