Electro-Optic Modulators for High-Frequency Pulse Selection
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Solution Overview
Problem
Conventional optical pulse selection methods, such as Pockels cells, acousto-optical modulators, and electro-optical modulators, face limitations in achieving high repetition frequencies and short pulse widths due to high voltage requirements and complex adjustments, leading to inefficient pulse modulation and limited modulation frequency.
Innovation Solution
The method involves using a pair of electro-optic modulators with asymmetrical edge steepness, where one modulator switches from transparency to absorption more steeply than the other, allowing for improved edge steepness and efficient pulse selection by controlling the optical waveguide's transparency and absorption states, enabling high selective intensity with moderate continuous load and heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional electro-optical modulators are used for pulse selection, then pulse modulation is achieved, but the modulation frequency is limited and edge steepness is insufficient
Solution Approach 1:
The patent divides a single modulator into two separate electro-optical modulators (first and second modulators) with different edge steepness characteristics. This segmentation allows each modulator to be optimized for specific switching edges, enabling higher modulation frequencies and steeper edge transitions without increasing individual modulator complexity
Solution Approach 2:
The patent employs asymmetry by using two modulators with deliberately different edge steepness characteristics. The first modulator provides a steep leading edge while the second provides a steep trailing edge, creating an asymmetric pulse shaping approach that overcomes the limitations of symmetric conventional modulators
2Strength
If high voltage is applied to Pockels cells for pulse selection, then pulse transmission is achieved, but the achievable minimum pulse width and maximum repetition frequency are severely limited
Solution Approach 1:
The patent changes the operational parameters by using two modulators with different voltage-time characteristics instead of a single high-voltage modulator. This allows achieving the same optical transmission control with reduced voltage requirements and faster switching times, thereby reducing minimum pulse width
3Force
If acousto-optical modulators are used for pulse selection, then pulse deflection is achieved, but the repetition frequency is limited to not much more than 10 MHz
Solution Approach 1:
The patent replaces the mechanical/acoustic field-based acousto-optical modulation with an electro-optical approach using two fast-switching modulators. This substitution eliminates the limitations of acoustic wave buildup time and enables repetition frequencies well above 10 MHz
4Volume of moving object
If integrated electro-optical modulators are used for pulse selection, then compact design is achieved, but the modulation frequency is not high enough to separate individual pulses
Solution Approach 1:
The patent segments the modulation function into two compact integrated modulators rather than using a single large modulator. This segmentation enables each modulator to operate at higher frequencies for pulse separation while maintaining the compact integrated design advantage
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 enhances pulse selection capabilities, allowing for the generation of high selective intensity with improved edge steepness, enabling the handling of high frequencies and efficient energy concentration, while reducing parasitic capacitance effects and heat dissipation.
Implementation Method 1
The transparency of the crystal thus depends on the applied field strength. Electro-optic crystals thus change their optical thickness instantaneously as a function of the strength of an applied external electric field.
Data Source
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AI summary
The device has an optical waveguide (105) for guiding an optical radiation along an axis (104), and two electro-optical modulators (101, 102) for modulating optical transparency of the waveguide. The modulators are arranged one after other along the axis of the waveguide. Control circuits (300, 301) i.e. driver circuits, drive the modulators in a temporal delayed manner, and a carrier substrate is made of a semiconductive material. The waveguide and the control circuits are arranged on the substrate. The modulators are arranged between a light input facet (100) and a light output facet (103). An independent claim is also included for a method for selecting optical pulses with improved edge steepness.