Bloch Mirror Resonator for Multi-Wavelength DFB Lasers
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Solution Overview
Problem
Current distributed feedback lasers are limited to emitting light at a single wavelength, preventing the design of a cavity that can confine and amplify multiple colors, which is essential for developing white light sources with broader applications in communication, automotive lighting, and horticulture.
Innovation Solution
A Bloch mirror resonator is introduced, replacing conventional Bragg mirrors, allowing for the expansion of operating wavelengths from single to multicolor ranges by using a dielectric slab with aligned periodic boundaries and specific thickness modulation, enabling the amplification of white light components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional Bragg mirror is used in a DFB laser, then the laser can emit light at a specific wavelength, but it is limited to single wavelength operation and cannot confine multiple colors
Solution Approach 1:
The patent applies parameter changes by modifying the Bragg mirror structure into a Bloch mirror with specific geometric parameters. The Bloch mirror uses a periodic structure with period a and thickness d satisfying d=a√3/2, creating aligned periodic boundaries that generate Bloch band gaps. This parameter optimization enables the mirror to confine multiple wavelengths simultaneously while maintaining a single-cavity structure, thus expanding wavelength range without proportionally increasing device complexity
Solution Approach 2:
The patent employs composite materials by combining dielectric materials with specific refractive indices to create the Bloch mirror structure. The periodic arrangement of dielectric layers with different optical properties creates the desired Bloch band gap effect, enabling multi-wavelength confinement through material composition rather than simple geometric modification alone
2Quantity of substance
If a Bragg mirror with period a is used, then light of wavelength λ=2a is blocked, but only a single wavelength can be confined and amplified
Solution Approach 1:
The patent introduces asymmetry in the periodic structure arrangement by aligning the periodic boundaries of the Bloch mirror rather than using the conventional 180-degree phase shift between layers. This asymmetric alignment creates unique Bloch band gap characteristics that broaden the wavelength confinement capability beyond the single wavelength λ=2a limitation of conventional Bragg mirrors
Solution Approach 2:
The patent creates dynamic wavelength confinement by designing the Bloch mirror to support multiple band gaps at different wavelengths simultaneously. The periodic structure with optimized parameters d=a√3/2 creates a dynamic response to different wavelength inputs, enabling the single mirror structure to confine and amplify multiple wavelengths through its frequency-dependent Bloch filtering characteristics
3Adaptability or versatility
If a single frequency laser is used, then the laser structure is simple, but applications requiring white light or broad spectrum are not achievable
Solution Approach 1:
The patent achieves universality by designing the Bloch mirror-based laser cavity to perform multiple functions simultaneously: it can confine and amplify multiple wavelengths (red, green, blue components) within a single cavity structure. This multi-functional capability enables the laser to produce white light output while maintaining the simplicity of a single-cavity design, thus expanding application range to include lighting, display, and communication applications that require broad spectrum output
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 solution allows for the creation of white light lasers that can significantly enhance data transmission speeds, expand optical communication capacities, improve automotive lighting, and provide efficient lighting for horticulture, achieving higher color rendering indices and broader wavelength confinement.
Implementation Method 1
The imposed grating periodicity blocks propagation of light with a specific wavelength (λ) equal to twice the period (a) of the grating. The relation is known as Bragg's law
Implementation Method 2
This Bloch mirror dielectric slab resonator expands the operating wavelength of a conventional laser Bragg mirror resonator from a single wavelength to a multicolor wavelength range
Implementation Method 3
The blocked non-propagating wave (evanescent wave) can be amplified by pumping light from an adjacent active layer due to an applied voltage and current
Implementation Method 4
The disclosed periodic structure of the Bloch mirror slab confines and amplifies light propagation in a wide range of wavelengths simultaneously. The Bloch mirror may be made of a high-refractive-index material like, for example, GaN (n=2.5) with periodic first and second boundaries, which are aligned (in phase)
Data Source
AI summary
A resonator is provided having a waveguide with a first boundary, a second boundary parallel to the first boundary, a first end, a second end, and a waveguide cavity at least partly between the first boundary and the second boundary. A first grating, having a period of distance a, is at the first boundary of the waveguide, and a second grating, having a period of distance a, is at the second boundary of the waveguide. The first and second boundaries are separated by a constant distance d. The first boundary may have a periodic profile aligned with a periodic profile of the second boundary. The periodic profile of the first boundary and the second boundary may be a sinusoidal profile, a square profile, or profile of another shape. The resonator may be suitable for use in a distributed feedback laser.