Monolithic Optical Amplifier with Phase Control
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Solution Overview
Problem
Conventional optical amplifier devices are too large and expensive due to the use of separate packaged semiconductor optical amplifier (SOA) and variable optical attenuator (VOA) components, which limits their ability to operate effectively over distances of 40km without forward error correction (FEC) and 80km with FEC, and fail to handle a wide range of input powers.
Innovation Solution
A compact optical amplifier device that monolithically integrates an SOA chip with a VOA, an optical combiner, and a phase change element, such as a Mach-Zehnder interferometer, on a single substrate, allowing for controlled phase changes to achieve constructive or destructive interference and adjust the gain, thereby reducing size and cost while enabling operation over longer distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate packaged SOA and VOA components are used, then the device can provide gain and attenuation functions, but the device size and cost increase
Solution Approach 1:
The patent combines the SOA and VOA functions into a single monolithic device structure. The phase change element is integrated within the same semiconductor substrate as the optical amplifier, eliminating the need for separate packaged components. This merging reduces device size while maintaining both gain and attenuation functionalities through the combined action of the optical amplifier and the phase change element.
2Adaptability or versatility
If separate packaged SOA and VOA components are used, then the device can provide gain and attenuation functions, but the manufacturing cost increases
Solution Approach 1:
The patent merges multiple functions into a single monolithic device that can be fabricated using standard semiconductor manufacturing processes. By integrating the phase change element and optical amplifier in one structure, the device eliminates the need for separate packaging, assembly, and testing of multiple components, thereby reducing manufacturing cost while maintaining full functional capability.
Solution Approach 2:
The monolithic device structure is designed to perform multiple functions - optical amplification, variable optical attenuation, and phase control - all within a single device. This multi-functionality eliminates the need for separate SOA and VOA components, reducing both manufacturing complexity and cost while maintaining adaptability for different transmission distances and input power ranges.
3Adaptability or versatility
If conventional separate packaged devices are used, then gain and attenuation can be provided, but the device cannot efficiently handle a wide range of input powers
Solution Approach 1:
The patent implements dynamic control of the optical signal through the phase change element, which can be adjusted in real-time to control the amount of light reaching the optical amplifier. This dynamic adjustment capability allows the device to handle a wide range of input powers effectively, preventing saturation and patterning effects while maintaining reliable operation across different transmission conditions.
4Length of moving object
If APD with FEC is used in receiver, then transmission distance can be extended, but the distance coverage is insufficient for 40km without FEC
Solution Approach 1:
The patent applies preliminary action by performing optical amplification and attenuation control at the transmitter side before the signal is transmitted through the fiber. The monolithic device pre-adjusts the signal characteristics to optimize performance for specific transmission distances, enabling 40km coverage without FEC and 80km with FEC by properly conditioning the signal before transmission rather than relying solely on receiver-side APD and FEC.
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
The solution enables the optical amplifier device to operate effectively over 40km without FEC and potentially 80km, meeting ER4 standards, while reducing size and cost by integrating multiple functions on a single substrate, and efficiently managing input power across a wide dynamic range.
Implementation Method 1
a phase change element located in the second optical path for changing the phase of a signal passing along the second optical path
Implementation Method 2
the phase change element being controllable so as to cause constructive and/or destructive optical interference at the optical combiner between signals from the first and second optical paths
Data Source
Figure 1~2
Figure 3~4
AI summary
An optical amplifier device, the device comprising: an input port for receiving an optical signal; an optical combiner; an optical amplifier for amplifying a signal output from the optical combiner to form an amplified signal at an output of the optical amplifier; a first optical path between the input and the optical combiner; a second optical path between the input and the optical combiner; and a phase change element located in the second optical path for changing the phase of a signal passing along the second optical path, the phase change element being controllable so as to cause constructive and/or destructive optical interference at the optical combiner between signals from the first and second optical paths and thereby alter the gain of the optical amplifier device.