Compact Photonic Spectrometers Using Tunable Ring Resonators

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Solution Overview

Problem

Conventional spectrometers face challenges in miniaturization and compact integration due to their large hardware footprint, making it difficult to analyze spectral composition of light signals effectively.

Innovation Solution

The development of compact spectrometers using Mach-Zehnder interferometers with tunable refractive indices, distributed Bragg reflectors, and tunable ring resonators, which allow for the determination of spectral content through variable refractive index tuning and partitioning of light signals, enabling device miniaturization and improved spectral resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If conventional spectrometer designs are used, then spectral analysis capability is achieved, but device footprint and size become large

Engineering Contradiction:

Improvedevice footprintVSAvoidspectral resolution

Core Design Contradiction:

Volume of moving objectVSMeasurement precision

Solution Approach 1:

The spectrometer is segmented into multiple functional integrated circuits: first optical path IC, second optical path IC, and detection IC. Each IC performs specific functions (light splitting, spectral dispersion, detection) allowing the system to achieve full spectral analysis capability while minimizing individual component sizes and enabling compact integration.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent transitions from conventional bulk optical components to planar integrated circuit implementations, effectively moving the system into a two-dimensional integration regime. This allows spectral analysis functions to be packed into a much smaller footprint while maintaining performance through precise photolithographic fabrication of waveguides and optical elements.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Volume of moving object

If device miniaturization is achieved, then compact integration is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvedevice sizeVSAvoidintegration difficulty

Core Design Contradiction:

Volume of moving objectVSEase of manufacture

Solution Approach 1:

Each integrated circuit is designed as a universal platform that can handle multiple wavelengths and spectral ranges. The first optical path IC and second optical path IC use identical structural designs but针对不同 spectral regions, allowing standardized manufacturing processes to be applied across different spectrometer configurations while maintaining miniaturization benefits.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent replaces mechanical optical alignment and adjustment mechanisms with fixed, precisely fabricated waveguide structures and optical couplings integrated directly into the IC substrates. This eliminates the need for complex mechanical assemblies and manual alignment procedures, simplifying manufacturing while enabling compact integration.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If spectral resolution is enhanced, then measurement precision is improved, but device complexity increases

Engineering Contradiction:

Improvespectral resolutionVSAvoidoptical path complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The detection function is extracted and isolated onto a separate detection IC, while the optical processing functions are contained in dedicated optical path ICs. This extraction allows each component to be optimized for its specific function, achieving high spectral resolution through precise optical design without requiring the entire system to be complex.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent implements a nested architecture where the first optical path IC processes one spectral range and feeds into the second optical path IC for further processing, with both ultimately feeding the detection IC. This nested arrangement allows complex spectral analysis to be achieved through a hierarchy of simpler, specialized stages, managing overall device complexity.

Inventive Principle:

Principle #7Nested doll (Nesting)

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

These compact spectrometers achieve device miniaturization, reduced power consumption, and enhanced spectral resolution, overcoming the limitations of conventional designs by focusing power on a single detector and improving signal-to-noise ratio.

Implementation Method 1

The input signal is partitioned using Bragg reflectors, which have bandwidth equal to the free spectral range of the resonator

Methodology Applied

Scientific EffectBragg reflection: Bragg Diffraction

Implementation Method 2

by tuning the ring resonators the spectral content of the input signal can be determined

Methodology Applied

Scientific EffectRefractive index tuning:

Implementation Method 3

tunable index ring resonator

Methodology Applied

Scientific EffectResonance: Resonance

Implementation Method 4

A spectrometer typically refers to an apparatus that is used to measure spectrum

Methodology Applied

Scientific EffectInterference: Interference

Implementation Method 5

the refractive index in one of the device arms is tunable

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS11118975B2Miniaturized and integrated photonic spectrometers

Publication Date: 2021.09.14 RGT UNIV OF CALIFORNIA

AI summary

Compact optical spectrometers are provided to measure optical spectral composition of light.