Planar Waveguide Laser with Chamfered Substrate Recess
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Solution Overview
Problem
Conventional planar waveguide solid-state laser devices face issues with uneven end facets during optical polishing, leading to increased optical loss, and the coating surface often comes off during cutting, resulting in decreased production yield and difficulty in handling hygroscopic laser media due to moisture absorption.
Innovation Solution
A planar waveguide solid-state laser device with a substrate having a chamfered recess at the end facet and a coating that continuously covers the end facet, preventing surface deflection and enhancing adhesion, thereby reducing optical loss and allowing storage in normal environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If optical polishing is performed on the end facet of the waveguide, then the surface smoothness is improved, but the end facet angle increases causing surface deflection
Solution Approach 1:
The substrate is prepared with a chamfered recess structure before the waveguide is assembled and polished. This preliminary structural preparation ensures that during subsequent optical polishing, the polishing pressure is distributed evenly and the end facet maintains its perpendicularity, preventing angle increase while achieving surface smoothness.
2Reliability
If the waveguide is cut after coating is applied, then the coating surface adhesion is tested, but the coating surface comes off resulting in decreased production yield
Solution Approach 1:
The coating is applied to extend onto the upper surface of the waveguide before cutting occurs. This preliminary extension creates a larger bonded area between the coating and waveguide, so that when cutting happens afterward, the coating maintains strong adhesion and does not come off, ensuring both reliability and productivity.
3Reliability
If a hygroscopic material is used as the laser medium, then the laser characteristics can be improved, but moisture absorption occurs requiring humidity-controlled environment
Solution Approach 1:
The coating extends onto the upper surface of the waveguide, forming a protective film that covers the interface between the waveguide and the external environment. This extended coating layer acts as a moisture barrier, preventing hygroscopic laser medium materials from absorbing moisture, thus allowing them to be used without requiring humidity-controlled environments.
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 solution prevents surface deflection and coating detachment, reduces optical loss, and facilitates stable manufacturing and storage of hygroscopic laser media in normal environments.
Implementation Method 1
Planar waveguide lasers have a structure in which the upper and lower surfaces of a thin planar laser medium extending in the oscillation direction of laser light are sandwiched between cladding layers having a lower refractive index than that of the laser medium, and in which the laser medium serves as a waveguide
Implementation Method 2
cladding layers having a lower refractive index than that of the laser medium, and in which the laser medium serves as a waveguide
Data Source
Figure 1A~1B
Figure 2A~2H
Figure 3A~3B
AI summary
In a planar waveguide laser device (1), a substrate (6) is joined to the upper surface of a waveguide (2). A recess (6a) having a chamfered shape is formed along an edge of an end facet of the substrate (6) on the side of the waveguide (2), the end facet being perpendicular to the direction of laser oscillation. An end facet of the waveguide (2) perpendicular to the oscillation direction of laser light is covered with a coating (7). A wraparound portion (7a) continuing from the coating (7) covers the upper surface of the waveguide (2) facing the recess (6a) of the substrate (6).