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|Title: ||Novel application of diffractive optical elements in optical systems|
|Other Titles: ||Xin xing yan she guang xue yuan jian zai guang xue xi tong shang de ying yong|
|Authors: ||Wen, Fung Jacky (溫峰)|
|Department: ||Department of Electronic Engineering|
|Degree: ||Master of Philosophy|
|Issue Date: ||2007|
|Publisher: ||City University of Hong Kong|
|Subjects: ||Diffraction gratings.|
|Notes: ||xiv, 138 leaves : ill. 30 cm.|
Thesis (M.Phil.)--City University of Hong Kong, 2007.
Includes bibliographical references.
CityU Call Number: TA1750 .W46 2007
|Abstract: ||Dammann proposed the special type of diffraction grating which is periodic in nature
together with binary phase for achieving high splitting ratio. Later, researchers
proposed different kinds of methods for improving the performances. Dammann
Gratings can be used in many areas, and in this project, we aim to expand the
potential applications of employing Dammann Grating, specifically in the areas of
optical communications and optical measurements.
Firstly, Fiber-to-the-Home (FTTH) is a residential communication system in which
fiber goes though the user’s home. FTTH can provide much more bandwidth than
Asymmetric Digital Subscriber Line (ADSL) which is one of the existing common
broadband technologies. In addition, this network has the ability to provide all-round
services and to become more feasible. Dammann Grating is then one of the suitable
candidates in optical fiber communication. The proposed scheme using Diffractive
Optical Elements (DOE) will have great potential for fiber-to-home network when
compared with other techniques such as fused fiber couplers, waveguide splitter and
micro electro-mechanical systems (MEMS) which are all affected by high PDL and
uniformity loss. In this project, we will discuss the optical beam splitter performance in both 1D and 2D packaged silica and POF fiber arrays.
Secondly, the Circular Dammann Grating (CDG) is a diffraction grating which
produces circular beams in ring-shape at the image plane. Zhou, Zhao and Chung
proposed different techniques. However, there are pros and cons. In this thesis, we
present and analyze other novel approaches based on the concept of circular rotation,
Hankel transform and non-zero order binary annulus mask of the nth order diffraction
spots to achieve the same objectives as mentioned above with better results.
We have explored the feasibility study of employing CDG for measuring the angle of
an object. Both theoretical and experimental results show that it agrees well with the
calculation. Through the Charged Coupled Device (CCD) camera, the diameter of the
major axis in tilted CDG can be measured. The accuracy is governed by the focal
length of converging lens and the period of grating. Generally speaking, this design
could be applied in micro-systems with the benefit of easy and robust configuration.
To conclude, we demonstrated the feasibility studies of applying Dammann Grating
into PON splitter and optical measurement both theoretically and experimentally. We
believe that this grating could be widely contributed in many areas.|
|Online Catalog Link: ||http://lib.cityu.edu.hk/record=b2268789|
|Appears in Collections:||EE - Master of Philosophy |
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