Optical Add Drop Filter For Wavelength Division Multiplexed Systems

An optical add/drop filter for wavelength division multiplexed systems and construction methods are disclosed. The add/drop filter includes a first ferrule having a first pre-formed opening for receiving a first optical fiber; an interference filter oriented to pass a first set of wavelengths along the first optical fiber and reflect a second set of wavelengths; and, a second ferrule having a second pre-formed opening for receiving the second optical fiber, and the reflected second set of wavelengths. A method for constructing the optical add/drop filter consists of the steps of forming a first set of openings in a first ferrule; inserting a first set of optical fibers into the first set of openings; forming a first set of guide pin openings in the first ferrule; dividing the first ferrule into a first ferrule portion and a second ferrule portion; forming an interference filter on the first ferrule portion; inserting guide pins through the first set of guide pin openings in the first ferrule portion and second ferrule portion to passively align the first set of optical fibers; removing material such that light reflected from the interference filter from the first set of optical fibers is accessible; forming a second set of openings in a second ferrule; inserting a second set of optical fibers into the second set of openings; and positioning the second ferrule with respect to the first ferrule such that the second set of optical fibers receive the light reflected from the interference filter.

A Unique, Cutting-Edge Approach to Optical Filter Design With more and more information being transmitted over fiber-optic lines, optical filtering has become crucial to the advanced functionality of today's communications networks. Helping researchers and engineers keep pace with this rapidly evolving technology, this book presents digital processing techniques for optical filter design. This higher-level approach focuses on filter characteristics and enables readers to quickly calculate the filter response as well as tackle larger and more complex filters. The authors incorporate numerous theoretical and experimental results from the literature and discuss applications to a variety of systems-including the new wavelength division multiplexing (WDM) technology, which is fast becoming the preferred method for system upgrade and expansion. Special features of this book include: * The theory underlying various architectures that can approximate any filter function * Filter design techniques applicable to a broad range of materials systems-from silica to fiber to microelectromechanical (MEM) systems * Design examples relevant to filters for WDM systems and planar waveguide devices * 250 figures as well as problem sets for use in graduate-level studies

This is the first book dedicated to wavelength filters for fibre optics. It provides a comprehensive account of the principles and applications of such filters, including their technological realizations. It explains the relevant performance parameters, the particular advantages and shortcomings of the various concepts and components, and the preferred applications. There is also in-depth information on the characteristics of commercially available devices.

"Silicon-on-insulator (SOI) has become an attractive material system for integrated photonic components due to its potential for integration of optical devices with complementary metal-oxide-semiconductor (CMOS) technology, and its low cost. Moreover, the high-index contrast of the SOI system enables fabrication of very compact devices. Wavelength division multiplexing (WDM) is a key technique for high-capacity telecommunication and data communication networks. Optical filters are one of the key components for implementation of photonic integrated circuits (PICs), and wavelength division multiplexed (WDM) optical communication systems.Researchers have demonstrated numerous configurations such as ring resonators, Mach-Zehnder interferometers, and integrated Bragg gratings for implementation of SOI-based optical filters. The goal of this thesis is to develop novel filter configurations for application in WDM systems and photonic integrated circuits, specifically bandwidth tunable filters and optical filters with multiple channels. To achieve this goal, first we review different possible approaches to implement bandwidth tunable filters and multi-channel filters. Contra-directional grating assisted coupler(CDGAC) is chosen to implement the chosen configurations.Using CDGACs three different configurations are chosen to implement the bandwidth tunable filters. The main drawback of all of previously demonstrated SOI integrated bandwidth tunable filters is that they have a limited bandwidth tunability range. However in this thesis by cascading two CDGACs with different periods, a bandwidth tunable add-drop filter with bandwidth tuning range of 10.6 nm is implemented. This structure has a working range limited to 17 nm. In addition to that, a fully reconfigurable add-drop filter consisting of two identical CDGACs in a loop configuration is proposed. Moreover, by omitting one of the two connecting waveguides from this structure, a bandwidth-tunable bandpass filter is realized.Finally, we propose the design, fabrication and measurement results of an add-drop filter with two drop channels which is a CDGAC with two different grating periods. The performance of proposed configuration is investigated by means of Fourier analysis which gives a thorough insight into the performance of the device and can be used to understand the behavior of similar configurations.We believe that the present thesis is a step forward towards implementation of optimal bandwidth tunable SOI filters. Moreover, the proposed two-channel optical add-drop filter can have a significant impact on the required device density to perform advanced filtering functions." --

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