Parallel Cavity Tunable Laser for Wide Wavelength Range
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Solution Overview
Problem
Current tunable lasers for WDM-PON applications face challenges in covering a wide range of channel wavelengths efficiently, especially at higher data rates, and require a cost-effective solution that can be easily deployed and maintained across various subscriber locations.
Innovation Solution
A parallel cavity tunable laser with multiple thermally tunable cavities sharing a common output, allowing for independent wavelength selection and emission across different wavelength ranges, enabling wider tuning ranges without extending the overall cavity length, and capable of modulating at higher data rates such as 2.5 G or 10 G.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single long cavity is used to cover a wide wavelength range, then the wavelength tuning range is improved, but the modulation capability at higher data rates deteriorates
Solution Approach 1:
The laser device is divided into multiple independent parallel cavities, each capable of operating independently at different wavelengths. This segmentation allows each cavity to maintain optimal modulation performance while the collective system achieves wide wavelength coverage through selective activation of different cavities.
2Adaptability or versatility
If multiple in-line sections are used to cover a wide range of channels, then the wavelength tuning range is improved, but the device complexity increases
Solution Approach 1:
Multiple parallel cavities are merged into a single integrated device structure, sharing common components such as the substrate, contact layers, and packaging. This merging approach achieves wide wavelength coverage while reducing overall device complexity compared to multiple separate laser devices.
3Adaptability or versatility
If temperature control is used to tune DFB lasers across a wide wavelength range, then the wavelength tuning range is improved, but the temperature range required increases
Solution Approach 1:
Instead of relying solely on temperature changes to achieve wavelength tuning, the invention uses structural parameters of multiple parallel cavities (such as cavity length and grating period) to provide different wavelength ranges. This allows wavelength tuning across a wide range while maintaining operation within a limited temperature range.
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 parallel cavity tunable laser provides efficient wavelength tuning over a wide range of channel wavelengths within a smaller temperature range, facilitating the use of a single device across different locations and supporting higher data rates, thus addressing the limitations of existing tunable lasers in WDM-PON systems.
Implementation Method 1
a plurality of parallel laser cavities 310-1 to 310-n each configured to be driven independently to generate laser light at a wavelength within a different respective wavelength range
Implementation Method 2
Each of the plurality of parallel laser cavities 310-1 to 310-n is tunable in response to temperature changes to generate a selected wavelength within the respective wavelength range
Data Source
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AI summary
A parallel cavity tunable laser generally includes a semiconductor laser body defining a plurality of parallel laser cavities with a common output. Each of the parallel laser cavities is configured to be driven independently to generate laser light at a wavelength within a different respective wavelength range. The wavelength of the light generated in each of the laser cavities may be tuned, in response to a temperature change, to a channel wavelength within the respective wavelength range. The laser light generated in each selected one of the laser cavities is emitted from the common output at a front facet of the laser body. By selectively generating light in one or more of the laser cavities, one or more channel wavelengths may be selected for lasing and transmission.