Phononic band-gap guidance of acoustic modes in photonic crystal fibers

The elastic modes guided along the axis of an optical fiber are obtained for an arbitrary finite cross section using waveguide finite element analysis. The band structure of acoustic phonons is obtained from this fullvector computation. The analysis is applied to the case of a photonic crystal fiber possessing a honeycomb lattice. It is shown that this fiber exhibits band gaps for elastic modes propagating along the longitudinal fiber axis. For frequencies within a band gap, the external boundary of the fiber becomes a defect of the phononic crystal that supports the propagation of guided elastic modes. Such boundary modes are very sensitive to the boundary conditions. The further introduction of a defect within the two-dimensional phononic crystal leads to the formation of highly confined elastic waveguide modes that copropagate in the same core volume as the guided optical mode. We consider the application of these properties to the suppression of stimulated Brillouin scattering and to enhanced collinear acousto-optical interactions. In particular, we obtain the optimum elastic modal shape that maximizes the acousto-optical scattering coefficient for given optical modes.

[1]  P. Santos,et al.  Active photonic crystals based on surface acoustic waves , 2003 .

[2]  B. Djafari-Rouhani,et al.  Acoustic band structure of periodic elastic composites. , 1993, Physical review letters.

[3]  B. Aalami,et al.  Waves in Prismatic Guides of Arbitrary Cross Section , 1973 .

[4]  B. Djafari-Rouhani,et al.  Coupling characteristics of localized phonons in photonic crystal fibers , 2003 .

[5]  S Guenneau,et al.  Sonic band gaps in PCF preforms: enhancing the interaction of sound and light. , 2003, Optics express.

[6]  E. Yablonovitch,et al.  Inhibited spontaneous emission in solid-state physics and electronics. , 1987, Physical review letters.

[7]  Knight,et al.  Single-Mode Photonic Band Gap Guidance of Light in Air. , 1999, Science.

[8]  P. Russell.  Photonic Crystal Fibers , 2003, Science.

[9]  B. Djafari-Rouhani,et al.  Out-of-plane propagation of elastic waves in two-dimensional phononic band-gap materials. , 2003, Physical review. E, Statistical, nonlinear, and soft matter physics.

[10]  Sylvain Ballandras,et al.  A full 3D plane-wave-expansion model for 1-3 piezoelectric composite structures. , 2002, The Journal of the Acoustical Society of America.

[11]  V Laude,et al.  Amplitude and phase control of ultrashort pulses by use of an acousto-optic programmable dispersive filter: pulse compression and shaping. , 2000, Optics letters.

[12]  C. Townes,et al.  Stimulated Brillouin Scattering and Coherent Generation of Intense Hypersonic Waves , 1964 .

[13]  P. Russell,et al.  Endlessly single-mode photonic crystal fiber. , 1997, Optics letters.

[14]  John,et al.  Strong localization of photons in certain disordered dielectric superlattices. , 1987, Physical review letters.

[15]  Eleftherios N. Economou,et al.  Band structure of elastic waves in two dimensional systems , 1993 .

[16]  B. Djafari-Rouhani,et al.  Guided elastic waves along a rod defect of a two-dimensional phononic crystal. , 2004, Physical review. E, Statistical, nonlinear, and soft matter physics.