MEMS Optical Switches for Thermal Crosstalk in Phased Array Chips

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Solution Overview

Problem

Conventional two-dimensional optical phased arrays face limitations due to optical crosstalk and thermal isolation issues with electro-optic or thermo-optic switches, restricting the range of longitudinal directionality control.

Innovation Solution

The use of micro electro mechanical system (MEMS) optical switches and thermal-isolated phase controller arrays on a single integrated circuit, with a resistor buried phase control structure to minimize thermal interference and suppress unnecessary heat conduction, allowing for expanded longitudinal emission angles without optical crosstalk.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electro-optic or thermo-optic optical switches are used in conventional two-dimensional optical phased arrays, then the switching function can be achieved, but optical crosstalk occurs and thermal isolation between channels is limited

Engineering Contradiction:

Improveswitching functionVSAvoidoptical crosstalk and thermal interference

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the conventional electro-optic or thermo-optic switching mechanisms with a MEMS (micro-electro-mechanical system) switch. This mechanical-based switching approach physically blocks or directs optical paths through micromirrors or microactuators, thereby eliminating optical crosstalk and reducing thermal interference between adjacent channels while maintaining reliable switching functionality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If a two-dimensional optical phased array structure is implemented to expand longitudinal directionality range, then the emission angle range increases, but the device complexity increases due to additional optical switches

Engineering Contradiction:

Improvelongitudinal directionality rangeVSAvoidnumber of optical switches

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent integrates multiple functional components including the MEMS switch, phase controller arrays, and optical phased arrays onto a single integrated circuit substrate. This merging of functions reduces the overall device complexity by eliminating the need for separate optical switches and reducing interconnections, while still achieving the expanded longitudinal directionality range through the coordinated operation of the integrated components.

Inventive Principle:

Principle #5Merging (Combining)

3Ease of manufacture

If release process is applied to all components during manufacturing, then certain structural requirements are met, but unnecessary performance degradation occurs in components that do not require release formation

Engineering Contradiction:

Improverelease process applicationVSAvoidcomponent performance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent implements a selective release process where the release mechanism is applied only to specific components that require it (such as certain waveguide structures or isolator regions) while excluding components that do not require release formation (such as the light splitter and optical antenna arrays). This localized application of the release process prevents unnecessary performance degradation in components where release would be harmful, while still achieving the necessary manufacturing objectives for components that require it.

Inventive Principle:

Principle #3Local quality

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 solution enhances the longitudinal steering range of optical beams by overcoming the limitations of conventional two-dimensional optical phased arrays, improving phase control efficiency and reducing thermal interference.

Implementation Method 1

Each of the plurality of optical switches may include a MEMS actuator, a coupling waveguide driven by the MEMS actuator

Methodology Applied

Scientific EffectMEMS (Micro Electro Mechanical System): Microelectromechanical Systems

Implementation Method 2

The coupling waveguide may transmit an optical wave propagating to the bus waveguide through a first optical coupling to the coupling waveguide

Methodology Applied

Scientific EffectOptical coupling:

Implementation Method 3

an optical phased array chip according to embodiments has a resistor buried phase control structure in which thermal isolation of the release regions formed in the plurality of phase controller arrays is implemented in order to minimize thermal interference and suppress unnecessary thermal conduction

Methodology Applied

Scientific EffectThermal isolation: Thermal Insulation

Data Source

PatentUS11640030B2Optical phased array chip using MEMS switch and manufacturing method thereof

Publication Date: 2023.05.02 KOREA ADVANCED INST OF SCI & TECH

AI summary

Disclosed are an optical phased array chip and a method of manufacturing the same. The optical phased array chip includes a plurality of optical switches and a plurality of optical phased arrays implemented on a single integrated circuit, wherein the single integrated circuit includes a silicon substrate, a lower layer formed on an upper portion of the silicon substrate, a silicon layer formed on an upper portion of the lower layer, a first upper layer, a second upper layer and a third upper layer sequentially arranged on the silicon layer, and an electrode that penetrates through the first upper layer while being grounded to the silicon layer and is formed on an upper portion of the first upper layer.