Photonic Crystal Laser Frequency Modulation for High S/N Signaling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing two-dimensional photonic crystal lasers face challenges in achieving high signal-to-noise ratio (S/N) for long-distance and high-frequency optical communication due to limitations in increasing modulation amplitude and conversion efficiency when modulation frequency is increased.
Innovation Solution
The laser is designed with a two-dimensional photonic crystal layer divided into multiple electric current injection regions, each with distinct resonance frequencies, and a signal electric current is supplied to these regions with varying intensity ratios over time, creating a temporal change in the total resonance frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the modulation frequency is increased to communicate large quantity of information, then the information transmission rate is improved, but the conversion efficiency from signal electric current to signal light decreases and the modulation amplitude cannot be sufficiently increased
Solution Approach 1:
The patent divides the photonic crystal laser into multiple independent electric current injection regions (first, second, third regions) with different resonance frequencies. Each region can be independently modulated, allowing parallel signal processing that increases information transmission rate while maintaining efficient conversion in each region.
Solution Approach 2:
Each electric current injection region is designed with specific local properties (different resonance frequencies, different active layer structures) to optimize its function. The first region has higher conversion efficiency, the second and third regions have different resonance characteristics, allowing each local region to operate at optimal efficiency for its designated frequency range.
2Reliability
If the amplitude of signal electric current is increased to improve modulation amplitude, then the signal quality is improved, but it becomes difficult to increase the amplitude when modulation frequency is increased
Solution Approach 1:
The signal current is divided into multiple independent channels (first, second, third signal electric currents) that can be independently controlled. This segmentation allows each channel to maintain optimal amplitude for its frequency range while collectively achieving high information transmission rates.
Solution Approach 2:
The patent dynamically assigns different resonance frequencies to different injection regions and modulates each region at its optimal frequency. This dynamic approach allows the system to maintain high conversion efficiency and signal quality across varying operating conditions by matching each region's modulation frequency to its resonance characteristics.
3Device complexity
If a single resonance frequency is used in the photonic crystal layer, then the device structure is simple, but the signal-to-noise ratio cannot be sufficiently high for long-distance communication
Solution Approach 1:
The photonic crystal layer is segmented into multiple electric current injection regions with different resonance frequencies. This segmentation enables frequency-division multiplexing, where multiple signals at different frequencies can be transmitted simultaneously, improving signal-to-noise ratio through frequency diversity while maintaining a relatively simple overall structure.
Solution Approach 2:
The patent changes the resonance frequency parameter across different regions of the photonic crystal layer. By creating a frequency gradient (first region: higher frequency, second and third regions: lower frequencies), the system achieves better signal-to-noise ratio through frequency diversity, allowing long-distance communication with reduced interference.
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 design enables high S/N ratio optical signal transmission by modulating the laser light's frequency, allowing for efficient data transmission with improved signal quality.
Implementation Method 1
out of light generated in the active layer, only light of a predetermined resonance frequency resonates and laser oscillates in the two-dimensional photonic crystal layer
Implementation Method 2
laser oscillates in the two-dimensional photonic crystal layer, and laser light is emitted
Implementation Method 3
The two-dimensional photonic crystal layer has a configuration including a plate-shaped base member in which different refractive index portions whose refractive index differs from that of the base member are periodically disposed two-dimensionally
Implementation Method 4
different refractive index portions whose refractive index differs from that of the base member
Implementation Method 5
The active layer generates light emission with a specific wavelength band upon being supplied with carriers (positive holes, electrons) from the electrode pair
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Provided is a two-dimensional photonic crystal laser capable of transmitting a signal by laser light at a high S/N ratio. A two-dimensional photonic crystal laser (10) includes an active layer (11), a two-dimensional photonic crystal layer (12) having a two-dimensional photonic crystal structure in which a different refractive index portion (122), which is a portion having a refractive index different from a refractive index of a plate-like base member (121) laminated directly with the active layer (11) or with another layer, is two-dimensionally and periodically disposed in the base member (121), the two-dimensional photonic crystal layer (12) having a plurality of electric current injection regions (1201, 1202) having different resonance frequencies from each other, and an electric current supply unit (split electrode (172)) configured to supply a signal electric current in which a ratio of electric current intensity between the plurality of electric current injection regions (1201, 1202) changes with time into each of the plurality of electric current injection regions.