Monolithic Optical Bench With Doubly-Curved Element

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Solution Overview

Problem

Conventional optical bench systems suffer from weak coupling efficiency, high propagation loss, and limited optical beam travel distance due to their inability to focus or collimate optical beams, and they are not monolithic, making it difficult to integrate MEMS actuators for in-plane or out-of-plane optical component movement.

Innovation Solution

A monolithic optical bench system with a three-dimensional curved optical element etched into the substrate, where the optical axis lies within the substrate and is parallel to the plane, coupled with a MEMS actuator for in-plane movement, enabling 3-D focusing, collimation, and beam transformation of in-plane optical beams.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional flat optical elements are used in optical bench systems, then the system structure is simple and easy to manufacture, but the coupling efficiency is weak and propagation loss is high

Engineering Contradiction:
Improvestructural simplicityVSAvoidpropagation loss
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent applies curved surfaces to optical elements etched in the substrate. Specifically, concave curved surfaces are created to focus and collimate optical beams, replacing conventional flat optical elements. This curvature enables the optical elements to manipulate light more effectively, reducing propagation loss while maintaining manufacturability through standard micromachining processes.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Reliability

If lensed optical fibers are used to achieve beam collimation, then the optical performance improves, but the system cost increases and optical working distance is limited

Engineering Contradiction:
Improveoptical performanceVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the optical element and substrate into a monolithic integrated structure. The optical elements are directly etched into the substrate, eliminating the need for separate lensed optical fibers and their associated alignment mechanisms. This integration maintains high optical performance while reducing system complexity and cost.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent transitions from using external lensed fibers to creating three-dimensional curved optical elements within the substrate plane. By etching concave surfaces that extend into the substrate, the system achieves beam collimation and focusing capabilities without requiring additional optical components outside the substrate.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Ease of manufacture

If cylindrical mirrors with standard fiber cross section are used for beam focusing, then the system is easier to manufacture, but the focusing ability is limited and reflection loss increases

Engineering Contradiction:
Improvemanufacturing easeVSAvoidfocusing ability
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent employs doubly-curved concave surfaces instead of simple cylindrical mirrors. These surfaces have curvature in multiple directions, enabling superior focusing and collimation of optical beams. The enhanced curvature geometry improves focusing ability and reduces reflection loss while remaining compatible with standard micromachining processes.

Inventive Principle:
Principle #14Spheroidality (Curvature)

4Ease of operation

If optical elements are positioned above the substrate surface, then the optical axis is accessible, but monolithic integration of MEMS actuators becomes difficult

Engineering Contradiction:
Improveoptical axis accessibilityVSAvoidintegration complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent repositions the optical axis within the substrate plane rather than above it. Optical elements are etched into the substrate with their optical axes parallel to the substrate surface, enabling MEMS actuators to be integrated beneath the optical path. This dimensional reconfiguration allows monolithic integration while maintaining optical functionality.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 optical performance by allowing for efficient manipulation of in-plane optical beams, improving coupling efficiency and reducing propagation losses, and enables monolithic integration with optical sources, suitable for various applications like interferometers and tunable lasers.

Implementation Method 1

a three-dimensional curved optical element etched in the substrate... enabling 3-D focusing, collimation, and beam transformation of in-plane optical beams

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

a Micro-Electro-Mechanical Systems (MEMS) actuator coupled to the moveable optical element... configured to move in-plane with respect to the substrate

Methodology Applied
Scientific EffectMicro-Electro-Mechanical Systems actuation: Microelectromechanical Systems

Data Source

PatentEP2769257B1Integrated monolithic optical bench containing a doubly-curved optical element and method of its fabrication
Publication Date: 2018.12.12 SI WARE SYSTEMS INC(EG)
  • EP2769257B1 patent drawingFigure 1
  • EP2769257B1 patent drawingFigure 2A~2J
  • EP2769257B1 patent drawingFigure 2K~2M

AI summary

An optical system, such as an integrated monolithic optical bench, includes a three-dimensional curved optical element etched in a substrate such that the optical axis of the optical system lies within the substrate and is parallel to the plane of the substrate.