Patent ID: 6256442
Filing Date: 2001-07-03
Classification: G02B

Abstract:
A method for making an integrated optical waveguide device for use in an environment having a temperature which changes, the method comprising the steps performed either sequentially or non-sequentially of:providing a planar substrate;providing a first waveguide arm and a second waveguide arm on the planar substrate, the first waveguide arm and the second waveguide arm each having a length defining a difference in lengths of .DELTA.L, the first waveguide arm and the second waveguide arm each including a core composition having a high index of refraction and a boron concentration B.sub.core, the first waveguide arm defining a first segment having a length L.sub.w and a waveguide dimension w.sub.1, a remainder of the first waveguide arm having a waveguide dimension w.sub.3, the second waveguide arm defining a second segment having a length L.sub.w and a waveguide dimension w.sub.2, the remainder of the second waveguide arm having a waveguide dimension w.sub.3, the first segment and the waveguide dimension w.sub.1 having a mode field effective index N.sub.1 dependent on the waveguide dimension w.sub.1, the second segment and a waveguide dimension w.sub.2 having a mode field effective index N.sub.2 dependent on the waveguide dimension w.sub.2, and the remainder of the first waveguide arms and the remainder of the second waveguide arm having a mode field effective index N.sub.3 wherein: ##EQU18##cladding the first waveguide arm and the second waveguide arm with a cladding composition having a low index of refraction, and a boron concentration B.sub.clad different from the boron concentration B.sub.core of the core composition so as to define a difference .DELTA.B between the boron concentration B.sub.core of the core composition and the boron composition B.sub.clad of the cladding composition; andathermalizing the integrated optical waveguide device by optimizing the difference in lengths .DELTA.L, the length L.sub.w, the waveguide dimension w.sub.1, the waveguide dimension w.sub.2, the waveguide dimension w.sub.3, and the difference .DELTA.B between the boron concentration B.sub.core of the core composition and the boron composition B.sub.clad of the cladding composition to provide a zero or near-zero thermal spectral shift when the integrated optical waveguide device is subjected to a change in the temperature.