Photonic Quantum Clock Recovery Using Excess Pump Photons
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Generating an accurate system clock for photonic quantum computers is challenging due to the need for precise timing control of optical elements, as recovering the clock from photon streams would destroy the qubits, and existing methods using electrical signals or heralding signals are unsuitable due to phase errors and non-deterministic nature.
Innovation Solution
A system is developed to generate clock signals for photonic quantum computing systems by converting excess pump photons into electrical pulses using a photodetector and clock generator, located within the cryostat, to create a stable clock signal for precise timing control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrical signals or heralding signals are used to generate clock signals, then clock generation is possible, but phase errors occur or the process becomes non-deterministic
Solution Approach 1:
The patent uses excess pump photons as an intermediary to generate clock signals. Instead of directly using electrical signals or heralding signals which cause phase errors or non-deterministic behavior, the system converts excess pump photons into optical clock signals through a photodetector. This intermediary approach maintains deterministic timing while avoiding the phase errors associated with electrical signal methods.
Solution Approach 2:
The patent changes the parameter domain from electrical signals to optical signals for clock generation. By converting excess pump photons (optical domain) into clock signals through photodetection, the system achieves deterministic timing behavior and phase stability that were not attainable with electrical signals alone.
2Loss of information
If the clock is recovered from photon streams, then timing information is obtained, but the qubits are destroyed
Solution Approach 1:
The patent segments the pump photon stream into two distinct用途: signal photons for quantum computation and excess pump photons for clock generation. By separating these functions, the system can extract timing information from the excess pump photons without affecting the integrity of the signal photons that carry quantum information.
Solution Approach 2:
The excess pump photons serve as an intermediary carrier for timing information. Instead of measuring the signal photons directly (which would destroy them), the system uses the excess pump photons as a mediator to extract clock signals, thereby preserving the qubits while still achieving accurate timing recovery.
3Device complexity
If photodetector and clock generator are located outside the cryostat, then system complexity is reduced, but timing synchronization deteriorates
Solution Approach 1:
The patent uses optical coupling through a waveguide as an intermediary mechanism to connect the photodetector inside the cryostat with the clock generator outside. This optical intermediary allows timing synchronization to be maintained across the cryostat boundary without requiring complex electrical connections or compromising the cryogenic environment.
Solution Approach 2:
The patent replaces mechanical/electrical coupling with optical coupling for signal transmission across the cryostat boundary. By using optical waves instead of electrical signals or mechanical connections, the system achieves better timing synchronization while simplifying the interface between the cryogenic and ambient environments.
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 approach provides a stable and precise system clock within the cryostat, reducing phase errors and enabling efficient timing control for photonic quantum computing operations.
Implementation Method 1
a photodetector disposed inside the cryostat and configured to receive the second portion of each pump photon pulse of the plurality of pump photon pulses and generate a plurality of electrical pulses by converting the second portion of each pump photon pulse of the plurality of pump photon pulses into a respective electrical pulse of the plurality of electrical pulses
Implementation Method 2
a photon-pair source disposed inside the cryostat and optically coupled to the pump photon source via a waveguide. The photon-pair source is configured to receive the plurality of pump photon pulses via the waveguide, convert a first portion of each of a subset of the plurality of pump photon pulses into a photon pair
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
A system for generating clock signals for a photonic quantum computing system includes a pump photon source configured to generate a plurality of pump photon pulses at a first repetition rate, a waveguide optically coupled to the pump photon source, and a photon-pair source optically coupled to the first waveguide. The system also includes a photodetector optically coupled to the photon-pair source and configured to generate a plurality of electrical pulses in response to detection of at least a portion of the plurality of pump photon pulses at the first repetition rate and a clock generator coupled to the photodetector and configured to convert the plurality of electrical pulses into a plurality of clock signals at the first repetition rate.