Abstract

We have demonstrated new switching and gas-sensing effects in integrated optics using input and output grating couplers and Bragg reflector gratings with 1200 lines/mm on planar SiO2–TiO2 waveguides. Switching is actuated by adsorption or desorption of water or other adsorbates on the waveguide surface through a change in the effective index of the guided modes under the grating. We derived theoretically the ultimate sensitivity limits of the grating devices employed either as switches or as gas sensors. Switching requires the adsorption and desorption, respectively, of less than one H2O monolayer. Sensors can detect variations in surface coverage of 1/100 of an H2O monolayer.

© 1984 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. W. Lukosz, K. Tiefenthaler, Opt. Lett. 8, 537–539 (1983).
    [CrossRef] [PubMed]
  2. See, for example, H. Kogelnik, in Integrated Optics, Volume 7, of Topics in Applied Physics, 2nd ed., T. Tamir, ed. (Springer-Verlag, Berlin, 1979), Chap. 2.3.
  3. V. Daneu, R. M. Osgood, D. J. Ehrlich, Opt. Lett. 6, 563–565 (1981).
    [CrossRef] [PubMed]

1983 (1)

1981 (1)

Opt. Lett. (2)

Other (1)

See, for example, H. Kogelnik, in Integrated Optics, Volume 7, of Topics in Applied Physics, 2nd ed., T. Tamir, ed. (Springer-Verlag, Berlin, 1979), Chap. 2.3.

Cited By

OSA participates in CrossRef's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (4)

Fig. 1
Fig. 1

(a) Schematic of switching or sensor experiment with an input grating coupler. S, substrate; F, waveguiding film; and C, air; with refractive indices nS, nF, and nC, respectively. αl, incoupling angle; Lx, length of grating; PMT, photomultiplier tube. (b), (c) Signal proportional to the intensity I(t) of guided TE0 mode (λ = 514 nm) versus time t for two sources of humidity at distance d from grating; (b) finger for a time of 2 sec, d ≃ 1–2 cm; (c) breathing experimenter d ≃ 20 cm.

Fig. 2
Fig. 2

Output grating coupler. The outcoupling angle αl changes with varying effective refractive index N of the guided mode under the grating.

Fig. 3
Fig. 3

Schematic of Bragg reflector. Its transmission and reflectance are changed by a Variation of the effective index N of the guided modes under the grating. (i) Incident, (t) transmitted, and (r) reflected modes.

Fig. 4
Fig. 4

Optical thickness nFdF of waveguiding film versus effective refractive index N of the TEm and TMm modes, nS = 1.47, nF = 1.8, nC = 1, and λ = 514.5 nm.

Equations (13)

Equations on this page are rendered with MathJax. Learn more.

± N = n sin α l + l ( λ / Λ ) ,
d N = n d ( sin α l ) = n cos α l d α l .
2 N sin θ l = l ( λ / Λ ) ,
δ N n δ ( sin α l ) λ / L x
2 δ ( N sin θ l ) λ / L x .
δ N / N 1 / l M ,
d ( d F ) d F = ( n F ) 2 1 ( n F ) 2 1 { N 2 [ 1 + ( n F ) 2 ] 1 N 2 [ 1 + ( n F ) 2 ] 1 } ρ ,
N = n F sin α F ,
4 π ( n F d F / λ ) cos α F + δ F , C ( α F ) + δ F , S ( α F ) = 2 π m ,
tan α F d α F = d ( d F ) / d eff ( α F ) ,
d eff ( α F ) d F + Δ z F , C ( α F ) + Δ z F , S ( α F )
d N / d ( d F ) = ( n F 2 N 2 ) / ( N d eff ) .
0 . 49 × 10 3 ( nm 1 ) at d F 120 nm for the TE 0 mode , 0 . 59 × 10 3 ( nm 1 ) at d F 175 nm for the TM 0 mode , 0 . 30 × 10 3 ( nm 1 ) at d F 400 nm for the TE 1 mode , 0 . 36 × 10 3 ( nm 1 ) at d F 450 nm for the TM 1 mode .

Metrics