Method for manufacturing an optical device

An optical device comprising:

• a glass plate;
• a first trench disposed in the glass plate;
• a second trench disposed in the glass plate and having a first sidewall and an opposite second sidewall, wherein the first trench intersects with the first sidewall of the second trench, and wherein the second trench extends deeper into the glass plate than the first trench;
• a waveguide disposed inside the first trench, wherein the waveguide is constructed of a material having a refractive index different from that of the glass plate;
• a mirror covering the second sidewall of the second trench;
• an encapsulation layer disposed over the glass plate, the waveguide, and the second trench, wherein the encapsulation layer covers all of an upper surface of the waveguide and all of an upper surface of the glass plate, wherein the second trench is filled with the encapsulation layer so that a portion of the encapsulation layer in the second trench separates the waveguide from the mirror, wherein the encapsulation layer filling the second trench and covering all of the upper surface of the waveguide and all of the upper surface of the glass plate has a refractive index that is lower than the waveguide and different from the glass plate;
• and
• an optical path between the waveguide and the mirror through the portion of the encapsulation layer filling the second trench, wherein
• the encapsulation layer covers all of the upper surface of the waveguide during operation of the optical device, and
• the optical path is part of the optical device during operation of the optical device.

An optical device comprising:

• a glass plate comprising a major surface;
• a first trench disposed in the major surface of the glass plate, the first trench comprising a first planar sidewall and an opposite second planar sidewall;
• a second trench disposed in the glass plate, wherein the second trench comprises a first curved sidewall and a second curved sidewall, the first curved sidewall comprising an opening connecting with the first trench;
• a waveguide disposed inside the first trench, wherein the waveguide is formed of a material having a refractive index different from that of the glass plate;
• a mirror disposed on the second curved sidewall of the second trench;
• an encapsulation layer overfilling the second trench and having a refractive index that is different from the waveguide and the glass plate, the encapsulation layer comprising a first portion covering an outer upper surface of the waveguide and second portions filling the second trench;
• and
• a first optical path between the waveguide and the mirror through one of the second portions of the encapsulation layer filling the second trench and a second optical path from the mirror through another one of the second portions towards an exposed outer surface of the optical device,
• wherein the first and the second optical paths are part of the optical device during operation of the optical device, and
• wherein both the first curved sidewall and the second curved sidewall comprise a nonzero curvature perpendicular to the major surface of the glass plate.