TOSA Feedthrough with Integrated Mounting Surfaces
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Solution Overview
Problem
Optical transceiver modules face challenges in scaling beyond four channels due to space constraints, thermal management, and RF signal integrity, particularly in hermetically-sealed housings, which increase manufacturing complexity and cost.
Innovation Solution
A multi-channel transmitter optical subassembly (TOSA) design utilizing a feedthrough device with integrated mounting surfaces within the hermetically-sealed housing, allowing for efficient mounting of laser diode drivers and filtering capacitors, which reduces the housing length and enables thermal isolation, thereby improving thermal dissipation and RF signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hermetically-sealed housings are used to ensure optical performance, then reliability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The feedthrough device is integrated within the hermetically-sealed housing structure, with mounting surfaces nested inside the housing cavity. This allows driver chips and capacitors to be mounted within the sealed environment, maintaining optical performance while simplifying the overall device structure and manufacturing process.
2Productivity
If more channels are integrated to increase transmission capacity, then productivity is improved, but space constraints and thermal management become more difficult
Solution Approach 1:
The feedthrough device utilizes the vertical dimension within the housing cavity by extending from the housing wall inward, creating mounting surfaces at different depths. This three-dimensional arrangement allows multiple driver chips and capacitors to be stacked or arranged vertically, increasing channel capacity without proportionally increasing the housing footprint.
Solution Approach 2:
Multiple functional components (driver chips, capacitors, mounting surfaces) are nested within the feedthrough device structure and housing cavity, allowing compact arrangement of multiple channels in a confined space, thereby increasing transmission capacity without linearly increasing housing volume.
3Reliability
If driver chips and capacitors are mounted inside the hermetically-sealed housing, then RF signal integrity is improved, but thermal dissipation becomes more challenging
Solution Approach 1:
The feedthrough device acts as an intermediary structure that provides mounting surfaces for heat-generating components while maintaining the hermetic seal. It serves as a thermal interface between the internal components and the external environment, allowing heat dissipation paths to be established without compromising RF signal integrity within the sealed housing.
Data Source
AI summary
The present disclosure is generally directed to a multi-channel TOSA arrangement with a housing that utilizes a feedthrough device with at least one integrated mounting surface to reduce the overall dimensions of the housing. The housing includes a plurality of sidewalls that define a hermetically-sealed cavity therebetween. The feedthrough device includes a first end disposed in the hermetically-sealed cavity of the housing and a second end extending from the cavity away from the housing. The feedthrough device provides the at least one integrated mounting surface proximate the first end within the hermetically-sealed cavity. At least a first laser diode driver (LDD) chip mounts to the at least one integrated mounting surface of the feedthrough device. A plurality of laser arrangements are also disposed in the hermetically-sealed cavity proximate the first LDD chip and mount to, for instance, a LD submount supported by a thermoelectric cooler.