Multi-layer p-n junction phase shifter for low loss
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Solution Overview
Problem
Conventional optical phase shifters cause appreciable insertion loss and underutilize the rib region, with their size affecting performance and requiring miniaturization to fit in limited spaces of transmitter optical subassemblies.
Innovation Solution
The optical phase shifter design involves stacking alternating p- and n-doped layers in the rib region, electrically connecting the overlying doped layers, which extends the p-n interface, reducing insertion loss and minimizing the size of the phase shifter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional single-layer p-n junction design is used, then the device structure is simple, but insertion loss is high and rib region utilization is low
Solution Approach 1:
The single-layer p-n junction is segmented into multiple alternating p-doped and n-doped layers (e.g., p-n-p-n structure). This segmentation increases the total p-n interface area within the rib region, improving optical signal utilization and reducing insertion loss by distributing the optical interaction across multiple interfaces rather than relying on a single junction.
Solution Approach 2:
The invention transitions from a lateral p-n junction design to a vertical stacked multi-layer structure. By stacking doped layers vertically in the rib region and electrically connecting them through vertical contact regions, the patent creates a three-dimensional architecture that maximizes the use of vertical space and increases the effective optical path length within the constrained rib region footprint.
2Volume of moving object
If conventional phase shifter design is used, then the device occupies standard space, but it does not fit in limited spaces of transmitter optical subassemblies
Solution Approach 1:
The multi-layer p-n structure is nested within the existing rib region geometry. The alternating doped layers are stacked vertically within the same lateral footprint as conventional single-layer designs, effectively nesting multiple functional interfaces within the same spatial envelope. This nesting approach miniaturizes the device volume while maintaining or enhancing performance through increased interface area.
Solution Approach 2:
By exploiting the vertical dimension through stacked layers, the invention compresses the device footprint in the lateral plane while expanding functionality in the vertical direction. This dimensional transition allows the phase shifter to fit within limited TOSA spaces without sacrificing performance, as the optical interaction occurs across multiple vertical interfaces rather than requiring extended lateral dimensions.
3Productivity
If rib region is underutilized, then manufacturing is simpler, but optical signal propagation efficiency is reduced
Solution Approach 1:
The rib region is segmented into multiple functional layers with alternating doping types. Each p-n interface within the stacked structure serves as an independent optical interaction region, allowing the optical signal to experience phase modulation across multiple interfaces. This segmentation transforms the underutilized rib region into a series of active optical zones, thereby improving propagation efficiency without requiring external expansion.
Solution Approach 2:
The invention activates the vertical dimension of the rib region by stacking doped layers, converting previously unused vertical space into functional optical interaction zones. This dimensional exploitation ensures that light propagating through the rib region interacts with multiple doped interfaces, maximizing the utilization of the entire rib volume for optical signal modulation.
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 design reduces insertion loss, maximizes the use of the rib region for optical signals, and miniaturizes the phase shifter, enabling higher-speed and more functional optical devices with performance independent of light wavelength.
Implementation Method 1
the difference in refractive indices between the n-doped and p-doped regions allows an optical signal to propagate in a desired direction with minimal energy loss
Implementation Method 2
An electric field (e.g., RF signal) is applied across the terminals V+ and V− to shift the phase of the optical signal passing through the phase shifter
Data Source
AI summary
An optical phase shifter and a method of making the same are disclosed. The phase shifter includes a substrate, a p-doped electrode and an n-doped electrode on the substrate, a first doped semiconductor layer on the p-doped electrode or the n-doped electrode and in electrical contact with the other electrode, a second doped semiconductor layer on the first doped semiconductor layer, a first vertical region electrically connecting the second doped semiconductor layer with the one electrode, and a cladding layer on or over the second semiconductor layer, the first vertical region, and at least a first sidewall of each of the first and second semiconductor layers. The p-doped electrode and the n-doped electrode form a p-n junction at an interface therebetween. The first and second doped semiconductor layers have the same doping type as the other electrode and the one electrode, respectively.