Transmission filters with multiple flattened passbands based on chirped moire gratings

In-fiber chirped moire gratings (CMG's) are attractive as wavelength selective elements, and in particular as multiple passband transmission filters, for optical communications. However, as with single phase-shifted gratings, the passbands exhibit nonideal filter characteristics such as a Loren...

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Bibliographic Details
Published inIEEE photonics technology letters Vol. 10; no. 9; pp. 1283 - 1285
Main Authors Chen, L.R., Cooper, D.J.F., Smith, P.W.E.
Format Journal Article
LanguageEnglish
Published IEEE 01.09.1998
Subjects
Band pass filters
Bragg gratings
Chirp
Fiber gratings
Optical fiber filters
Optical filters
Optical interferometry
Passband
Refractive index
Shape
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Summary:In-fiber chirped moire gratings (CMG's) are attractive as wavelength selective elements, and in particular as multiple passband transmission filters, for optical communications. However, as with single phase-shifted gratings, the passbands exhibit nonideal filter characteristics such as a Lorentzian shape with narrow transmission peaks, and rounded, possibly broad bottoms, and are not suitable for system design. We show that we can flatten the passbands by introducing regions of constant refractive index within the CMG. By choosing the number, lengths, and location of the regions with constant refractive index, passbands with steep slopes and ripples less than 0.5 dB can be achieved.
Bibliography:ObjectType-Article-2
SourceType-Scholarly Journals-1
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content type line 23
ISSN:1041-1135
1941-0174
DOI:10.1109/68.705617