Silicon Photonics Phase-Amplitude Tuning for Polarization Loss
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Solution Overview
Problem
Existing methods for coupling light between optical fibers and silicon photonics waveguides face significant signal loss due to polarization mismatch and require large optical interference circuits, increasing power consumption and circuit size.
Innovation Solution
Implement phase and amplitude tuning in the electrical module of an optoelectronic system, using feedback control signals to manage optical phase shift and amplitude in the electrical domain, eliminating the need for large optical interference circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If optical interference circuits (e.g., Mach-Zehnder interferometer modulators) are used to tune phase and amplitude of split optical signals, then phase and amplitude tuning capability is improved, but power consumption increases and circuit size increases
Solution Approach 1:
The patent replaces optical interference circuits with electrical domain processing. Specifically, it uses a 90-degree hybrid coupler to convert optical phase differences into amplitude differences, followed by photodetectors to convert optical signals to electrical signals. The in-phase and quadrature components are then processed electrically using adders and gain controllers to achieve the desired amplitude and phase tuning without requiring complex optical interference circuits, thereby reducing power consumption and circuit size.
Solution Approach 2:
The patent introduces a 90-degree hybrid coupler as an intermediary device that transforms the optical phase difference into amplitude modulation. This coupler acts as a mediator that converts the phase information from the two polarization components into in-phase and quadrature amplitude components, which can then be easily processed in the electrical domain using simple photodetectors and adders, avoiding the need for complex optical interference circuits.
2Ease of operation
If optical interference circuits (e.g., Mach-Zehnder interferometer modulators) are used to tune phase and amplitude of split optical signals, then phase and amplitude tuning capability is improved, but circuit footprint increases
Solution Approach 1:
The patent replaces bulky optical interference circuits with compact electrical domain processing components. By using a 90-degree hybrid coupler followed by photodetectors and electrical adders, the system achieves phase and amplitude tuning functionality with significantly reduced circuit footprint compared to traditional optical interference circuits like Mach-Zehnder interferometer modulators.
Solution Approach 2:
The patent extracts the phase and amplitude tuning functionality from the optical domain and relocates it to the electrical domain. By separating the optical signal splitting function (performed by the 90-degree hybrid coupler) from the tuning function (performed by photodetectors and electrical adders), the system eliminates the need for large optical interference circuits while maintaining the required tuning capability.
3Ease of manufacture
If direct coupling is used between optical fiber and waveguide, then coupling simplicity is improved, but signal loss increases due to dimension mismatch and polarization incompatibility
Solution Approach 1:
The patent introduces a 90-degree hybrid coupler as an intermediary device between the optical fiber and the waveguide. This coupler receives the optical signal and splits it into two components with a 90-degree phase difference, enabling the system to handle arbitrary polarization states. By combining this with polarization splitting grating couplers that separate TE and TM modes, the system achieves efficient coupling while maintaining signal integrity and reducing loss.
Solution Approach 2:
The patent implements dynamic phase and amplitude tuning capability to adapt to varying input conditions. The system uses controllable adders and gain controllers in the electrical domain to dynamically adjust the in-phase and quadrature components, allowing optimal signal recovery regardless of the input polarization state or phase conditions, thereby minimizing signal loss under varying operating conditions.
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
Reduces circuit footprint and power consumption by performing phase and amplitude tuning in the electrical module, ensuring efficient signal recovery without optical interference circuits.
Implementation Method 1
a polarization splitting grating coupler (PSGC) is needed to provide polarization light in either transverse magnetic (TE) or transverse magnetic (TM) polarization mode from the optical fiber to the waveguide
Implementation Method 2
Optical gratings are frequently used to couple light between an optical fiber and a silicon photonics waveguide
Implementation Method 3
tuning the phase and the amplitude of the received split optical signals may require optical interference circuits (e.g. Mach-Zehnder interferometer modulators)
Implementation Method 4
the first and second photodiodes converts the first and second components into first and second electrical signals
Data Source
AI summary
A silicon photonics integrated circuit includes a polarization splitting grating coupler (PSGC) configured to receive an optical signal and split the optical signal into two polarization components. The circuit includes a phase controller coupled to the PSGC, and the phase controller is configured to tune the split optical signal such that the two polarization components are in phase. The circuit includes a first and a second photodiode coupled to the phase controller, where the first photodiode receives a first component of the two polarization components and the second photodiode receives a second component of the two polarization components, and the first and second photodiodes converts the first and second components into first and second electrical signals, respectively. The circuit includes an amplitude controller coupled to the first and the second photodiodes, the amplitude controller configured to add the first and the second electrical signals to output a combined electrical signal.