Mode-Locked Laser Rib With Polynomial Hole Spacing
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Solution Overview
Problem
Current mode-locked lasers integrated on silicon photonic chips do not efficiently emit phase-synchronized multimode laser pulses, which are necessary for high data rates and precision in applications like telecommunications and metrology, due to limitations in energy consumption and resonance mode spacing.
Innovation Solution
A mode-locked laser design featuring a rib structure with a stack of layers and through holes, where the gap spacing between holes varies according to a symmetric polynomial function, forming a resonant cavity that accommodates multiple equidistant resonance modes, and includes absorbent layers for optical pumping and electrical contacts for efficient energy management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform hole spacing is used in the rib structure, then manufacturing is simplified, but phase-synchronized multimode laser pulses cannot be emitted
Solution Approach 1:
The patent applies local quality by varying the spacing between holes at different positions along the rib structure. Specifically, the spacing between adjacent holes changes according to a polynomial function of the hole position, creating non-uniform local regions that enable phase-synchronized multimode pulse emission while maintaining overall structural integrity and manufacturability.
2Productivity
If the cavity length is increased to accommodate more resonance modes, then high data rates are achieved, but the device footprint increases
Solution Approach 1:
The patent changes the geometric parameters of the hole spacing according to a polynomial function, which modifies the resonant frequencies of the cavity. This parameter variation enables the cavity to support multiple equidistant resonance modes within a compact length, achieving high data rates without proportionally increasing the device footprint.
Solution Approach 2:
The non-uniform hole spacing creates a dynamic modulation of the optical path length along the cavity, enabling efficient coupling between multiple longitudinal modes. This dynamic structural variation allows the cavity to accommodate more resonance modes per unit length compared to uniform spacing.
3Device complexity
If uniform hole spacing is used, then the structure is simpler, but resonance modes are not equidistant in frequency
Solution Approach 1:
The patent employs a polynomial function to describe the variation of hole spacing with position, which precisely controls the optical path differences between adjacent holes. This mathematical parameterization ensures that resonance modes are equidistant in frequency while maintaining a systematic and manufacturable structure.
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 design enables the emission of phase-synchronized multimode laser pulses with low energy consumption, supporting high data rates and precision, while being easily integrable on silicon substrates with minimal footprint, suitable for advanced metrology and telecommunications.
Implementation Method 1
each series of holes forms a mirror for the electromagnetic waves
Implementation Method 2
The cavity is adapted to accommodate a plurality of resonance modes equidistant in frequency
Implementation Method 3
the first absorbent layer and the second absorbent layer comprising a saturable absorbent material at at least one resonance frequency of the rib
Implementation Method 4
the waveguide being separated from the rib by a non-zero distance in the direction of stacking
Data Source
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AI summary
Mode-locked laser (10) comprising: - a substrate (12), - a rib (14) that extends over the substrate in a direction of extent (X), forming a resonant cavity, and - a waveguide (16) defined in the substrate. The rib comprises a lower layer (C2), a plurality of intermediate layers (C3 to CN-2) and an upper layer (CN-1). The rib contains a plurality of through-orifices (36) that are aligned in the direction of extent (X). The waveguide is separated from the rib by a nonzero distance. Each orifice is separated from each neighbouring orifice by a spacing, the spacings each having a dimension that varies, in the direction of extent (X), according to a symmetric polynomial law of variation of order higher than or equal to 4.