Optical Pulse Dispersion Measurement Without Pulse Interference
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Solution Overview
Problem
Existing dispersion measuring devices face challenges in accurately measuring the wavelength dispersion amount of a measurement object when optical pulses interfere with each other due to varying time differences caused by wavelength dispersion.
Innovation Solution
A dispersion measuring device and method that utilizes a spatial light modulator to generate optical pulses with controlled phase shifts, forming an optical pulse train with defined time differences to prevent interference, allowing accurate measurement of wavelength dispersion by detecting the temporal waveform of the optical pulse train.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical pulses with different center wavelengths are transmitted through a measurement object, then wavelength dispersion can be measured based on time difference changes, but the optical pulses may shift to approach each other and interfere with each other, preventing accurate measurement
Solution Approach 1:
The patent applies preliminary action by pre-setting different initial time differences between optical pulses with different center wavelengths before they enter the measurement object. The control unit determines the wavelength dispersion amount in advance based on the detected temporal waveform, and adjusts the time difference between pulses beforehand to ensure they do not overlap and interfere, thus preventing measurement errors caused by pulse interference.
2Measurement precision
If the time difference between optical pulses is reduced to increase measurement sensitivity, then measurement precision improves, but optical pulses may overlap and interfere with each other
Solution Approach 1:
The patent applies dynamics by making the time difference between optical pulses adjustable rather than fixed. The control unit dynamically adjusts the time difference between pulses with different center wavelengths based on the detected temporal waveform and calculated wavelength dispersion amount, optimizing the time difference to maintain measurement sensitivity while preventing pulse overlap and interference throughout the measurement process.
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
Enables precise measurement of wavelength dispersion by widening the time difference between optical pulses, preventing interference and ensuring accurate estimation of the dispersion amount regardless of its positivity or negativity.
Implementation Method 1
a spatial light modulator that presents the phase patterns output by the control unit... applying a predetermined phase shift for each wavelength to the initial pulsed light
Implementation Method 2
since the plurality of optical pulses are shifted by different times due to the wavelength dispersion of the measurement object, the time difference between the optical pulses changes
Data Source
AI summary
A dispersion measuring device includes a pulse forming unit, a light detection unit, a control unit, and an arithmetic operation unit. The control unit selectively outputs a first phase pattern and a second phase pattern. The pulse forming unit forms an optical pulse train from initial pulsed light, the optical pulse train including a plurality of optical pulses having a time difference from each other and having different center wavelengths from each other. The light detection unit detects a temporal waveform of the optical pulse train. The arithmetic operation unit estimates a wavelength dispersion amount of a measurement object based on a feature amount of the temporal waveform of the optical pulse train. When the first phase pattern is output, a pulse having a long center wavelength is generated first. When the second phase pattern is output, a pulse having a short center wavelength is generated first.