Theoretical Design And Performance Analysis Of Arrayed-waveguide Grating Multiplexers

Wavelength Division Multiplexing(WDM) technology is emerging inresponse to the rapid increase of bandwidth and capacity requirements in fibercommunication systems and networks. In recent years, high performance andsophisticated photonic devices have been developed to meet WDM systemrequirments. The components based on arrayed-waveguide gratings (AWG)represent one of the key enabling technologies for WDM systems. AWG possesses some advantages, such as easy optical integrating, narrowwavelength spacing, much more signal channels, low crosstalk and excellentparticular features, such as easy fabrication, low propagation loss, smallbirefringence, and easy control of the refractive index. AWG can offer some basic functions including multiplexing/demultiplexing, optical add/drop multiplexing (OADM) and opticalinterconnection. So the AWG multiplexer has attracted much more attention.Recently, considerable attention and great efforts have been focused on thedevelopment of polymer AWGs. The AWG multiplexer is composed of an arrayed-waveguide grating,input/output waveguides, and focusing slab waveguides .The arrayed-waveguide grating consists of series of regularly arranged waveguides, it joinsthe two slabs, and the lengths of adjacent waveguides differ by a constantvalue. The lengh difference results in the wavelength-dependent wavefronttilting, so light convergence in the output slab is frequency-dependent; thearrayed waveguide grating operates like a diffraction orders, which leads towavelength resolutions of better than a nanometer despite its small overallsize of the order of centimeters. The main purpose of this thesis is elaborate the work principle of theAWG, detailed deduce some main parameters, summarize the concrete designmethods of the polymer AWG based on silicon substrate, then use thesetheories in an example. Also in this thesis we analysis the transmission and theloss properties of the AWG, and optimize a conventional AWG with theRowland-circle geometry by using the developed aberration theory. Its i吉林大学硕士毕业论文spectral response can be optimized and some performances are expected to beimproved. First this thesis introduces the development history, advantages and theapplication direction of the AWG. In the second part, the basic principle of theAWG is discussed, then the grating equation of the AWG as well as theangular dispersion, free spectral range (FSR) and frequency response arededuced in theory. The design theory of the AWG device is introduced in thethree section. A 33 33 channels, which operates around 1.55 μm, and whosewavelength channel spacing is 0.8 nm. This thesis gives the results of someparameters and the design drawing. Then the transmission properties of the AWG are analyzed, such as thetransmission spectra, pass frequency shift due to temperature, channelcrosstalk and polarization-dependence. Finally in order to improve the performance of the AWG, we try toreduce its aberration by the stigmatic points method based on the aberrationtheory. At the same time, we make the end-face of output waveguide to be astraight line instead of a circle line in the conventional Rowland-type AWG.So we get a new flat-field AWG. In this thesis we optimize a conventionalAWG with the Rowland-circle geometry by using the developed aberrationtheory. Its spectral response can be optimized and some performance areexpected to be improved. Then we choose the focal points of all wavelengthsof operation distributing on a straight line. The new type flat-field AWG isconvenient to connect with fiber-array directly. A low-aberration flat-fieldPolymer/Si 33 33-channel AWG is designed. We give comparison of someparameters and the design drawing.