Optical Modulator Array Using Electro-Optic Polymer for MHz Phase Control
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Solution Overview
Problem
Existing light modulators, such as liquid crystal on silicon (LCOS) type SLMs, have limited response speeds of less than 1 kHz due to the speed limitations of liquid crystal layers, while mechanical elements like galvano mirrors offer high speeds but do not modulate light phases accurately.
Innovation Solution
A light modulator with a conductive pattern layer and an electro-optic polymer modulation layer, where the refractive index changes with an applied electric field, allowing for high-speed phase modulation, and a reflection layer to output modulated light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a liquid crystal layer is used for light modulation, then phase modulation capability is achieved, but response speed is limited to less than 1 kHz
Solution Approach 1:
The patent changes the material parameter of the modulation layer from liquid crystal to electro-optic polymer, which fundamentally alters the response characteristics. The electro-optic polymer exhibits significantly faster response speed while maintaining phase modulation capability, directly resolving the contradiction between accuracy and speed.
Solution Approach 2:
The patent replaces the liquid crystal mechanism with an electro-optic polymer mechanism that utilizes the Pockels effect. This substitution eliminates the slow response inherent in liquid crystal reorientation and replaces it with a faster electro-optic response, achieving both high-speed operation and accurate phase modulation.
2Speed
If a mechanical element like galvano mirror is used, then operation speed of 1 kHz or more is achieved, but phase modulation accuracy is insufficient
Solution Approach 1:
The patent replaces mechanical scanning elements with an electro-optic polymer-based phase modulator. This substitution eliminates mechanical inertia and friction, enabling faster response while providing precise phase control through electrical field application, thus achieving both high speed and high accuracy.
Solution Approach 2:
The patent changes from mechanical displacement-based light deflection to electro-optic refractive index modulation. This parameter change enables simultaneous achievement of high operation speed (exceeding 1 kHz) and accurate phase modulation by controlling the electro-optic polymer's refractive index through applied electric fields.
3Speed
If electro-optic polymer is used in the modulation layer, then response speed exceeds 1 MHz, but device complexity increases
Solution Approach 1:
The electro-optic polymer layer serves multiple functions simultaneously: it acts as the modulation medium, the structural layer defining the device geometry, and the element that converts electrical signals to optical modulation. This multi-functionality reduces the need for additional separate components, thereby managing device complexity while achieving high-speed operation.
Solution Approach 2:
The patent employs a composite structure combining electro-optic polymer with transparent electrodes and substrate materials. This composite approach integrates multiple functionalities within a unified structure, enabling high-speed response through the electro-optic polymer while managing overall device complexity through material integration rather than separate components.
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 modulator achieves phase modulation at speeds exceeding 1 MHz by utilizing the faster response of electro-optic polymers, and can function as an optical resonator, enabling accurate wavefront control.
Implementation Method 1
a modulation layer made of an electro-optic polymer, filling a space between the plurality of pattern portions and formed on an upper surface of the conductive pattern layer with a predetermined thickness, and having a refractive index to be changed by applying an electric field using the conductive pattern layer
Data Source
AI summary
A light modulator includes a base layer made of an insulating material having a transmitting property for object light, a conductive pattern layer made of a conductive material, including a plurality of pattern portions arranged periodically, and formed on the base layer, a modulation layer made of an electro-optic polymer, filling a space between the plurality of pattern portions and formed on the conductive pattern layer, and having a refractive index to be changed by applying an electric field, and a reflection layer formed on the modulation layer and reflecting the object light incident from a lower surface of the base layer and transmitted through the modulation layer, and the object light having a phase modulated by being transmitted through the modulation layer and reflected by the reflection layer is output from the lower surface of the base layer to the outside as modulated light.