Photonic Qubit Interface Using Optical Splitters to Reduce Cross-Talk

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Solution Overview

Problem

Conventional interfacing methods for qubits in quantum computers require multiple wires and suffer from cross-talk issues, making it difficult to efficiently deliver input signals and collect output signals in large-scale quantum systems.

Innovation Solution

A photonic integrated circuit with optical splitters and waveguides is used to split and distribute modulated optical carriers, converting them into electrical or electromagnetic signals for qubit operation, minimizing cross-talk and reducing the need for multiple wires.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional interfacing methods using one wire per port are used, then signal delivery to qubits is achieved, but the area required by wires and on-chip pads becomes massive and cross-talk between wires occurs

Engineering Contradiction:

Improvesignal integrityVSAvoidarea required by wires and on-chip pads

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

Multiple RF/microwave signals are merged onto a single optical carrier wave through modulation, allowing multiple qubit control signals to be transmitted through a shared optical interface rather than requiring separate physical wires for each signal

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

An optical carrier wave serves as an intermediary medium to transport multiple qubit control signals and readout signals between the microwave domain (qubit operations) and the electronic domain (signal processing), eliminating the need for direct microwave wiring

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If conventional interfacing methods using one wire per port are used, then signal delivery to qubits is achieved, but cross-talk between wires occurs

Engineering Contradiction:

Improvesignal isolationVSAvoidinterfacing structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The optical carrier wave acts as an intermediary that inherently isolates signals during transmission, preventing cross-talk between different qubit control lines while simplifying the interfacing structure

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The mechanical/electrical wiring system is replaced with an optical transmission system, substituting physical wire-based signal delivery with optical carrier-based delivery to eliminate wire-induced cross-talk

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If multiple RF/microwave pulses are delivered to many qubits, then qubit operations are controlled, but the number of required input and output signals becomes massive

Engineering Contradiction:

Improvequbit operation capabilityVSAvoidnumber of input and output signals

Core Design Contradiction:

ProductivityVSQuantity of substance

Solution Approach 1:

Multiple independent RF/microwave control signals intended for different qubits are merged onto a single optical carrier through frequency or time division multiplexing, reducing the number of physical signal channels required

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The optical carrier wave performs multiple functions simultaneously, serving as a transmission medium for both qubit control signals and readout signals, and can carry information for multiple qubits through modulation techniques

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 enables efficient signal delivery and collection for qubits, reducing the complexity and area requirements, while maintaining high signal integrity and minimizing noise.

Implementation Method 1

one or more optical splitters splitting a plurality of spectrally separated signals from a carrier (e.g., optical carrier) and outputting the signals to a plurality of outputs

Methodology Applied

Scientific EffectOptical splitting:

Implementation Method 2

a photonic integrated circuit comprising the splitters and one or more waveguides coupled to the splitters to transmit the carrier to the splitters

Methodology Applied

Scientific EffectWaveguide transmission: Waveguide (optics)

Implementation Method 3

a modulator modulating a carrier with the plurality of input signals having different frequencies to form the carrier

Methodology Applied

Scientific EffectModulation: Phase Modulation

Implementation Method 4

one or more detectors coupled to the outputs of the splitters and detecting each one of the signals, the detectors converting the signals to a plurality of electrical or electromagnetic signals

Methodology Applied

Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentUS12438250B2Methods and systems for providing quantum computer interface

Publication Date: 2025.10.07 CALIFORNIA INST OF TECH

AI summary

An interface for communicating with qubits, the interface including one or more splitters splitting a plurality of signals from a modulated optical carrier and outputting the signals to a plurality of outputs. In one example, the signals include a plurality of different input signals used for exciting or controlling the one or more qubits. In another example, the signals include a plurality of output signals received from the one or more qubits, wherein the output signals used to read one or more states of the one or more qubits.