Optical Transmission Module With Segmented Active Layer Stripe Width
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Solution Overview
Problem
Multi-level pulse amplitude modulation (PAM) systems with more than 2 levels are more susceptible to noise due to smaller differences in signal intensities, which affects data transmission quality.
Innovation Solution
An optical transmission module with a semiconductor active layer having varying stripe widths and a diffraction grating, where the second portion with a narrower stripe width is designed to reduce noise by lowering carrier density and optical confinement rate, and includes separate electrodes and films for modulation and reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multi-level PAM with larger number of levels than 2 is used to achieve larger data traffic volume, then data traffic volume is improved, but noise susceptibility increases due to smaller difference between signal intensities
Solution Approach 1:
The active layer is divided into a first portion with a first stripe width and a second portion with a second stripe width that is smaller than the first stripe width. This segmentation allows different regions to have different optical confinement rates, with the second portion having a lower optical confinement rate to reduce spontaneous emission and noise, thereby improving signal quality for multi-level PAM transmission while maintaining high data traffic volume capability
Solution Approach 2:
Different portions of the active layer are given different local properties: the first portion has a larger stripe width for higher optical confinement and stronger light emission, while the second portion has a smaller stripe width for lower optical confinement and reduced spontaneous emission. This local quality differentiation enables the system to achieve both high data traffic volume and low noise susceptibility simultaneously
2Reliability
If the stripe width of the active layer is reduced to lower carrier density and optical confinement rate, then noise is reduced, but light emission intensity decreases
Solution Approach 1:
The active layer is segmented into two portions with different stripe widths. The first portion maintains a larger stripe width to ensure sufficient light emission intensity, while the second portion uses a smaller stripe width to reduce carrier density and optical confinement rate, thereby reducing spontaneous emission and noise. This segmentation resolves the contradiction by distributing different functions to different regions
Solution Approach 2:
The invention applies local quality by creating regions with different stripe widths within the same active layer. The first portion has high optical confinement for strong light emission, while the second portion has low optical confinement for noise reduction. This local differentiation allows the system to achieve both high light emission intensity and low noise simultaneously
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 module effectively reduces noise in PAM signals by minimizing spontaneous emission and relative intensity noise (RIN), enhancing data transmission reliability.
Implementation Method 1
a second semiconductor layer, which includes a diffraction grating arranged along an extending direction of the active layer
Implementation Method 2
a connection portion, which has a varying stripe width so as to connect the first portion and the second portion to each other
Data Source
AI summary
Provided is an optical transmission module in which noise is further reduced. The optical transmission module includes a first semiconductor layer having a first electrode arranged thereon, an active layer with a stripe shape formed on the first semiconductor layer, and a second semiconductor layer with a stripe shape formed on the active layer. The second semiconductor layer has a second electrode arranged thereon and includes a diffraction grating arranged along an extending direction of the active layer. The active layer includes a first portion having first stripe width, a second portion having a second stripe width smaller than the first stripe width, and a connection portion having a varying stripe width so as to connect the first portion and the second portion to each other. The diffraction grating overlaps with the first portion and does not overlap with the second portion in planar view.