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|Title: ||Design and fabrication of integrated polymeric photonics devices for optical communication|
|Other Titles: ||Ke yong yu guang tong xun zhi su liao guang ji cheng qi jian de she ji ji zhi zuo|
|Authors: ||Chung, Kin Ki (鍾建奇)|
|Department: ||Dept. of Electronic Engineering|
|Degree: ||Master of Philosophy|
|Issue Date: ||2007|
|Publisher: ||City University of Hong Kong|
|Subjects: ||Optical communications -- Equipment and supplies|
Optoelectronic devices -- Design and construction
|Notes: ||CityU Call Number: TK5103.59.C59 2007|
Includes bibliographical references.
Thesis (M.Phil.)--City University of Hong Kong, 2007
xii, 116, 7, 9 leaves : ill. (some col.) ; 30 cm.
|Abstract: ||Nowadays, there is tremendous demand in ever-increasing internet bandwidth all over the world. One of the, possibly the best, solution to cater such a demand is through the realization of all optical network system. In such a system, the whole network should be transparent to signals by avoiding the unnecessary optical-to-electrical signal conversion and vice verse. As a result, the full bandwidth of the optical fiber may be fully utilized. Moreover we need a wide range of low-cost, compact, active and passive optical devices to realize such kind of optical network. In this project, we designed and proposed three optical devices, namely, 1) A single electrode operates 22 digital optical switch (DOS), 2) A linear response variable optical attenuator (VOA), and 3)An ultra compact 14 optical power splitter. The first two devices are active devices while the last one is a passive device, which are the basic building blocks of optical network system. The devices are designed based on the operation principle of a wide-angled X-junction and a wide-angled Y-junction structure. As a result, they can be very compact in size and highly integratable. In addition, they were fabricated using polymer materials, which offer a very attractive advantage of low cost at mass production. The key functions and main features of each devices are outlined below. 1) A single electrode operates 22 optical switches In compared with conventional X-junction design, the size of our switch is reduced by six times. This is because the whole design is realized by using only one asymmetric X-junction structure. Another uniqueness of our design is that the switching operation only requires one single electrode. As a result, the control circuitry required to drive this device is much simple than all other existing devices with similar functions. Our switch has a fairly fast rising time, ~100s, which is an order of magnitude faster than that of a conventional thermo-optic device. The average measured crosstalk is less than -20dB. The device finds many applications, such as optical path protection, circuit switching situation, etc. 2) A linear response Variable optical attenuator (VOA) One distinct feature of our VOA in compared with other similar devices is that it offers an excellent linearity over a wide dynamic range of 35dB (TE mode) with fast response (~0.2dB/Sec). Nearly all the existing design of VOAs offer a rather poor linearity and therefore require a much complicated control circuitry in driving the devices. Since our design is based on a similar X-junction structured proposed above, it shares the same advantage of very compact in size, and offering a much higher packing density. Our VOA finds many applications in optical communication system network for power regulation, channel equalization etc. 3) An ultra compact 14 Optical power splitter We have designed a very compact full-pitch 1x4 optical power splitter which is 20 times smaller in size compared with a conventional one. The simulated junction loss is 0.26dB with branching angle of 16. This is the lowest reported value achieved at such a large branching angle. The fabricated device is only 4mm in length with a measured excess loss of less than 1.3dB over entire C-band. Another other advantage of our design is that it only requires two different index materials and can be reproduced at a very low cost using embossing technique. In conclusion, three compact and low-cost polymer optical devices are proposed for the realization of optical network system. They form the fundamental building block of more complicated devices.|
|Online Catalog Link: ||http://lib.cityu.edu.hk/record=b2217926|
|Appears in Collections:||EE - Master of Philosophy |
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