Series-Connected Semiconductor Laser and Amplifier Drive Current Reduction
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Solution Overview
Problem
In semiconductor optical integrated devices with LD, EAM, and SOA integrated on a common substrate, the common drive voltage applied through a single terminal leads to uneven current distribution between LD and SOA, limiting the optical output and increasing power consumption, especially at high modulation speeds.
Innovation Solution
The semiconductor optical integrated device configures the n-side cladding layers of the LD and SOA to be electrically insulated, allowing for a series connection of the semiconductor laser and amplifier, reducing the drive current from the power supply and maintaining the conventional electrode structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the LD and SOA are connected and driven through the same terminal with common drive voltage, then the device structure is simple and ease of operation is maintained, but the current distribution is uneven and the total drive current increases excessively
Solution Approach 1:
The patent divides the common drive terminal into separate drive terminals for the LD and SOA. By providing independent drive terminals, the drive voltages and currents for each device can be controlled separately, allowing optimized current distribution that reduces total power consumption while maintaining simple operation through standardized terminal interfaces.
Solution Approach 2:
The patent applies different drive conditions to different parts of the system by providing separate drive terminals. This allows the LD and SOA to operate at their respective optimal current levels rather than sharing a common current, enabling local optimization of each device's operating point to reduce overall energy consumption.
2Illumination intensity
If the drive current of the LD is increased to compensate for EAM insertion loss, then the optical output increases, but the power consumption increases and the extinction characteristic deteriorates
Solution Approach 1:
The patent introduces an independent drive terminal for the SOA as an intermediary component. The SOA receives optimized drive current through its dedicated terminal, allowing it to compensate for EAM insertion loss and amplify the optical signal without requiring increased drive current from the LD, thus avoiding the trade-off between optical output and power consumption.
Solution Approach 2:
The patent changes the electrical drive parameters by providing separate drive terminals with independently controllable voltages and currents. This allows the SOA to be driven at its optimal current level to provide necessary optical amplification, while the LD operates at its optimal current level for laser generation, eliminating the need to increase LD current to compensate for losses.
3Speed
If the modulation speed increases to 10 Gb/s or more, then the communication speed improves, but the pattern effect becomes more pronounced and waveform degradation occurs
Solution Approach 1:
The patent applies preliminary action by providing independent drive terminals that enable pre-optimization of drive conditions before high-speed modulation. The separate terminals allow the LD and SOA to be driven with optimized current waveforms that anticipate and compensate for pattern effects, maintaining waveform quality at 10 Gb/s and above by preventing carrier density fluctuations from causing degradation.
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 enables a high output semiconductor optical integrated device with reduced drive current and power consumption, while maintaining the conventional driving method and electrode structure, effectively addressing the limitations of existing technologies.
Implementation Method 1
the n-side cladding layer of the semiconductor amplifier and the n-side cladding layer of each of the plurality of semiconductor lasers are electrically insulated
Implementation Method 2
configured such that holes are injected from a p-side cladding layer and electrons are injected from a n-side cladding layer into an active layer
Implementation Method 3
a semiconductor optical amplifier (SOA) is monolithically integrated on the same substrate on an EAM emission side of a device in which an LD and the EAM are integrated
Data Source
AI summary
A semiconductor optical integrated device comprises a semiconductor amplifier and a plurality of semiconductor lasers, wherein the semiconductor amplifier and the semiconductor lasers are monolithically integrated on a semiconductor substrate, an n-side cladding layer of the semiconductor amplifier and an n-side cladding layer of each of the semiconductor lasers are electrically insulated by an insulating layer formed between the semiconductor substrate and the n-side cladding layer of the semiconductor lasers and an insulating layer formed between the n-side cladding layer of the semiconductor amplifier and the n-side cladding layer of the semiconductor lasers, the n-side cladding layer of the semiconductor lasers and the p-side cladding layer of the semiconductor amplifier is configured to be electrically connected, and the semiconductor amplifier and each semiconductor laser of the plurality of semiconductor lasers are electrically connected in series.