Glass waveguides made using low melting point nitrate mixtures.

Silver-sodium ion exchange is a commonly used method for making waveguides in glass. This paper discusses two exchange media, KNO(3):AgNO(3) and AgNO(3) in NaNO(3):KNO(3) which increase the flexibility of the process and decrease its cost. Exchange in the KNO(3):AgNO(3) can be performed at temperatures as low as 150 degrees C, which is particularly useful for field assisted exchange. When exchange is performed in a NaNO(3):KNO(3) eutectic with small (

Optical waveguides in LiTaO(3): silver lithium ion exchange.

Silver lithium ion exchange has been found to produce optical waveguides in x-cut LiTaO(3)at temperatures well below the Curie temperature, producing waveguides that require no repoling. This process is attractive for integrated optics because LiTaO(3) is less susceptible to optical damage and has much lower birefringence than the more commonly used LiNbO(3) substrate. The exchange process has been studied as a function of temperature. Diffusion coefficients, activation energy, losses, and temperature dependence of the extraordinary index change are given. Index increases of Deltan(e) ~ 0.03-0.05 at lambda = 632.8 nm and losses of 0.8-1.3 dB/cm for the TE(O) mode are comparable with values for Ti-diffused guides in LiNbO(3), making this technique potentially useful for integrated optics applications.

Voltage tunable LiNbO(3) wavelength filters.

We describe here the design and operation of voltage tunable wavelength filters fabricated in titanium diffused LiNbO(3). The devices, based on the nonsymmetric interferometer, have channel separations of 11-31 nm at lambda= 1300 nm, and tuning rates of 3-10 nm/V. The periodic wavelength response of these filters allows them to be cascaded to combine or separate 2(N) channels in N stages.

Bistable optical switching using electrochemically generated bubbles.

We demonstrate a novel bistable optical waveguide switch, which may be suitable for incorporation in large-dimension optical cross connects. The switching is based on the electrolytic creation and catalytic destruction of bubbles and is both wavelength and polarization independent. Calculations indicate that low losses and cross talk, which are crucial for large switching arrays, can be achieved with the combination of materials used in the prototype. The intrinsic bistability of the switch eliminates the need for a holding voltage and permits matrix addressing.

Ion-exchanged optical waveguides for all-optical switching.

Current interest in all-optical waveguide devices has created a need for suitable nonlinear materials and fabrication techniques. To meet this need, we have made optical waveguides using ion exchange in two glasses, which were designed both to have large optical nonlinearities and to be compatible with the ion-exchange processing. We find that the choice of alkali metal ion in the glass has a major effect on the exchange process and on the optical quality of the ensuing guides. Guides made in one of these glasses have been used for demonstrations of spatial soliton propagation, which can be used as the basis of an all-optical switch.

Adiabatic invariance in GRIN channel waveguides and its use in 3-dB cross couplers.

We have extended the local normal mode approach of Burns and Milton to derive the condition for adiabatic invariance in graded-index channel waveguides. The results show that in spite of the index-grading and 2-D confinement, the inequality describing the adiabatic condition is basically the same as that for step-index slab waveguides. To verify the predictions of the theory, we have fabricated, using ion exchange in glass, a cross coupler with two asymmetric input channel waveguides and two symmetric output guides. The experimental results show equal output power (3.0 +/- 0.1 dB) from the two symmetric guides when either of the two unequal guides is excited, demonstrating excellent agreement with the theory.

Guided blue and green upconversion fluorescence in an erbium-ytterbium-containing silicate glass.

We observe guided blue and green upconversion fluorescence in an ion-exchanged waveguide that is fabricated in an erbium-ytterbium-codoped silicate laser glass. The guides are optically pumped at room temperature by using a Ti:sapphire laser with lambda = 880-980 nm; the observed fluorescence is in two bands, 480-490 and 520-560 nm, and results from multiphoton excitation.

Experimental observation of spatial soliton interactions.

We report the experimental observation of interaction forces between two fundamental spatial optical solitons in a nonlinear glass waveguide. Both attraction and repulsion were observed, depending on the relative phase between the solitons.

Observation of spatial optical solitons in a nonlinear glass waveguide.

We report the observation of spatial optical solitons due to the Kerr nonlinearity in a planar glass waveguide and present measurements of the nonlinear response obtained by placing a pinhole at the output of the waveguide. For input intensities greater than that required for the fundamental soliton, we observe breakup of the output owing to the effect of two-photon absorption.