Title :
The role of photomask resolution on the performance of arrayed-waveguide grating devices
Author :
Lee, Chauhan D. ; Chen, Wei ; Wang, Qiang ; Chen, Yung-Jui ; Beard, Warren T. ; Stone, Dennis ; Smith, Robert F. ; Mincher, Rod ; Stewart, Ian R.
Author_Institution :
Dept. of Comput. Sci. & Electron. Eng., Maryland Univ., Baltimore, MD, USA
fDate :
11/1/2001 12:00:00 AM
Abstract :
The crosstalk performance of an arrayed-waveguide grating (AWG) multiplexer or demultiplexer is primarily caused by random optical phase errors introduced in the arrayed waveguides. Because the layout of waveguides on a wafer is patterned via photomask through the photolithography process, the resolution of a photomask has a direct influence on the phase errors of an AWG. The paper presents a theoretical analysis on the phase error caused by photomask resolution and other basic design parameters. Both calculation and measurement results show that a high-resolution photomask (better than 25 nm) is a critical requirement to produce low-crosstalk (less than -30 dB) AWG demultiplexers. We also investigate the effect of nonideal power distribution in the arrayed waveguides because it contributes considerable phase errors when material impurity is not well controlled during wafer fabrication. Basic criteria of power profile truncation, number of grating waveguides, and material index variation are also summarized
Keywords :
demultiplexing equipment; diffraction gratings; masks; multiplexing equipment; optical arrays; optical communication equipment; optical crosstalk; optical design techniques; optical fabrication; optical waveguide components; photolithography; wavelength division multiplexing; arrayed waveguides; arrayed-waveguide grating demultiplexer; arrayed-waveguide grating devices; arrayed-waveguide grating multiplexer; calculation results; critical requirement; crosstalk performance; design parameters; grating waveguides; high-resolution photomask; low-crosstalk; low-crosstalk AWG demultiplexers; material impurity; material index variation; measurement results; nonideal power distribution; performance; phase error; phase errors; photolithography process; photomask; photomask resolution; power profile truncation; random optical phase errors; resolution; theoretical analysis; wafer fabrication; Arrayed waveguide gratings; Error correction; Lithography; Multiplexing; Optical arrays; Optical crosstalk; Optical waveguide theory; Optical waveguides; Phased arrays; Power distribution;
Journal_Title :
Lightwave Technology, Journal of
