Quantum Optical Module Thermal Layout for Stable PIC Operation

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Solution Overview

Problem

Existing quantum communication systems face challenges in maintaining the stability of photonic integrated circuits (PICs) due to temperature fluctuations, which can lead to noise and reduced key distribution rates in quantum key distribution (QKD) systems.

Innovation Solution

The implementation of a quantum communication system with an optical module that includes a temperature control element (TCE) and an interposer chip, which routes electric signals and provides thermal conductivity between the PIC and the TCE, actively stabilizing the temperature of the PIC.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If photonic integrated circuits are used in quantum communication systems, then key distribution capability is enabled, but temperature fluctuations cause noise and reduce key distribution rates

Engineering Contradiction:
Improvekey distribution rateVSAvoidtemperature stability
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

A thermally-isolated region is introduced as an intermediary structure between the PIC and the surrounding environment. This region acts as a thermal barrier that mediates heat transfer, allowing the PIC to maintain a stable temperature despite external temperature fluctuations, thereby reducing noise and improving key distribution rates

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If temperature control elements are added to stabilize PIC temperature, then temperature stability is improved, but device complexity increases

Engineering Contradiction:
Improvetemperature stabilityVSAvoidmodule structure complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The temperature control element is merged with the housing structure of the optical module. The housing itself is designed to provide thermal isolation and control, combining the structural support function with the temperature control function. This integration reduces the number of separate components and simplifies the overall device structure while maintaining effective temperature stability

Inventive Principle:
Principle #5Merging (Combining)

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 solution effectively reduces temperature-induced noise and drifts in the PIC, enhancing the reliability and performance of quantum communication systems by maintaining optimal operating conditions for the PIC.

Implementation Method 1

an interposer chip, which routes electric signals and provides thermal conductivity between the PIC and the TCE

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4001981B1An optical module, a system, a sending unit, a receiving unit, and a quantum communication system
Publication Date: 2025.04.30 KK TOSHIBA
  • EP4001981B1 patent drawingFigure 1
  • EP4001981B1 patent drawingFigure 2(a)~2(b)
  • EP4001981B1 patent drawingFigure 3

AI summary

An optical module comprising: a quantum photonic integrated circuit; a temperature control element; and a housing configured to house said photonic integrated circuit and said temperature control element, wherein the photonic integrated circuit is attached to the temperature control element, such that said photonic integrated circuit is in thermal communication with said temperature control element; and the temperature control element is attached directly to the housing, such that said temperature control element is in direct thermal communication with the housing.