Photodetector Saturation Mitigation via Dynamic Switching

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Solution Overview

Problem

High power laser application in magneto-optical defect center material sensors leads to photodetector saturation, reducing the speed at which the material can reset to a maximum polarization between excited and ground states, thereby decreasing the sensing capability.

Innovation Solution

A system comprising a magneto-optical defect center material, first and second optical excitation sources, and an optical detection circuit with a switch that activates between disengaged and engaged states to receive high intensity signals, preventing saturation of the photodetector and allowing the material to operate in a non-saturated state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If high power laser is applied to increase optical source output power, then the optical excitation intensity is improved, but the photodetector circuit becomes saturated and the reset speed decreases

Engineering Contradiction:

Improveoptical excitation intensityVSAvoidreset speed

Core Design Contradiction:

Illumination intensityVSSpeed

Solution Approach 1:

The patent applies a dynamic switching mechanism that changes the optical detection circuit configuration based on real-time signal intensity. The switch transitions between engaged and disengaged states depending on whether the signal exceeds a threshold, allowing the system to adapt its detection sensitivity dynamically. This resolves the contradiction by enabling high intensity measurement without permanent saturation while maintaining fast reset capability.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent employs periodic pulsed optical excitation rather than continuous illumination. By using periodic action with controlled duty cycles, the system can deliver high intensity excitation during active measurement windows while allowing the photodetector to reset during intervals between pulses. This periodic approach prevents cumulative saturation effects while maintaining sufficient excitation intensity for sensitive detection.

Inventive Principle:

Principle #19Periodic action

2Illumination intensity

If high power laser is applied to increase optical source output power, then the optical excitation intensity is improved, but the photodetector circuit saturation occurs

Engineering Contradiction:

Improveoptical excitation intensityVSAvoidphotodetector operation reliability

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The dynamic switching mechanism adjusts the photodetector circuit operation mode based on signal intensity conditions. When high intensity signals are detected, the switch transitions to protect the photodetector from saturation damage. This dynamic adaptation ensures reliable operation across varying signal conditions without compromising the ability to detect high intensity optical excitation.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent introduces a switching mechanism as an intermediary between the optical excitation source and the photodetector circuit. This intermediary component controls the signal flow and protects the photodetector from direct exposure to potentially saturating high intensity light while still allowing accurate measurement of the optical excitation intensity through controlled signal paths.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If switch is activated to prevent photodetector saturation, then the photodetector operates in non-saturated state, but the system complexity increases

Engineering Contradiction:

Improvephotodetector operation reliabilityVSAvoidoptical detection circuit complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the optical detection circuit into distinct operational modes controlled by a simple switch. The circuit is divided into paths for different signal intensity conditions, with the switch acting as a gate between these segments. This segmentation allows complex protection functionality to be achieved through relatively simple circuit architecture, minimizing the increase in overall system complexity while maintaining reliable photodetector operation.

Inventive Principle:

Principle #1Segmentation

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

The system effectively reduces repolarization time and maintains sensitivity by preventing photodetector saturation, enabling higher bandwidth operation without signal attenuation.

Implementation Method 1

Magneto-optical defect center materials, such as diamonds, Silicon Carbide (SiC), etc. can have sensitivity for magnetic field measurement

Methodology Applied

Scientific EffectMagneto-optical effect: Magneto-Optic Effects

Implementation Method 2

an optical detection circuit comprising a photocomponent, the optical detection circuit configured to activate a switch

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentUS10145910B2Photodetector circuit saturation mitigation for magneto-optical high intensity pulses

Publication Date: 2018.12.04 LOCKHEED MARTIN CORP

AI summary

A system activates a switch between a disengaged state and an engaged state, receives, via the second optical excitation source, a light signal includes a high intensity signal provided by the second optical excitation source, and causes at least one of the photocomponent or the optical detection circuit to operate in a non-saturated state responsive to the activation of the switch.