Electro-Optical Modulator Using Photocathode for THz Signal Control
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Solution Overview
Problem
Conventional electro-optical modulators require high operating voltages and have slow response times, limiting their ability to operate at high frequencies and facilitate fast signal modulation and attenuation.
Innovation Solution
A novel electro-optical modulator device that uses a light modulator unit with a Cathode and an electric field source to change the refractive index, allowing for fast signal modulation and attenuation by varying the electric field, enabling operation up to the THz range and supporting high-frequency interconnects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional electro-optical modulators are used, then signal modulation capability is provided, but high operating voltages are required and response time is slow
Solution Approach 1:
The patent changes the fundamental operating parameters by using a photocathode structure where the refractive index is modulated through photoelectric effect rather than conventional high-voltage electro-optic effect. This enables operation at much lower voltages while achieving faster response times in the THz range.
Solution Approach 2:
The patent replaces the conventional electro-optic mechanism with a photoelectric mechanism. Instead of using high voltage electric fields to change refractive index, the invention uses light-induced electron emission from photocathode to achieve refractive index modulation, enabling faster and more energy-efficient operation.
2Productivity
If conventional electro-optical modulators are used, then modulation function is achieved, but operation frequency is limited
Solution Approach 1:
The patent utilizes the photoelectric effect as a phase transition mechanism where incident light causes abrupt electron emission from the photocathode surface. This quantum mechanical phase transition enables extremely fast response times and operation frequencies in the THz range, far exceeding conventional modulators.
3Ease of operation
If high operating voltages are applied to change refractive index, then light propagation control is achieved, but device complexity and power consumption increase
Solution Approach 1:
The patent introduces light as an intermediary to control the refractive index. Instead of directly applying high voltage to the modulator material, the invention uses incident light on the photocathode to generate electron emission, which indirectly controls the refractive index. This intermediary approach simplifies the control system and reduces power consumption.
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 device achieves very fast signal switching and high-frequency operation, overcoming the limitations of conventional modulators by reducing capacitance and enabling efficient signal modulation and attenuation, suitable for optical communications and replacing traditional metal interconnects.
Implementation Method 1
an electric field source configured and operable to create a potential difference between two opposite surfaces of the first Cathode to thereby enabling to cause a change in the refractive index of the first Cathode by varying the electric field
Implementation Method 2
The first Cathode may be configured as a Photocathode. In this case, the electric current through the light modulator unit is a current of electrons which are ejected from the first Photocathode
Implementation Method 3
The light output of the light modulator unit when reaching the second Photocathode causes electrons' extraction from the second Photocathode to thereby affect an electric current between the second Photocathode and its associated (second) Anode
Data Source
AI summary
An electro-optical modulator device and method are provided. The device comprises a light modulator unit having a first Cathode for exposing to input light; and an electric field source configured to create an electric field affecting a change in the refractive index of the first Cathode, thereby effecting a change in the propagation of light reflected from or transmitted through the first Cathode, said light from the first Cathode enabling to affect the operation of an external light sensitive electronic device.