An optical waveguide, a package board having the optical waveguide, and manufacturing methods thereof are disclosed. The method of manufacturing an optical waveguide includes: forming a first reflective bump and a second reflective bump, which have inclined surfaces formed on sides opposite to each other and which are disposed with a predetermined distance in-between, on one side of a first cladding; forming a core between the first reflective bump and the second reflective bump; and stacking a second cladding over the one side of the first cladding such that the second cladding covers the first reflective bump, the second reflective bump, and the core. With this method, inclined surfaces can be formed by stacking a metal layer on the lower cladding and then selectively etching the metal layer, which can reduce lead time and enable a high degree of freedom in design.

An optical printed circuit board which can transfer optical signal and electric signals simultaneously, and a method of fabricating the optical printed circuit board. An optical printed circuit board which includes an upper cladding layer, a core layer positioned in the upper cladding layer that has a first reflecting surface and a second reflecting surface at both ends to guide optical signals, a lower cladding layer of which one side is in contact with the upper cladding layer and which has a circuit pattern and light connecting bumps on the other side corresponding to the first reflecting surface and the second reflecting surface, may provide the advantage of high optical connection efficiency.

An optical multiplexing and demultiplexing device of a type using a lens and a diffraction grating, which incorporates a waveguide array having waveguide channels with narrow spacings for facilitating high resolution, where the narrow spacings are realized by forming an etching groove between each adjacent waveguide channels and providing a measure for preventing optical coupling among the waveguide channels in the form of an air gap, or a layer having a refractive index lower than a cladding layer, or a layer for absorbing/reflecting light, which is provided in the etching groove. The device also incorporates a reflection mirror for reflecting the initially diffracted lights from the diffraction grating back to the diffraction grating, such that the diffracting grating diffracts the diffracted lights reflected back from the reflection mirror again to produce wavelength division multiplexed/demultiplexed optical signals in high resolution.

A method for releasing a micromechanical structure. A substrate is provided. At least one micromechanical structural layer is provided above the substrate, wherein the micromechanical structural layer is sustained by a sacrificial layer of a silicon material. An amine-based etchant is provided to etch the silicon material. That is, during performing a post-cleaning procedure with an amine-based etchant, polymer residue and the sacrificial layer of silicon can be simultaneously removed without any additional etching processes.

One embodiment of the present invention provides a system to facilitate using selective etching to form optical components on a circuit device. The system operates by receiving a substrate composed of a first material including a buffer layer composed of a second material. The system forms a sacrificial layer composed of a third material on the buffer layer. Next, the system forms an optical fiber core composed of a fourth material on the sacrificial layer. After the optical fiber core has been formed, the system performs an etching operation using a selective etchant to remove the sacrificial layer. The system also applies a cladding layer to the optical fiber core.