Segmented DFB Laser Array for High-Bandwidth Direct Modulation
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Solution Overview
Problem
Directly modulated lasers (DMLs) are limited by their 3 dB bandwidth due to carrier-photon resonance, restricting achievable data rates to ≤42 Gbps, leading to bandwidth limitations, distortions, and increased bit error rates.
Innovation Solution
A multiple electrode distributed feedback laser array with independently tunable laser segments, featuring a DC and AC electrode configuration, allows for higher data rates by applying a DC bias to a first laser segment for stimulated emission and an AC signal to a second segment for carrier modulation, overcoming bandwidth limitations without increasing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single contact is used to modulate current in a directly modulated laser, then the device is compact and consumes low power, but the 3 dB bandwidth is limited by carrier-photon resonance frequency
Solution Approach 1:
The laser device is divided into multiple laser segments with separate DC and AC electrodes. The DC electrode provides bias current while the AC electrode applies modulation signals independently, allowing the device to overcome the bandwidth limitations of single-contact configuration without increasing overall device complexity
Solution Approach 2:
The invention transitions from a single-dimensional current modulation approach to a multi-dimensional electrode configuration. By adding spatial separation of DC and AC electrodes along the laser cavity, the system achieves independent control of bias and modulation functions, enabling bandwidth extension beyond the traditional carrier-photon resonance limit
2Use of energy by moving object
If direct modulation of DFB is used, then power consumption is low, but achievable data rate is limited to ≤42 Gbps
Solution Approach 1:
The laser is segmented into multiple sections with independent DC and AC electrodes. This segmentation allows the AC modulation electrode to operate independently from the DC bias electrode, enabling high-speed modulation without requiring increased power consumption from the bias circuit
Solution Approach 2:
The invention changes the electrical configuration parameters by introducing separate DC and AC electrodes with independent biasing. This parameter change enables the AC electrode to apply high-frequency modulation signals while the DC electrode maintains optimal bias conditions, achieving data rates above 42 Gbps without increasing overall power consumption
3Volume of moving object
If a single contact configuration is used, then the device is compact, but signal distortion increases and bit error rate increases
Solution Approach 1:
The laser cavity is segmented into multiple sections with independent DC and AC electrodes. This segmentation allows independent optimization of bias conditions and modulation signals, reducing signal distortion and bit error rates while maintaining the compact form factor through integrated electrode design
Solution Approach 2:
The separate AC electrode acts as an intermediary that applies modulation signals without interfering with the DC bias electrode. This intermediary configuration enables clean signal modulation with reduced distortion and lower bit error rates, while the integrated structure maintains device compactness
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 enhances signal integrity and reduces jitter, achieving higher data rates and improved signal quality by optimizing the frequency response and reducing signal distortion.
Implementation Method 1
a primary injection current supporting stimulated emission at a desired optical output power out of the front face of the modulated laser is generated when a DC bias is applied to the DC electrode
Implementation Method 2
a carrier signal of the modulated laser is modulated when an AC signal is applied to the AC electrode
Data Source
AI summary
Apparatuses, methods, and systems for a modulated laser are disclosed. The modulated laser includes a substrate including a plurality of laser segments, a first laser segment comprising a DC electrode, a second laser segment comprising an AC electrode, an isolation barrier formed between the first laser segment and the second laser segment, and a modulated laser cavity spanning from a rear face to a front face of the modulated laser inclusive of the plurality of laser segments, wherein a primary injection current supporting stimulated emission at a desired optical output power out of the front face of the modulated laser is generated when a DC bias is applied to the DC electrode, and wherein a carrier signal of the modulated laser is modulated when an AC signal is applied to the AC electrode, wherein the AC bias is independent of the DC bias.