Integrated Laser Module Layout for Wider Frequency Response
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Solution Overview
Problem
Conventional lasers and laser modules face limitations in response frequency and high manufacturing costs due to complex semiconductor structures and processes, making them unsuitable for next-generation optical network applications.
Innovation Solution
A laser module comprising a substrate with a laser unit and an optical amplification unit, featuring a high reflection layer and a low reflection layer, where the optical channels are connected via a trench forming an inverted trapezoid shape, allowing for improved frequency response and reduced parasitic capacitance, and using a planarized layer of benzocyclobutene to simplify the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional direct modulated laser is used, then the structure is simple, but the response frequency is limited to about 30 GHz
Solution Approach 1:
The patent combines a laser unit and an optical amplification unit into a single integrated module, where the laser unit generates laser light and the optical amplification unit amplifies it. This merging allows the system to achieve higher response frequencies (exceeding 30 GHz) by leveraging the amplification effect while maintaining a relatively compact structure that shares common components like the substrate and optical channels.
Solution Approach 2:
The optical amplification unit serves multiple functions: it amplifies the laser light from the laser unit, provides gain through population inversion, and enables high-frequency modulation capability. The shared substrate and optical channels between the laser unit and optical amplification unit reduce overall device complexity while achieving multi-functionality.
2Speed
If indirect modulated laser is used to change amplitude or phase, then the frequency response can be improved, but the method becomes more complicated and requires repeated epitaxy
Solution Approach 1:
The patent integrates the laser unit and optical amplification unit in a way that allows direct modulation capability while achieving high frequency response. The direct modulation approach modulates the injection current directly, avoiding the complexity of indirect modulation methods while maintaining high-speed performance through the amplification effect.
Solution Approach 2:
The patent uses parameter changes in the epitaxial growth process, specifically growing an InGaAsP material on an InP substrate with controlled composition and thickness to form quantum well structures. This precise parameter control enables high-quality material growth without requiring repeated epitaxy cycles, simplifying the manufacturing process while achieving the desired optical properties.
3Adaptability or versatility
If repeated epitaxy is performed for semiconductor structures, then the laser and optical amplification functions can be achieved, but the process difficulty and cost increase
Solution Approach 1:
The patent achieves both laser and optical amplification functions in a single epitaxial growth process by carefully controlling the composition and thickness parameters of the InGaAsP layers. The quantum well structures are designed with specific thicknesses (e.g., 5-10 nm) and compositions that enable both gain and lasing action without requiring multiple separate epitaxy steps, thereby reducing process complexity and cost.
Solution Approach 2:
The patent uses composite material structures consisting of InGaAsP quantum wells embedded in InP cladding layers. This composite structure provides both the gain medium for optical amplification and the resonant cavity conditions for lasing, achieving multiple functions through a single integrated material system rather than requiring separate structures and processes.
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 effectively widens the bandwidth of frequency response, reduces parasitic capacitance and contact resistance, and simplifies the manufacturing process, enabling high-speed functions while lowering costs.
Implementation Method 1
a laser unit (2), an optical amplification unit (3)... The laser unit (2) is disposed on the substrate and configured to generate a laser light
Implementation Method 2
A gain light is produced by entering the laser light emitted from the optical channel of the laser unit into the optical channel of the optical amplification unit, such that electrons in the optical channel of the optical amplification unit that have energy higher than a ground state are induced to return to the ground state
Implementation Method 3
The high reflection layer (4) is disposed on an end of the laser unit oriented away from the optical amplification unit (3). The low reflection layer (5) is disposed on an end of the optical amplification unit (3) oriented away from the laser unit (2). The reflectance of the low reflection layer (5) is fine tunable.
Implementation Method 4
fine tuning the reflectance of the low reflection layer to cause a reflected light of the optical amplification unit to induce a photon-photon resonance effect with the laser light of the laser unit
Implementation Method 5
forming a trench along an X-axis direction by performing a dry etching process toward a −Z direction to a predetermined depth, and then performing a wet etching method toward +Y and −Y directions to form angled sidewalls, such that a cross-section of the trench is an inverted trapezoid... reduces parasitic capacitance and contact resistance
Data Source
AI summary
A laser module includes a substrate, a laser unit, an optical amplification unit, a high reflection layer and a low reflection layer. The laser unit is disposed on the substrate and configured to generate a laser light. The optical amplification unit is disposed on the substrate. An optical channel of the optical amplification unit is communicated with an optical channel of the laser unit. An electrode of the optical amplification unit is electrically isolated from an electrode of the laser unit. The high reflection layer is disposed on an end of the laser unit away from the optical amplification unit. The low reflection layer is disposed on an end of the optical amplification unit away from the laser unit. The laser light and a gain light are emitted to an outside of the laser module via the low reflection layer. A method for manufacturing the laser module is also provided.