Superluminescent Diode HOCF LOCF Regions Broad Bandwidth
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Solution Overview
Problem
Existing superluminescent diodes face limitations in achieving high optical power while maintaining a broad wavelength bandwidth, as methods to increase bandwidth often result in insufficient optical power, such as the low optical power of approximately 1.5 mW reported in previous studies.
Innovation Solution
The design incorporates high optical confinement factor (HOCF) and low optical confinement factor (LOCF) regions within the quantum well structure, with varying thickness and composition of quantum well and barrier layers, and a transition region to reduce optical reflection, allowing for high optical power and broad wavelength bandwidth without saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If methods to increase wavelength bandwidth are used (such as attaching active layers with different wavelengths or quantum well intermixing), then the wavelength bandwidth is broadened, but the optical power becomes insufficient
Solution Approach 1:
The active layer is segmented into multiple quantum well layers with different bandgap energies, each emitting at different wavelengths. This segmentation allows the device to cover a broad wavelength spectrum while maintaining high optical power through stimulated emission in each segment
Solution Approach 2:
The patent uses composite quantum well structures with different material compositions (InGaAsP layers with varying indium and aluminum content) to create regions with different emission wavelengths. This composite approach enables simultaneous high power output across a broad wavelength bandwidth by combining multiple emission bands in a single device structure
2Adaptability or versatility
If the SLD is configured to reduce optical resonance phenomena to achieve wide optical bandwidth, then the optical bandwidth increases, but it becomes difficult to provide required high optical power
Solution Approach 1:
Different regions of the active layer are designed with different optical confinement factors. The first through fourth quantum well layers have different confinement characteristics, allowing local optimization where some regions provide high power through strong confinement while others broaden bandwidth through reduced resonance
Solution Approach 2:
The patent systematically varies key parameters including quantum well thickness, barrier layer thickness, and material composition across different quantum well layers. These parameter changes create a gradient in optical confinement factors, enabling the device to achieve both high optical power and broad bandwidth by optimizing the balance between confinement and resonance suppression
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 approach enables the superluminescent diode to produce high optical power and broad wavelength bandwidth by preventing saturation in the active layers, allowing for adjustable output and wavelength bandwidth through the length control of HOCF and LOCF regions, thereby overcoming the limitations of previous designs.
Implementation Method 1
Like a laser diode, the SLD uses optical amplification phenomena by stimulated emission to achieve high optical power
Implementation Method 2
at least one high optical confinement factor (HOCF) region; and at least one low optical confinement factor (LOCF) region having a lower optical confinement factor than the HOCF region
Data Source
AI summary
Provided are a superluminescent diode with a high optical power and a broad wavelength band, and a method of fabricating the same. The superluminescent diode includes: at least one high optical confinement factor (HOCF) region; and at least one low optical confinement factor (LOCF) region having a lower optical confinement factor than the HOCF region. The method includes obtaining a difference of optical confinement factors in the HOCF region and the LOCF region through a selective area growth method, the selective area growth method using a deposition thicknesses difference of thin layers according to a width difference of openings that expose a substrate.