Apparatus and methods for measuring mode spectra for ion-exchanged glasses having steep index region
AssigneeCorning Incorporated
InventorsRostislav Vatchev Roussev, Vitor Marino Schneider
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Abstract
Apparatus and methods for measuring mode spectra for ion-exchanged glass substrates having a steep index region are disclosed. An interfacing fluid is provided between the coupling prism and the glass substrate. The interfacing fluid thickness is selected so that the variation in modal birefringence with fluid thickness is reduced to an acceptable level. The coupling prism can include a prism coating on the coupling surface so that the substrate-prism interface includes the prism coating. The coupling prism can also include stand-off members that serve to define the thickness of the interfacing fluid.
Claims13
A coupling prism apparatus for a prism coupling system for measuring mode spectra of an ion-exchanged waveguide having a refractive index ns, comprising:
- a coupling prism having a coupling prism body with a refractive index np, an input surface, an output surface and a coupling surface;
- a light source configured to emit and direct measurement light to the input surface of the coupling prism, the measurement light having a vacuum wavelength λ;
- a prism coating on the coupling surface, the prism coating having a thickness d2 and refractive index nc wherein 0.2λ≤nc·d2≤0.8λ;
- a substrate having a substrate body with a substrate surface, wherein the substrate body comprises the ion-exchanged waveguide adjacent the substrate surface;
- an interfacing fluid of refractive index nf disposed between the prism coating and the substrate surface to define a prism-substrate interface through which the measurement light is directed via the input surface of the coupling prism when measuring the mode spectra;
- and
- wherein nc<nf<ns<np.
Dependencies are inferred from the claim text.