Angled Semiconductor Chip Mounting for Optical Module Alignment
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Solution Overview
Problem
High-bit-rate optical communication systems require longer reach and lower wavelength chirping, which existing semiconductor optical communication modules with bent waveguides fail to achieve efficiently due to increased module size and risk of lens assembly contact during alignment.
Innovation Solution
A semiconductor optical communication module design with a semiconductor chip mounted at an acute angle to the carrier edge, allowing a parallel lens assembly placement that minimizes module size and prevents contact during optical axis adjustment, utilizing a bent waveguide structure that reduces back-reflection and wavelength chirping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a bent waveguide structure is used to suppress back-reflection, then wavelength chirping is reduced, but the lens assembly must be placed at an angle to the chip carrier which increases module size
Solution Approach 1:
The semiconductor chip is mounted at an acute angle (e.g., 45 degrees) relative to the chip carrier edge, creating an asymmetric configuration. This asymmetric mounting allows the bent waveguide to function properly for suppressing back-reflection and reducing wavelength chirping, while the lens assembly remains parallel to the chip carrier edge, avoiding the need for angled placement that would increase module size.
Solution Approach 2:
The invention changes the dimensional relationship between components by orienting the semiconductor chip at an acute angle to the carrier edge rather than using a conventional parallel alignment. This dimensional reconfiguration allows the optical axis to extend from the front facet through the bent waveguide to the lens assembly in a manner that maintains parallelism between the lens assembly and carrier edge, thus reducing module footprint.
2Reliability
If the lens assembly is placed at an angle to the chip carrier for bent waveguide alignment, then back-reflection is suppressed, but the lens assembly may strike the carrier end during optical axis adjustment
Solution Approach 1:
The asymmetric mounting of the semiconductor chip at an acute angle to the chip carrier edge enables the optical axis to be oriented such that the lens assembly can be positioned parallel to the carrier edge. This asymmetric configuration provides sufficient clearance between the lens assembly and carrier end, eliminating the risk of contact during optical axis adjustment while maintaining effective back-reflection suppression through the bent waveguide structure.
3Ease of manufacture
If the semiconductor chip is mounted with front facet closer to signal line, then electrical connection is simplified, but chip orientation becomes more complex
Solution Approach 1:
The semiconductor chip is mounted in an asymmetric orientation with the front facet positioned at an acute angle to the chip carrier edge and closer to the signal line. This asymmetric placement simplifies electrical connection by reducing the length of signal lines and improving signal integrity, while the acute angle orientation itself becomes a standardized design feature that manages the complexity through consistent geometric relationships.
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 module design achieves a smaller size, reduced wavelength chirping, and improved optical transmittance and electrical reflectance characteristics, enhancing the communication system's reach and performance.
Implementation Method 1
suppress back-reflection at the electroabsorber end facet. If modulated light is reflected back at the electroabsorber end facet, it reenters the laser diode
Implementation Method 2
An optical waveguide in the semiconductor chip transmits an optical signal that propagates on an optical axis extending from the front facet of the semiconductor chip to the end of the lens assembly
Implementation Method 3
a lens assembly having an end parallel to and facing the edge of the carrier
Data Source
AI summary
A semiconductor optical communication module includes a semiconductor chip mounted on a chip carrier and a lens assembly having an end parallel to and facing the front edge of the chip carrier. The semiconductor chip has a front facet oriented at an acute angle to the front edge of the chip carrier. An optical waveguide in the semiconductor chip transmits an optical signal that propagates on an optical axis extending from the front facet of the semiconductor chip to the end of the lens assembly. The optical axis is orthogonal to the end of the lens assembly and the front edge of the chip carrier. The angled mounting of the semiconductor chip on the chip carrier allows the lens assembly to be placed close to the edge of the chip carrier, and to be moved for optical axis adjustment without striking the chip carrier.