Photonic Raster Multiplexing for Synchronized Waveguide Routing
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Solution Overview
Problem
Existing photonic circuits face challenges in efficiently rearranging and synchronizing photons spatially onto different waveguides to achieve concurrent arrival at a particular location, which is crucial for various operations in quantum computing and photonic systems.
Innovation Solution
Implementing a raster multiplexing technique in photonic circuits using an optical switching network with active optical switches and control logic to selectably route input photons to output waveguides in a fixed order, incorporating delay lines to synchronize photon arrival times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If photons are propagated through different waveguides at different times, then spatial rearrangement and synchronization are required, but this increases device complexity and operational difficulty
Solution Approach 1:
The patent implements a raster scanning approach where output waveguides are selected in a fixed periodic order (0, 1, 2, ..., R-1, 0, 1, ...) across time bins. This periodic selection pattern simplifies control logic by eliminating the need for complex dynamic routing decisions, as the output waveguide sequence is predetermined and repeats cyclically.
Solution Approach 2:
The system pre-determines the output waveguide selection sequence before photons arrive. The control logic is configured with a fixed raster pattern that specifies which output waveguide will be active in each time bin, allowing advance preparation of control signals and simplifying real-time operation.
2Productivity
If multiple output waveguides are used to improve photon throughput, then synchronization of photon arrival times becomes more difficult, reducing operational efficiency
Solution Approach 1:
The patent introduces delay lines as intermediary components between the optical switching network and output waveguides. These delay lines compensate for timing differences by introducing controlled delays to photons traveling through different paths, ensuring that photons from multiple input waveguides arrive simultaneously at their designated output waveguides.
Solution Approach 2:
The system organizes photon routing into discrete time bins with a periodic raster scanning pattern. By processing photons in synchronized time slots and repeating the raster pattern cyclically, the system maintains temporal organization across multiple waveguides, enabling efficient throughput while preserving synchronization.
3Ease of operation
If a fixed order raster selection method is used to simplify control logic, then flexibility in routing specific photons to specific outputs is reduced
Solution Approach 1:
The control logic uses a predetermined periodic raster pattern to select output waveguides in a fixed sequence. This approach simplifies the control mechanism by eliminating complex real-time decision-making, while the periodic nature of the pattern ensures systematic coverage of all output waveguides over time.
Solution Approach 2:
The system allows photons to be routed based on their arrival time and the current position in the raster sequence, rather than requiring active selection for each individual photon. The fixed raster pattern inherently determines routing decisions, reducing the need for complex adaptive control while maintaining systematic photon distribution across outputs.
Data Source
AI summary
Circuits and methods that implement multiplexing for photons propagating in waveguides are disclosed, in which an input photon received on a selected one of a set of input waveguides can be selectably routed to one of a set of output waveguides. The output waveguide can be selected on a rotating or cyclic basis, in a fixed order, and the input waveguide can be selected based at least in part on which one(s) of a set of input waveguides is (are) currently propagating a photon.