Optical Reflective Multiplexer Chip for Cost-Effective WDM Transmitters

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Solution Overview

Problem

Current colorless optical transmitters based on self-injection locking technology have high costs due to the use of high-cost discrete components like Faraday rotators and AWG components.

Innovation Solution

The implementation of an optical reflective multiplexer chip and a laser transmitter chip that utilize microring resonant cavities, polarization splitter-rotators, and a combiner to perform wavelength selection and polarized light coupling, eliminating the need for expensive discrete components by integrating the functionality within the chip.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If discrete components (Faraday rotator and AWG component) are used to implement self-injection locking technology, then wavelength selection and self-injection locking functions are achieved, but the cost of the optical transmitter becomes excessively high

Engineering Contradiction:
Improvewavelength selection capabilityVSAvoidcost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent integrates multiple discrete components (Faraday rotator, AWG component, and other optical elements) into a single integrated optical reflective multiplexer chip. This merging eliminates the need for separate discrete components and their associated connections, thereby reducing cost while maintaining the wavelength selection and self-injection locking functions.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated optical reflective multiplexer chip performs multiple functions simultaneously: wavelength selection, polarization control, and self-injection locking. By combining these functions into a single chip, the patent reduces the overall system cost while maintaining all necessary capabilities for colorless WDM optical transmission.

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

2Adaptability or versatility

If multiple optical modules of different wavelengths are allocated to RRUs, then wavelength-specific transmission is achieved, but the system complexity and inventory requirements increase

Engineering Contradiction:
Improvewavelength allocation flexibilityVSAvoidsystem configuration complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The integrated chip enables a single optical module to adapt to different wavelengths through self-injection locking, making the system universal rather than wavelength-specific. This eliminates the need for multiple wavelength-specific modules and simplifies the overall system configuration.

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

Solution Approach 2:

The optical module automatically selects the appropriate wavelength through self-injection locking mechanism, without requiring manual configuration or external control. This self-service capability reduces system complexity and enables plug-and-play functionality across different ports.

Inventive Principle:
Principle #25Self-service

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 reduces the overall cost of the optical transmitter while maintaining effective wavelength selection and self-injection locking, enabling efficient and cost-effective data transmission.

Implementation Method 1

N microring resonant cavities... each of the N microring resonant cavities is configured to: perform wavelength selection on the light transmitted to the corresponding first branch waveguide and the corresponding second branch waveguide

Methodology Applied
Scientific EffectMicroring resonant cavity wavelength selection: Resonance

Implementation Method 2

N polarization splitter-rotators... each of the N polarization splitter-rotators is configured to: receive polarized light, and transmit the polarized light to the corresponding first and second branch waveguides after the polarized light passes through the polarization splitter-rotator

Methodology Applied
Scientific EffectPolarization splitting: Polarisation

Implementation Method 3

the polarization splitter-rotator is configured to: perform polarized coupling on the reflective polarized light transmitted back by the corresponding microring resonant cavity, and output the coupled light from the corresponding third external port

Methodology Applied
Scientific EffectPolarization rotation: Polarisation

Implementation Method 4

A self-injection locking technology is a solution that is proposed recently to implement a colorless WDM optical transmitter. For example, multi-longitudinal mode (wavelength) light emitted by a Fabry Perot-Laser Diode (English full name: Fabry Perot-Laser Diode, FP-LD for short) is reflected and is re-injected into the FP-LD, to lock a particular wavelength.

Methodology Applied
Scientific EffectSelf-injection locking: Feedback

Data Source

PatentEP3402094B1Optical reflective multiplexer chip, laser transmitter chip and optical transmitter
Publication Date: 2021.04.28 HUAWEI TECH CO LTD
  • EP3402094B1 patent drawingFigure 1~2
  • EP3402094B1 patent drawingFigure 3~4
  • EP3402094B1 patent drawingFigure 5

AI summary

An optical reflective multiplexer chip (42), a laser transmitter chip (40), and an optical transmitter (4) are disclosed, to resolve a problem that currently a colorless optical transmitter (4) based on a self-injection locking technology has high costs. The optical transmitter (4) includes: the laser transmitter chip (40), an optical fiber (41), and the optical reflective multiplexer chip (42). The laser transmitter chip (40) includes a bi-directional light emitting laser (400), a polarization splitter-rotator (401), and a first external port (402). The optical reflective multiplexer chip (42) includes a combiner (420), a second external port (421), N third external ports (422), N microring resonant cavities (423), N polarization splitter-rotators (424), N first branch waveguides (425), and N second branch waveguides (426), where N is a positive integer and is greater than or equal to 1. The combiner (420) is connected to the first branch waveguide (425), the second branch waveguide (426), and the second external port (421). The first external port (402) is connected to the third external port (422) by using the optical fiber (41).