Photonic Integrated Circuit SOA Layout for Shared-Laser Power Control
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Solution Overview
Problem
Optical transceivers with shared lasers face challenges in optimizing both transmit and local oscillator power, leading to suboptimal performance due to tradeoffs between signal-to-noise ratio and sensitivity, which are not simultaneously optimal.
Innovation Solution
A photonic integrated circuit with semiconductor optical amplifiers (SOAs) in both the transmitter and receiver portions, allowing for independent optimization of transmit and local oscillator power, and the use of variable optical attenuators to adjust signal power, enabling improved signal-to-noise ratio and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a shared laser is used for both transmitter and receiver portions, then device size is reduced and electrical power is decreased, but optimal transmit power and local oscillator power cannot be simultaneously achieved
Solution Approach 1:
The patent divides the optical signal path into separate transmitter and receiver portions, each with dedicated semiconductor optical amplifiers. This segmentation allows independent optimization of transmit power and local oscillator power, resolving the contradiction by enabling both functions to operate at optimal power levels simultaneously while still sharing a common laser source.
Solution Approach 2:
The patent applies local quality by providing dedicated semiconductor optical amplifiers in specific locations within the transmitter and receiver portions. Each amplifier is positioned to independently control and optimize the optical power at critical points in the signal path, allowing transmit and local oscillator powers to be optimized separately despite sharing a common laser.
2Use of energy by moving object
If a shared laser is used for both transmitter and receiver portions, then electrical power consumption is reduced, but sensitivity and signal-to-noise ratio cannot be simultaneously optimized
Solution Approach 1:
The patent segments the optical power control functions by placing dedicated semiconductor optical amplifiers in both the transmitter and receiver portions. This allows independent optimization of transmit power and local oscillator power, enabling both to operate at optimal levels while still using a single shared laser, thus maintaining low electrical power consumption while improving sensitivity.
Solution Approach 2:
The patent utilizes parameter changes by controlling the gain of semiconductor optical amplifiers through electrical current adjustment. By varying the bias current to the SOAs, the optical power output can be precisely controlled, allowing optimization of both transmit and local oscillator powers independently while maintaining efficient operation of the shared laser.
3Device complexity
If tradeoffs are made between transmit and local oscillator power, then device complexity is reduced, but neither transmit nor receive performance is optimal
Solution Approach 1:
The patent segments the power control architecture by implementing dedicated semiconductor optical amplifiers in both transmitter and receiver portions. This segmentation eliminates the need for power tradeoffs by allowing independent optimization of transmit and local oscillator powers, achieving optimal performance in both functions simultaneously while maintaining relatively simple device architecture.
Solution Approach 2:
The patent applies local quality by positioning semiconductor optical amplifiers at specific locations within the optical circuit to independently control power levels. This localized power control enables both transmit and receive paths to operate at optimal power levels without requiring complex global power management or compromising device simplicity.
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 enhances the signal-to-noise ratio and sensitivity by allowing for dynamic control of local oscillator power, optimizing performance beyond the limitations of the shared laser, and maintaining higher optical power throughout the circuit, thus overcoming noise limitations and preserving spectral quality.
Implementation Method 1
A first semiconductor optical amplifier is provided in the transmitter portion, such that an output of the transmitter portion is greater than an output of the transmitter portion in an absence of the first semiconductor optical amplifier
Implementation Method 2
A second semiconductor optical amplifier or variable optical attenuator is provided in the receiver portion to adjust a power of an optical input to the photodiode circuit
Implementation Method 3
the receiver portion includes a photodiode circuit
Data Source
AI summary
Consistent with the present disclosure, a transceiver is implemented as a photonic integrated circuit (PIC) that includes a transmitter and a receiver. A laser is also provided that provides light to a splitter, which supplies a first portion of the light to the transmitter and a second power of the light to the receiver. Semiconductor optical amplifiers (SOAs) are provided at one or more locations on the PIC. In one example, at least one SOA is provided in the transmitter so that the transmitted optical signal has a desired power, and at least another SOA is provided in the receiver so that the local oscillator signal has a desired power. In a further example, an SOA is provided in the receiver to boost the power of the received optical signal. Preferably, the transceiver, including the SOAs, is monolithically integrated on a substrate, such as a substrate including indium phosphide (InP). Moreover, the SOA can be readily controlled via a low voltage current source consuming minimal electrical power.