Dual Grating-Coupled Lasers for Redundant Transceiver Reliability
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Solution Overview
Problem
High-speed data transmission networks face reliability issues due to elevated temperatures and high laser bias currents in optical transceivers, leading to high failure rates and burn-in testing inefficiencies.
Innovation Solution
Implementing dual grating-coupled lasers with redundant operation capabilities, where two or more edge-emitting lasers share components and a common n-contact, allowing for automatic switching between active and backup lasers to extend lifespan and improve reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If single laser operation is used, then device complexity is reduced, but reliability deteriorates due to high failure rates under elevated temperatures and high bias currents
Solution Approach 1:
The system is divided into multiple independent laser units (first GCL and second GCL), each capable of independent operation. This segmentation allows redundancy where if one laser fails, the other can take over, thus improving reliability without requiring a completely different system architecture.
Solution Approach 2:
A backup laser is provided in advance before failure occurs. The system includes both a first GCL and a second GCL where one serves as the primary light source and the other as redundancy. This prior cushioning ensures that when the primary laser fails under high temperature or high current conditions, the backup is already in place to maintain operation.
2Reliability
If dual redundant lasers are implemented, then reliability is improved, but device complexity increases due to additional components and switching mechanisms
Solution Approach 1:
Multiple laser units share common components including the n-contact structure, substrate, and potentially control circuitry. By merging these supporting elements, the patent reduces the overall complexity increase that would normally accompany dual-laser implementation, while still maintaining the reliability benefits of redundancy.
Solution Approach 2:
The grating coupler structure serves multiple functions: it acts as the optical output interface for the laser, provides a platform for integrating additional photonic components, and enables both single and dual laser configurations. This multi-functionality reduces the need for separate dedicated components for each laser, thereby limiting the complexity increase.
3Power
If high bias currents are used, then laser output power is increased, but reliability deteriorates due to accelerated degradation and failure
Solution Approach 1:
A backup laser is prepared in advance that can take over when the primary laser degrades or fails due to high current operation. This allows the system to maintain high power output requirements while extending overall system lifespan through periodic replacement or failover to the backup unit.
Solution Approach 2:
The system allows for the degradation and eventual failure of one laser unit under high current conditions while the backup unit continues to operate. The failed unit can be discarded or replaced, while the system recovers by switching to the backup, thus maintaining power output capability over extended periods.
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 approach significantly increases burn-in yield rates and reduces failure rates, improving the long-term durability and reliability of optical transceivers by enabling seamless switching between redundant light sources.
Implementation Method 1
The first transmit grating coupler may be configured to redirect horizontally-propagating first light, received from the first laser cavity, vertically downward and out of the first GCL
Data Source
AI summary
In an example embodiment, a system includes a first grating-coupled laser (GCL) that includes a first laser cavity optically coupled to a first transmit grating coupler configured to redirect horizontally-propagating first light, received from the first laser cavity, vertically downward and out of the first GCL. The system also includes a second GCL that includes a second laser cavity optically coupled to a second transmit grating coupler configured to transmit second light vertically downward and out of the second GCL. The system also includes a photonic integrated circuit (PIC) that includes a first receive grating coupler optically coupled to a first waveguide and configured to receive the first light and couple the first light into the first waveguide. The PIC also includes a second receive grating coupler optically coupled to a second waveguide and configured to receive the second light and couple the second light into the second waveguide.