Patent ID: 6600604
Filing Date: 2003-07-29
Classification: G02B,H04J

Abstract:
A thin film optical filter, comprising:first and second substrates; and a reflective layer provided between said first and second substrates, said reflective layer including a first mirror layer having a first plurality of thin film dielectric layers; a second mirror layer having a second plurality of thin film dielectric layers; and a thin film dielectric spacer layer provided between said first and second mirror layers, said reflective layer having an associated center wavelength, wherein said first and second substrates have a respective thickness and coefficient of thermal expansion chosen such that the center wavelength of said reflective layer is substantially independent of temperature, wherein said first and second substrates comprise quartz crystal, wherein each of said first and second substrates has an associated primary surface and an associated c axis crystallographic orientation which is substantially perpendicular to said associated primary surface, and wherein said first and second mirror layers are respectively provided on the primary surfaces of the first and second substrates and substantially perpendicular to the c axis.