DWDM Laser Chip Packaging for Precise Wavelength Alignment
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Solution Overview
Problem
Existing DWDM optical devices face challenges in precisely adjusting wavelengths for narrow guardbands and temperature stability, particularly in burst mode operations, leading to inefficient communication capacity and increased complexity and cost.
Innovation Solution
An optical device with two laser diode chips on a thermoelectric element, equipped with a heater, allows independent temperature control and wavelength adjustment using a polarization combiner and heater to maintain precise wavelength alignment and suppress wavelength shifts during burst mode operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a 45-degree dichroic filter is used to combine multiple wavelengths into one optical path, then wavelength combining capability is improved, but wavelength adjustment precision deteriorates when guardband is narrow (within 0.6 nm)
Solution Approach 1:
The patent divides the wavelength combining function into two stages: first, a 45-degree dichroic filter performs coarse wavelength separation for channels with guardband ≥0.6 nm; second, a polarization beam combiner performs fine wavelength combining for channels with guardband <0.6 nm. This segmentation allows each component to optimize for its specific function, resolving the precision limitation of the 45-degree filter.
Solution Approach 2:
The patent introduces a polarization beam combiner as an intermediary component between the laser diodes and the 45-degree dichroic filter. This intermediary enables precise wavelength control for narrow guardband channels by utilizing polarization state manipulation, which is not affected by incident angle variations that plague the 45-degree filter approach.
2Measurement precision
If the incident angle of light on the dichroic filter is adjusted to achieve precise wavelength control, then wavelength precision is improved, but device complexity and adjustment difficulty increase
Solution Approach 1:
The patent replaces the mechanical incident angle adjustment system with an optical polarization control system. Instead of mechanically adjusting the incident angle of light on the dichroic filter, the system uses polarization beam combiners that control wavelength through polarization states, eliminating complex mechanical adjustment mechanisms while achieving precise wavelength control.
3Productivity
If two or more laser diode chips are bundled into one optical device package to increase transmission speed, then productivity is improved, but temperature control precision deteriorates
Solution Approach 1:
The patent segments the temperature control system by providing individual thermoelectric elements for each laser diode chip. This allows independent temperature control of each chip, ensuring that each laser operates at its optimal temperature despite being packaged together with other lasers. The segmentation prevents thermal interference between adjacent lasers while maintaining high transmission speed through parallel operation.
4Measurement precision
If multiple thermoelectric elements are used for independent temperature control of each laser diode chip, then temperature control precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies local quality by providing individual thermoelectric elements only for laser diode chips that require independent temperature control, rather than uniformly equipping all chips. This allows precise temperature control for specific lasers with narrow guardband requirements while avoiding unnecessary complexity for lasers with wider guardbands, optimizing the balance between precision and simplicity.
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 enables precise wavelength control and stable transmission speed, doubling the communication capacity while reducing the number of thermoelectric elements and maintaining economic efficiency.
Implementation Method 1
a thermoelectric element; a heater mounted on at least one laser diode chip among the laser diode chips, wherein the at least two laser diode chips are configured to independently emit laser lights at center wavelengths of different communication channels by applying a temperature acquired by operating the heater in addition to a temperature generated by the thermoelectric element
Implementation Method 2
a heater mounted on at least one laser diode chip among the laser diode chips, wherein the at least two laser diode chips are configured to independently emit laser lights at center wavelengths of different communication channels by applying a temperature acquired by operating the heater
Implementation Method 3
two or more optical devices capable of changing their wavelengths are disposed in one optical device package
Data Source
AI summary
Provided is a dense wavelength division multiplexing (DWDM) optical device having two light source chips, in which two or more semiconductor laser diode chips, respectively corresponding to a plurality of wavelength channels, are combined into one optical device package, and the respective semiconductor lasers are simultaneously driven to have a transmission speed twice faster than a case of driving one semiconductor laser.