Optical Module With Tapered Waveguide Core
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Solution Overview
Problem
Conventional optical modules experience reduced optical coupling efficiency due to the long distance between the optical fiber core and the mirror, leading to light flux expansion and increased propagation loss.
Innovation Solution
An optical module design featuring a substrate with a first groove containing an internal waveguide and a mirror portion, where the optical fiber's fiber core is optically connected to the waveguide's core, with the waveguide's width tapered to match the fiber core, minimizing light expansion and propagation loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the distance between the optical fiber core and the mirror is increased, then the optical element can be mounted on the substrate, but the light flux expands resulting in deterioration of optical coupling efficiency
Solution Approach 1:
An internal waveguide is introduced as an intermediary component between the optical fiber core and the mirror. The waveguide includes a core with a width that is smaller than the upper end of the first groove and substantially the same as the fiber core width. This intermediary structure guides the light flux from the fiber core to the mirror without allowing it to expand, thereby maintaining optical coupling efficiency while enabling the optical element to be mounted on the substrate.
2Loss of energy
If the core width of the internal waveguide is reduced to match the fiber core width, then optical coupling efficiency is improved, but the manufacturing precision requirement increases
Solution Approach 1:
The internal waveguide core is designed with a specific local quality: its width is controlled to be smaller than the upper end of the first groove and substantially the same as the fiber core width. This localized dimension control at the waveguide core ensures optimal optical coupling efficiency while the overall structure (including the first groove and second groove) provides tolerance for manufacturing variations.
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
This configuration enhances optical coupling efficiency by preventing light flux expansion and reducing propagation loss between the mirror and the fiber core, thereby improving signal transmission and reception efficiency.
Implementation Method 1
a mirror (reflection surface) 34 is formed on the front end of the other V-groove 32. This mirror 34 changes the optical axis of a core 33a of the optical fiber 33
Implementation Method 2
an internal waveguide provided within the first groove of the substrate... the core of the internal waveguide is tapered to form such slopes... the width between opposite side faces of the core becomes gradually smaller
Data Source
Figure 1
Figure 2A~2C
Figure 3A~3B
AI summary
Disclosed is an optical module which improves optical coupling efficiency either when configured to receive an optical signal from an optical fiber with a light receiving element or when configured to receive an optical signal from a light emitting element with an optical fiber. The optical module includes: a substrate (1) having in the surface thereof a first groove (1a) and a second groove (1b) formed, with this second groove (1b) being configured to have a substantially V-shaped cross section formed deeper than the first groove and being formed in continuation from the first groove; and an internal waveguide (16) provided within the first groove (1a) of the substrate (1). The optical further modules a mirror portion (15) for changing an optical path, provided at the front end of the first groove (1a); an optical element (12a) mounted on the surface of the substrate (1) so as to face the mirror portion (15), and configured to emit an optical signal to a core (17) of the internal waveguide (16) via the mirror portion (15). Moreover, the optical module further includes an optical fiber (2) having a fiber cladding (22) placed within the second groove (1b) and a fiber core (21) optically connected to the core (17) of the internal waveguide (16).