Dual-Emission U-Laser Layout for Balanced Mach-Zehnder Modulation
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Solution Overview
Problem
Prior tunable lasers with a single primary mirror output face challenges in characterization, testing, and calibration, leading to design and reliability tradeoffs, particularly when integrated with optical data modulators, due to difficulties in measuring mirror and laser output characteristics and non-balanced power splitting.
Innovation Solution
A monolithically integrated dual optical emission port laser with balanced power outputs, where both optical emission ports are connected directly to the Mach-Zehnder modulator, eliminating the need for power splitters and allowing equal power extraction from each facet, enabling improved performance and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a single primary mirror output is used in prior tunable lasers, then maximum power can be extracted from one mirror, but this leads to non-balanced power splitting and difficulties in characterization and testing
Solution Approach 1:
The laser system is segmented into two separate optical emission ports (first and second ports) instead of using a single primary mirror output. Each port is connected to a separate arm of the Mach-Zehnder modulator, enabling balanced power splitting and simplified characterization by allowing independent measurement of each port's output characteristics
Solution Approach 2:
A second optical emission port is created as a copy of the first port, both connected to the modulator inputs. This duplication allows for balanced power distribution and enables characterization techniques where each port can be independently tested and calibrated, resolving the measurement difficulties of single-port systems
2Power
If maximum power is extracted from one mirror, then power into modulator is maximized, but this results in decreased side mode suppression ratio and decreased wavelength tuning selectivity
Solution Approach 1:
The optical output is segmented into two separate ports that feed into separate arms of the Mach-Zehnder modulator. This segmentation allows each port to operate at optimized power levels while the interferometric combination in the modulator achieves the desired side mode suppression ratio and wavelength tuning selectivity, resolving the tradeoff between power extraction and optical quality
Solution Approach 2:
The outputs from both optical emission ports are merged through the Mach-Zehnder modulator's interferometric combination. This merging process combines the optical fields in a way that achieves high side mode suppression ratio and wavelength tuning selectivity while maintaining high input power to the modulator, eliminating the need to sacrifice optical quality for power extraction
3Device complexity
If a single primary output mirror is used, then device complexity is reduced, but this leads to non-balanced power splitting and design tradeoffs
Solution Approach 1:
The laser structure is segmented into two symmetric optical emission ports instead of using a single primary output mirror. This segmentation creates a more complex physical structure but eliminates design tradeoffs by enabling balanced power splitting and removing the need for compromise in reliability-critical parameters
Solution Approach 2:
The patent transitions from an asymmetric single-primary-mirror design to a symmetric dual-port design. This symmetry in the optical path lengths and power distribution eliminates the non-balanced power splitting issue, resolving the reliability tradeoffs associated with asymmetric designs
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 configuration simplifies characterization and calibration, reduces design and reliability tradeoffs, and enhances the side mode suppression ratio and wavelength tuning selectivity, resulting in a more efficient and reliable tunable laser system.
Implementation Method 1
an optical data modulator that communicates with both optical emission ports, where the optical data modulator modulates an optical signal from the dual emission port laser by interfering light waves in two arm paths
Data Source
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AI summary
According to the present invention, a monolithically integrated laser (102), also referred to herein as a U-laser (102), or integrated dual optical emission laser (102), having a first optical emission (104) and a second optical emission (106) where both the first and second optical emissions (104), (106) of the monolithically integrated laser (102) are in optical communication with a modulator (108) or other device is provided. The integrated dual emission laser (102) can be formed with a a light bending portion (134) in variety of configurations including a waveguide in the form of a U-shape, or total internal reflection (TIR) mirrors, curved waveguides, and free-space etched gap mirrors. The integrated dual optical emission laser (102) can also have two laser gain sections (130), (148), one on each arm of the laser (102) to control gain.