Eye Safety in Parallel Optical Transceivers
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Solution Overview
Problem
In parallel optical transceivers, a fault in one optical fiber often leads to the shutdown of the entire link, as existing solutions require disabling all channels except a single safety channel, resulting in link loss, which is undesirable as it does not allow some optical lanes to remain open.
Innovation Solution
A pluggable electro-optical module with optical receiver lane signal detection circuitry and transmit lane control circuitry that detects signal loss and switches corresponding transmit lanes to an eye-safe signaling mode, allowing individual lanes to remain operational while ensuring eye safety by transmitting a beacon signal of predetermined format.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If all channels except a single safety channel are shut down upon fault detection, then eye safety is ensured, but the entire link is lost and productivity decreases
Solution Approach 1:
The patent divides the parallel optical link into independent channel units, where each transmit lane can be independently controlled and monitored. When a fault is detected on one receive lane, only the corresponding transmit lane is switched to eye-safe mode, while other lanes continue normal operation. This segmentation allows the system to maintain partial link functionality rather than shutting down the entire link.
Solution Approach 2:
The patent applies different operational modes to different lanes based on their individual status. Normal lanes operate at full power for optimal performance, while the faulty lane operates in eye-safe beacon mode. This local differentiation of operational quality ensures that eye safety is maintained at the specific location of the fault without compromising the overall link performance.
2Reliability
If maximum power is transmitted from each VCSEL to maintain signal quality, then communication reliability improves, but eye safety limits are exceeded if fiber is damaged
Solution Approach 1:
The patent implements dynamic power control where each transmit lane can switch between two power states: normal high-power mode for reliable communication and low-power eye-safe beacon mode for safety. The system continuously monitors receive lanes and dynamically adjusts the corresponding transmit lane's power output based on signal quality and fault detection, optimizing both reliability and safety in real-time.
Solution Approach 2:
The patent changes the optical power parameter of the transmit lane based on the operational state. During normal operation, the transmit lane operates at maximum power to ensure signal quality. Upon detecting a fault on the corresponding receive lane, the system changes the power parameter to a reduced eye-safe level, transmitting only low-power beacon signals that maintain safety while allowing fault detection.
3Object-affected harmful factors
If a single fault triggers shutdown of all channels, then safety is ensured, but device complexity increases due to complete link loss
Solution Approach 1:
The patent segments the link management into independent per-lane control units. Each transmit lane has its own control circuitry that independently monitors its corresponding receive lane and adjusts its own operational state. This segmentation simplifies the overall system architecture by avoiding the need for complex centralized control that would manage complete link shutdowns, while still ensuring safety through distributed autonomous lane-level decision-making.
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 solution enables individual optical lanes to remain operational even if one fiber is broken, maintaining link functionality while ensuring eye safety by controlling transmit lanes to an eye-safe mode, thus preventing the entire link from being lost due to a single fiber fault.
Implementation Method 1
A typical parallel optical transceiver consists of a vertical cavity surface emitter laser (VCSEL) array, to provide N optical beams
Implementation Method 2
a photodiode array, to provide N parallel optical receiver lanes
Data Source
AI summary
An electro-optical transceiver module having at least one parallel optical transmit lane and at least one parallel optical receiver lane, the module comprising optical receiver lane signal detection circuitry to detect a loss of signal on one or more of the receive lanes, and optical transmit lane control circuitry to control a optical transmit lane corresponding to the receive lane, on which a loss of signal was detected to transmit a signaling mode optical signal indicating the loss of signal on the receive lane. In a multiple lane parallel optic embodiment, and by signaling a loss of a signal on a per lane basis, a break or fault in a sub-set of fibers of a parallel optical link will not result in the entire parallel optic link being lost.