Optical Transceiver SOA Preamplifier Branch Scaling
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Solution Overview
Problem
Conventional WDM-based silicon photonic integrated circuits face limitations in increasing the number of branches due to the need for higher laser output power, which leads to increased power consumption and size, and the total transmission capacity is restricted by the sensitivity of photo detectors and transmission loss.
Innovation Solution
Incorporating a semiconductor optical amplifier (SOA) preamplifier in the receiving-side integrated optical circuit to collectively amplify WDM signal lights before wavelength separation, reducing the required laser output power and minimizing overall power consumption by distributing optical gain across multiple branches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of branches is increased to supply more signal lights from a single laser source, then the total transmission capacity is improved, but the laser output power must be increased to N times greater which exceeds the limits of available semiconductor laser sources
Solution Approach 1:
The patent applies preliminary action by introducing a semiconductor optical amplifier (SOA) that performs optical amplification before the wavelength division multiplexing process. This pre-amplification compensates for the power loss that would occur if laser output power were increased, allowing the system to support more branches without requiring proportionally higher laser power. The SOA is positioned to amplify signals at an appropriate stage in the transmission path, enabling the system to achieve higher transmission capacity while maintaining manageable power levels.
2Productivity
If the number of branches is increased to expand transmission capacity, then the total transmission capacity is improved, but the power consumption of the entire optical transmission system increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the drive current of the semiconductor optical amplifier to control its optical gain. The control circuit monitors the actual output power of the laser and the required transmission capacity, then adjusts the SOA drive current accordingly. This dynamic parameter adjustment allows the system to optimize power consumption by ensuring the SOA provides exactly the necessary amplification, avoiding both under-amplification and excessive power consumption. The parameter change approach enables efficient scaling of transmission capacity while maintaining optimal power usage.
3Reliability
If the output level of the laser is increased to N times greater to compensate for the minimum sensitivity of photo detectors and transmission loss, then error-free transmission is achieved, but the laser output power exceeds the limits of available semiconductor laser sources
Solution Approach 1:
The patent introduces a semiconductor optical amplifier as an intermediary device between the laser source and the wavelength division multiplexer. The SOA serves as a mediator that provides the necessary optical amplification without requiring the laser itself to operate at excessively high power levels. By placing the amplifier in the transmission path, it compensates for the power loss from branching and component insertions, ensuring sufficient signal strength reaches the photo detectors for error-free transmission while keeping the laser operating within its safe and efficient power range.
4Productivity
If the number of laser arrays is increased to achieve desired total transmission capacity, then the total transmission capacity is improved, but the cost and device size increase
Solution Approach 1:
The patent applies universality by using a single semiconductor optical amplifier to serve multiple wavelength channels simultaneously. Rather than requiring separate amplification stages for each wavelength or multiple independent laser arrays, the SOA provides unified optical amplification across all wavelengths in the WDM signal. This multi-functional approach allows the system to achieve high transmission capacity with fewer discrete components, reducing overall device size and complexity while maintaining the ability to handle multiple wavelength channels efficiently.
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 configuration allows for an increase in the number of branches without increasing laser output power, resulting in reduced total power consumption and efficient transmission capacity expansion, with a 13% reduction in power consumption when the number of branches is sixteen compared to conventional structures.
Implementation Method 1
amplifying the wavelength division multiplexed signal using an optical amplifier before wavelength separation is performed
Implementation Method 2
detecting an intensity of a separated signal light of each wavelength
Data Source
AI summary
A receiving-side integrated optical circuit of an optical transceiver has an optical wavelength demultiplexer to separate signal light components of the different wavelengths contained in a wavelength division multiplexed signal received from each of N links of a transmission path, a set of N optical amplifiers inserted between the transmission path and the optical wavelength demultiplexer, each optical amplifier being configured to collectively amplify the signal light components of the different wavelengths contained in the received wavelength division multiplexed signal, and a set of photo detectors arranged after the optical wavelength demultiplexer and to detect the signal light components of the different wavelengths.