Technology Transfer
Basic Technology for Manufacturing Polyimide Optical Waveguides

We offer basic technology and Know-how for designing, manufacturing and evaluating low loss, heat-resistant optical waveguides, using fluorinated polyimides having properties of heat resistance and optical transparency.

This is a basic technology for designing, manufacturing, and evaluating the properties of buried linear or curved polyimide optical waveguides. It uses fluorinated polyimides with control of refractive index and high optical transparency in the near infrared wavelength region, along with multilayering and photolithography of the polyimide film.

1. Optical Waveguides Design Technology

• Waveguide conditions of single-mode operation, and dimension settings.
• Component materials, and their optical properties.

2. Multi-layered Fluorinated Polyimide Film Forming Technology

• Control of the thickness of multi-layered polyimide films for the manufacture of buried optical waveguides.
• Know-how concerning facilities, equipment, instruments, etc., specific film conditions, heat treatment conditions, film thickness control, flattering, and multi-layering needed for films.

3. Waveguide Manufacturing Technology

• Core technology of this transfer.
• Basic technology for manufacturing optical waveguides on substrate, through multi-layered film forming and core patterning.

4. Optical Waveguide End Forming Technology

• Technology for forming smooth optical waveguide ends when finishing waveguides as optical components
• Facilities, equipment, etc. for cutting out optical waveguides, methods of cutting to the prescribed dimensions, optimal conditions for end smoothing.

5. Film Waveguide Manufacturing Technology

• Technology for creating substrate-less (self-standing) film optical waveguides, and stabilizing their properties
• Processing methods and conditions for achieving substrate removal, methods and conditions for stabilizing waveguide properties

6. Optical Waveguide Evaluation Technology

• Technology for measuring and evaluating the structure and optical properties of waveguides
• Equipment for measuring the structure of optical waveguides (core shape, dimensions), propagation mode, optical loss, and birefringence; configuration, operating procedures and Know-how for this equipment ; and basic measurement methods.

Optical wiring components (applications in opt-electronic devices), optical couplers, thermo-optic switches

A characteristic of NTT-AT technology transfers is that they are carried out at the initial stages of a technology (this differs from the method of disclosing technologies to other companies once the market has matured, and the product's value has fallen). NTT-AT usually transfers technologies when the market has yet to mature. There is some risk involved, but this method also carries with it the possibility that the technology will enjoy much greater development.

Typical Properties of Polyimide Optical Waveguides [wavelength : 1.3μm]

	on substrate	self-standing film
Structure	buried	buried
Propagation mode	single-mode	single-mode
Optical loss	0.4 dB/cm	0.3 dB/cm
Polarization dependent	0.1 dB/cm	less than 0.1 dB/cm
Thermal stability	380°C	380°C