Various materials are known for use in the telecommunications and optical industry for the fabrication of lasers, waveguides, modulators and various other components which otherwise manipulate light. Attempts have been made to arrive at solid-state athermal devices, but such attempts have only been varyingly successful. While a plethora of available glasses have some athermal characteristics, traditional glasses will not sufficiently satisfy the requirements of this invention.
Glasses termed “athermal” are commonly used in Fabry-Perot interferometers. These interferometers are often used in high-resolution spectrometers, and as the optical resonator component of a laser. See, e.g. Bass, M. Handbook of Optics: Fundamentals, Techniques, and Design, McGraw-Hill, Inc., New York (1995); Saleh, B. E. A., and Teich, M. C., Fundamentals of Photonics, John Wiley and Sons, Inc., New York (1991). The governing equation (from Bach, H. and Neuroth, N., The properties of Optical Glass, Springer, Germany (1995)) for an “athermal glass” intended for use in a Fabry-Perot Interferometer is:ΔOPL=L·ΔT(dn/dT+α·(n−1))  (1) wherein ΔOPL is the change in optical pathlength, L is the length of the glass component, ΔT is the change in temperature, dn/dT is the temperature coefficient of the refractive index, α is the coefficient of thermal expansion, and n is the refractive index of the glass.
Furthermore, the Fabry Perot interferometer should exhibit ΔOPL=0 with temperature fluctuation, and the resulting material property requirements for the “athermal glass” (from Bach, infra) are:dn/dT=α(n−1))  (2) Schott Glass Technologies, Duryea, Pa. has developed glasses specifically for this purpose (i.e., Ultran-30™, PSK-54™ and TiF-6™ in Table I; see, e.g. Schott Optical Glass Catalog). These glasses are termed “athermal” because when used in the classic Fabry Perot device, the device itself exhibits athermal behavior. However, the glass per se is not a solid-state athermal component because air gaps are machined or mechanically engineered into the glass to yield the device's overall athermal properties. However, telecommunications companies are currently developing devices that require purely solid-state athermal components (e.g., no air or vacuum is displaced as the material expands or contracts because the optical component is used completely in the solid-state; see FIG. 1.
Thus, there is currently a need for specialty materials and devices that exhibit solid-state athermal behavior, e.g., in the telecommunications industry.