Optical Waveguide Device With Antireflective Film
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Optical waveguide devices with thin substrates of 10 μm or less suffer from deterioration in operational characteristics due to stray light reflections and wavelength dependency, leading to increased propagation loss and phase differences, which affect yield rates and measurement times.
Innovation Solution
An optical waveguide device with a thin substrate of 10 μm or less, featuring an antireflective film on its side surfaces, including both the thin and supporting substrates, to minimize reflections and improve adhesion, thereby reducing operational characteristic deterioration and coupling loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a thin substrate of 10 μm or less is used to improve bandwidth and reduce drive voltage, then speed matching between microwave and optical wave is achieved and electric field efficiency is improved, but slab propagation light reflects from end faces and causes wavelength dependency and operational characteristic deterioration
Solution Approach 1:
The patent applies anti-reflective films to the end faces of the thin substrate to convert the harmful reflection of slab propagation light into beneficial suppression. By reducing the reflectivity at end faces through anti-reflective coating, the harmful wavelength dependency and operational characteristic deterioration are eliminated while maintaining the speed matching benefits of the thin substrate structure
2Use of energy by moving object
If a thin substrate of 10 μm or less is used to improve electric field efficiency, then drive voltage is reduced, but propagation loss increases due to slab propagation light reflection
Solution Approach 1:
The anti-reflective films convert the harmful energy loss from slab propagation light reflection into beneficial suppression. By applying anti-reflective coatings to end faces, the reflected light energy that would otherwise be lost is reduced, thereby decreasing propagation loss while maintaining the high electric field efficiency achieved through the thin substrate design
3Measurement precision
If measurement is performed in all wavelength bands to ensure specifications, then yield rate is affected when characteristics are inferior in one wavelength, but comprehensive verification is necessary
Solution Approach 1:
The anti-reflective films are applied in advance to the end faces of the thin substrate before final assembly and testing. This preliminary action prevents wavelength dependency and operational characteristic deterioration across all wavelength bands, ensuring that measurements will pass and improving yield rate by eliminating a major source of measurement failures
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The antireflective film effectively suppresses slab propagation light reflections, enhancing the operational characteristics of the optical waveguide device by reducing wavelength dependency and propagation loss, and improving adhesion to prevent peeling or chipping, while also reducing coupling loss when joined with an optical fiber.
Implementation Method 1
an antireflective film is formed on a part of a side surface of the optical waveguide device
Implementation Method 2
the substrate is made to have a small thickness of approximately 10 μm, whereby an effective refractive index of a microwave as a modulation signal is lowered, speed matching between the microwave and an optical wave is contrived
Implementation Method 3
this thin substrate is used after being adhered to another supporting substrate to have mechanical strength
Data Source
AI summary
An optical waveguide device that uses a thin substrate having an electro-optical effect and a thickness of 10 μm or less, in which slab propagation light that is reflected from an end face of the device is removed and thus deterioration in an operational characteristic is suppressed. The optical waveguide device includes: a thin substrate which has an electro-optical effect and thickness of 10 μm or less, and in which an optical waveguide is formed; and a supporting substrate that is adhered to the thin substrate through an adhesion layer. An antireflective film is formed on a part of a side surface of the optical waveguide device.