Optical-Waveguide Band-Rejection Filters: Design

Abstract

A method for designing optical-waveguide band-rejection filters is presented that allows side-lobe levels to be reduced by several orders of magnitude while the rolloff rate of the response characteristics is not appreciably degraded. The method is based upon the control of the shape of the perturbation-amplitude envelope. We discuss in detail the particular case where the coupling coefficient of the waveguide filter takes the form of a modified raised cosine function along the length of the waveguide. Side-lobe level and rolloff can be traded off by appropriately choosing the index p of the function. Design curves are included that allow the optimization of filter responses for side-lobe levels or rolloff characteristics.

Mapping of Cleavage Sites for Restriction Endonucleases in λdv Plasmids

“…Among the large number of independently isolated 2dv plasmids [3,4] (and this work), Ldvh93 of 1.5 x lo6 daltons is the smallest autonomously replicating A DNA fragment presently known. On one extremity it contained the Hind I1 site at 78.4% and on the other the Bsu site at 82.9% which on the circular DNA become adjacent to each other.…”

“…Since the first isolation of a Adv plasmid (Advl) by Matsubara and Kaiser [2] additional 3,dv plasmids have been isolated [3,4] (and this work). All of them do contain the regulatory gene tuf and its promoter/ operator region pROR, but only some extend to the promoter,ioperator region p,OL.…”

Study of Linearly Chirped 1-Dimensional Bragg Gratings Using Confluent Hypergeometric Function

“…Most of these proposals are nevertheless either unsuitable for on-line implementation or short of meeting the cost-effective criterion for their applications. In a later study, Ouelette [2] explored further the advantage of early works on linearly chirped Bragg grating [3][4][5] which was known to allow large dispersion effects of either sign when operated in the reflection mode. The dispersion compensation module consists of a circulator and a fiber Bragg grating, as depicted in Fig.…”

Method of Designing a Corrugated Optical Waveguide Filter

“…Waveguide filters can be designed by periodicallyl-7) or aperiodically8~11) perturbing a suitable waveguide pararn' eter. Techniques to determine the required corrugation for given spectral-response characteristics have been re' ported by Matsuhara and Hill et al,12,13) Song and Shin, 14) Winick and Romanl5) and Wu et al 16) The approximate technique of Matsuhara modulates the corrugation period basing on an appropriate choice of the coupling coefficient profile. Song's method uses analysis of an inverse-scatter' ing problem to determine the required profile of the coupling coefficient.…”