Compact OTDR Module with Nested Hermetic Can and Connector Guide
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Solution Overview
Problem
Fiber optic components face challenges in harsh environments due to fragile pigtails, high manufacturing costs, incompatibility with re-work processes, and alignment issues caused by thermal expansion mismatches, which hinder their reliability and maintenance in compact, ruggedized packages.
Innovation Solution
A compact optical time domain reflectometer (OTDR) device with a connector guide, beam splitter, collimating lens, and transparent carrier for precision alignment and easy connectorization, utilizing flip-chip bonding and materials with matching thermal expansion coefficients to ensure reliable and cost-effective fiber optic modules with sealed optical paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hermetic pass-thru of the fiber is used, then the fiber optic component can operate in harsh environments, but the manufacturing cost increases and package volume is consumed
Solution Approach 1:
The device is divided into separate functional modules: a hermetic sealed can containing OE devices, a separate connector guide assembly, and a transparent carrier. This segmentation allows the hermetic seal to be applied only where needed for environmental protection while keeping other parts accessible and manufacturable at lower cost.
Solution Approach 2:
The connector guide is nested within or coupled to the hermetic can structure, and the transparent carrier with optical components is nested within the connector guide. This nested arrangement provides hermetic protection for critical components while maintaining compact overall size and reducing package volume.
2Reliability
If a hermetic pass-thru of the fiber is used, then the fiber optic component can operate in harsh environments, but considerable package volume is consumed
Solution Approach 1:
The connector guide is nested within or coupled to the hermetic can structure, and the transparent carrier with optical components is nested within the connector guide. This nested arrangement provides hermetic protection for critical components while maintaining compact overall size and reducing package volume.
Solution Approach 2:
The optical components and fiber paths are arranged in a three-dimensional configuration that optimizes space utilization. The vertical stacking of components (OE devices in can, connector guide, transparent carrier) reduces the horizontal footprint and overall package volume.
3Reliability
If fiber optic connectors are permanently attached to components, then the optical path can be sealed from contamination, but re-work and replacement become difficult
Solution Approach 1:
The device is divided into separate functional modules: a hermetic sealed can containing OE devices, a separate connector guide assembly, and a transparent carrier. This segmentation allows the hermetic seal to be applied only where needed for environmental protection while keeping other parts accessible and manufacturable at lower cost.
Solution Approach 2:
The connector guide is designed to accept attachable fiber optic connectors that can be connected and disconnected. This dynamic connection approach maintains optical path sealing through proper design of the connector interface while enabling re-work and replacement of fiber connectors without replacing the entire component.
4Ease of manufacture
If OE devices with mismatched thermal expansion coefficients are used, then the component can be manufactured with standard materials, but alignment is difficult to maintain in non-temperature controlled environments
Solution Approach 1:
The design accounts for thermal expansion parameter changes by providing alignment tolerance and compensation mechanisms. The connector guide and mounting structures are designed to accommodate thermal movement while maintaining optical alignment within acceptable ranges across the operating temperature range.
Solution Approach 2:
The mechanical design incorporates alignment tolerance and compensation features that cushion against thermal expansion mismatches. The connector guide and mounting structures are designed with built-in flexibility or adjustment capability to maintain alignment despite temperature 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
Enables automated, precise measurement of fiber discontinuities within fiber optic links without disconnecting the link, reduces handling risks, and allows for simple pigtail replacement and alignment maintenance, enhancing reliability and reducing costs in harsh environments.
Implementation Method 1
a beam splitter disposed within the connector guide
Implementation Method 2
a collimating lens in alignment with the beam splitter
Implementation Method 3
an optical transmitter and optical receiver in alignment with the collimating lens
Implementation Method 4
an optical transmitter and optical receiver in alignment with the collimating lens
Implementation Method 5
a time domain reflectometry measurement is determined from a time difference between a sent and received signal
Data Source
AI summary
A system for creating an optical time domain reflectometer (OTDR) in a small package is described. This system allows the implementation of multiple channels of OTDR in package of similar size to existing fiber optic transceivers.