Ultra Compact Optical Transmitter Using Serial Ring Resonators

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Solution Overview

Problem

Current optical transmitters, particularly those using phase shift keying devices, are too large and costly for integration into multi-wavelength systems, requiring a compact, cost-effective, and low-power solution to meet the demands of high-capacity data transmission in metro and inter-datacenter networks.

Innovation Solution

The development of ultra compact optical transmitters utilizing phase shift keying devices with modulated ring resonators and static phase shifters, allowing for serial connection and multiplexing of phase-shifted signals across multiple wavelengths, enabling efficient modulation and transmission of optical signals with reduced size and power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If traditional PDM-QPSK devices are used, then modulation functionality is achieved, but device size is too large for integration

Engineering Contradiction:
Improvetransmitter sizeVSAvoidintegration capability
Core Design Contradiction:
Volume of moving objectVSAdaptability or versatility

Solution Approach 1:

The transmitter is divided into independent functional modules: laser sources for each wavelength, separate phase shift keying devices for each wavelength, and a combiner. This segmentation allows each module to be optimized independently and facilitates integration while maintaining modulation functionality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The phase shift keying devices are designed to handle multiple wavelengths simultaneously through serial connection, creating a universal modulation component that can process different wavelength channels without requiring separate dedicated devices for each wavelength.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Volume of moving object

If device size is reduced for compactness, then integration becomes feasible, but manufacturing precision requirements increase

Engineering Contradiction:
Improvetransmitter sizeVSAvoidalignment precision
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

By segmenting the transmitter into separate functional modules with standardized interfaces, the design allows for modular manufacturing where each module can be precisely fabricated independently and then assembled, distributing the precision requirements across multiple manageable components rather than requiring ultra-precise monolithic fabrication.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Optical coupling elements and alignment structures serve as intermediaries between the segmented modules, providing tolerance compensation and facilitating precise alignment during assembly without requiring extreme manufacturing precision for each individual component.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If multi-wavelength capability is added, then transmission capacity increases, but device complexity increases

Engineering Contradiction:
Improvedata transmission capacityVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The multi-wavelength capability is achieved by adding separate laser sources and phase shift keying devices for each wavelength channel, with each wavelength path being independently controlled. This segmentation allows capacity scaling by simply adding more identical modules rather than redesigning the entire system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The phase shift keying devices are designed with universal functionality to handle multiple wavelengths through serial connection, allowing a single device structure to perform modulation across different wavelength channels, thereby increasing capacity without proportionally increasing device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Use of energy by moving object

If power consumption is reduced, then energy efficiency improves, but transmission distance may be limited

Engineering Contradiction:
Improvepower consumptionVSAvoidsignal transmission capability
Core Design Contradiction:
Use of energy by moving objectVSSpeed

Solution Approach 1:

The design extracts and eliminates high-power components by using direct digital modulation of laser sources and efficient phase shift keying devices, removing the need for high-power amplifiers and complex modulation schemes that consume excessive energy, thereby reducing overall power consumption while maintaining transmission capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system optimizes transmission parameters by selecting appropriate laser wavelengths and modulation depths that maximize energy efficiency, adjusting operational parameters to achieve the desired transmission distance and capacity while minimizing power consumption through optimized device operating points.

Inventive Principle:
Principle #35Parameter changes

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 solution results in significantly smaller, more cost-effective, and power-efficient optical transmitters capable of supporting high-speed data transmission with increased capacity, achieving a 20-fold reduction in size compared to traditional PDM-QPSK devices and a 4-fold reduction compared to EAM-switched PDM phase shift keying transmitters.

Implementation Method 1

each modulated ring resonator being configured to receive an associated modulated electrical signal carrying information and to transfer the information into an associated modulated signal obtained by filtering at the predetermined wavelength λi the non-modulated carrier optical signal depending on the modulated electrical signal

Methodology Applied
Scientific EffectRing resonator filtering: Resonance

Implementation Method 2

the kth static phase shifter is configured to receive and phase shift the kth modulated signal of a phase φk

Methodology Applied
Scientific EffectPhase shifting: Phase Modulation

Implementation Method 3

the multiplexer is configured to receive and multiplex all the phase-shifted signals obtained after the phase shift and to send the phase modulated signal obtained into the output

Methodology Applied
Scientific EffectOptical multiplexing: Interference

Data Source

PatentEP3547571B1Ultra compact optical transmitter
Publication Date: 2021.02.17 NOKIA SOLUTIONS & NETWORKS OY
  • EP3547571B1 patent drawingFigure 1a~1b
  • EP3547571B1 patent drawingFigure 2a~2b
  • EP3547571B1 patent drawingFigure 2c

AI summary

A phase shift keying device (xPSK) configured to modulate in phase a non-modulated carrier optical signal (NMC) at a predetermined wavelength λi, comprising: • a main input (300) configured to receive the non-modulated carrier optical signal (NMC); • an output (301), a throughput (302); • x identical modulated ring resonators (MRR), x being an integer greater than or equal to 2, each modulated ring resonator (MRRx) comprising an input port, an output port and a throughput port, • x static phase shifters (SPS); and • a multiplexer (MUX). Each modulated ring resonator (MRR) is configured to filter at the predetermined wavelength λi the non-modulated carrier optical signal (NMC) depending on a modulated electrical signal (MES). The modulated ring resonators are serially connected and the static phase shifters are configured to receive and phase shift the modulated signals (MS). Finally, the multiplexer (MUX) is configured to multiplex all the phase-shifted signals together.