Laser Apparatus Wavelength Control Using Ring Resonators
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wavelength multiplexing communication systems face limitations in increasing transmission capacity due to the need for a minimum wavelength interval greater than the modulation baud rate to prevent signal overlap, which restricts the number of wavelength channels and thus the transmission capacity.
Innovation Solution
A laser apparatus with a configuration of semiconductor optical amplifiers and ring resonators with different free spectrum ranges, allowing for independent emission of laser light with distinct wavelengths and precise control of wavelength intervals, enabling a narrower wavelength interval without signal overlap.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the wavelength interval is narrowed to increase the number of wavelength channels, then the transmission capacity increases, but the signal overlap occurs when the wavelength interval is less than or equal to the modulation baud rate
Solution Approach 1:
The patent divides the wavelength selection function into multiple independent wavelength lockers, each responsible for a specific wavelength channel. Each wavelength locker independently controls the wavelength of its corresponding laser light source, enabling precise wavelength management for multiple channels without interference. This segmentation allows the system to maintain narrow wavelength intervals while preventing signal overlap through dedicated control mechanisms.
Solution Approach 2:
The patent implements feedback control through wavelength lockers that monitor the output wavelength of each laser light source and adjust it accordingly. The wavelength locker uses a Fabry-Perot etalon to detect wavelength deviations and provides feedback to the laser light source to correct the wavelength, ensuring that each channel maintains its designated wavelength even when channels are closely spaced, thus preventing signal overlap.
2Measurement precision
If individual wavelength control is implemented using wavelength lockers, then the wavelength precision is improved, but the device complexity increases due to multiple independent control systems
Solution Approach 1:
The patent designs each wavelength locker as a universal module that can be applied to any wavelength channel. The wavelength locker structure, including the Fabry-Perot etalon and control mechanism, is standardized and can be replicated across multiple channels. This modular universal design reduces the overall system complexity by using identical components rather than custom-designed control systems for each channel, while still maintaining precise wavelength control for each individual channel.
3Reliability
If the wavelength interval is set to 50 GHz for current systems, then the signal overlap is prevented, but the number of wavelength channels is limited and transmission capacity is restricted
Solution Approach 1:
The patent changes the wavelength interval parameter from the conventional 50 GHz to a narrower interval down to the modulation baud rate (e.g., 25 GHz for 25 Gbaud systems). This parameter change is made possible by the precise wavelength control mechanism of the wavelength lockers, which ensure that even with narrower intervals, each channel maintains its designated wavelength without overlapping with adjacent channels, thereby increasing the number of available wavelength channels and transmission capacity.
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 allows for a higher number of wavelength channels and increased transmission capacity by ensuring independent operation of laser light with precise wavelength control, overcoming the limitations of existing systems.
Implementation Method 1
having a part of the light pass through a Fabry-Perot etalon by which the intensity of transmitting light changes cyclically with respect to the wavelength
Implementation Method 2
variable wavelength lasers have become indispensable devices because the oscillation wavelength can be changed in a wide wavelength range
Data Source
AI summary
A laser apparatus includes first and second gain media; first, second, and third wavelength selection filters; and first and second mirrors. The wavelengths of first and second laser light emitted from end surfaces of the first and second gain media, respectively, are different from each other. The third wavelength selection filter is a wavelength selection filter to select light having wavelengths that cyclically exist in the light, as light to be selected. The other end surfaces of the first and second gain media are connected with the first input/output ports of the first and second wavelength selection filters, respectively. The fourth input/output ports of the first and second gain media are connected with the first and second mirrors, respectively. The first and second input/output ports of the third wavelength selection filter are connected with the second input/output ports of the first and second wavelength selection filters, respectively.