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Summary: IEEE JOURNAL OF QUANTUM ELECTRONICS, VOL. 34, NO. 4, APRIL 1998 729
Design of Widely Tunable Semiconductor
Lasers and the Concept of Binary
Superimposed Gratings (BSG's)
Ivan A. Avrutsky, Dave S. Ellis, Alex Tager, Hanan Anis, and Jimmy M. Xu, Senior Member, IEEE
Abstract--We propose a new concept of binary superimposed
gratings (BSG's) as multiwavelength grating reflectors and show
it as an effective structural improvement over the existing designs,
to both the fabrication process and device performance. We
also present a study of key design issues for widely tunable
lasers based on grating mirrors with a comb-like reflection
spectrum and summarize simple design rules for the grating
part of the laser, based on analytical and numerical analysis.
The binary supergrating consists of elements of equal size whose
refractive index is allowed to be one of two possible values,
which are sequenced according to a binary optics formalism to
effect a spatial superposition of multiple sets of single-frequency
gratings, and its implementation is well within the standard e-
beam lithography limits. The calculations of lasing frequency,
mode, and side-mode suppression ratio of the tunable laser are
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