WDM Transmitter Receiver Temperature Control Wavelength Adjustment
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Solution Overview
Problem
In multi-wavelength lasers for wavelength division multiplexing communication systems, manufacturing errors can cause oscillation wavelengths to deviate from design values, requiring precise control of transmission wavelengths, which is complex and inefficient.
Innovation Solution
A wavelength division multiplexing communication system with a transmitter and receiver maintained at constant temperature, utilizing a semiconductor optical amplifier, wavelength demultiplexing and multiplexing filters with constant transmission wavelength intervals, reflection structures, and modulators, along with a temperature controller for the receiver's wavelength demultiplexing filter to adjust and maintain optimal communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a multi-wavelength laser is used in WDM system, then the number of lasers required is reduced, but manufacturing errors cause oscillation wavelengths to deviate from design values
Solution Approach 1:
A wavelength adjustment mechanism is introduced as an intermediary component between the multi-wavelength laser and the WDM system. This mechanism includes a wavelength filter with adjustable transmission wavelengths that can compensate for manufacturing errors in the laser, allowing the oscillation wavelengths to be precisely tuned to match the WDM grid requirements
Solution Approach 2:
The transmission wavelengths of the wavelength filter are made adjustable through parameter changes. By controlling the refractive index of the wavelength filter (e.g., through temperature control or electro-optic effects), the transmission wavelengths can be dynamically adjusted to compensate for manufacturing deviations and achieve precise wavelength alignment
2Manufacturing precision
If heating elements are added to control transmission wavelengths of wavelength filter, then wavelength accuracy is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
Instead of adding complex heating elements, the patent uses parameter changes in the wavelength filter's refractive index through simpler means such as temperature control or electro-optic effects. This achieves precise transmission wavelength control while minimizing additional device complexity
Solution Approach 2:
The wavelength filter is designed to have built-in wavelength adjustment capability through its material properties or structure. The filter can self-adjust its transmission wavelengths in response to environmental changes or control signals, reducing the need for external complex control mechanisms
3Manufacturing precision
If transmission wavelengths of wavelength filter are precisely controlled, then oscillation wavelength accuracy is improved, but ease of manufacture decreases
Solution Approach 1:
The adjustable wavelength filter serves as a mediator that decouples the manufacturing precision requirements. The laser can be manufactured with standard tolerances, and the wavelength filter subsequently adjusts the oscillation wavelengths to match the required precision, making the overall system easier to manufacture
Solution Approach 2:
The wavelength filter is pre-configured with adjustable transmission wavelength characteristics that can be tuned after assembly. This preliminary design approach allows standard manufacturing processes to be used, with precise wavelength control achieved through subsequent adjustment rather than requiring ultra-precise manufacturing
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 eliminates the need for precise oscillation wavelength control in multi-wavelength lasers, simplifying the system, improving productivity, and allowing for manufacturing variations, while ensuring effective communication by adjusting transmission wavelengths on the receiver side.
Implementation Method 1
a semiconductor optical amplifier having a reflection mirror at a first end of the semiconductor optical amplifier
Implementation Method 2
a first wavelength demultiplexing filter having an input port coupled to a second end of the optical waveguide and a plurality of output ports having constant transmission wavelength intervals
Implementation Method 3
reflection structures to reflect part of light output from the output ports, the reflection structures provided for the respective output ports of the first wavelength demultiplexing filter
Implementation Method 4
modulators to modulate light transmitted through the reflection structures, the modulators provided for the respective reflection structures
Implementation Method 5
a wavelength multiplexing filter having input ports coupled to output ends of the modulators, transmission wavelength intervals of the input ports being identical to the transmission wavelength intervals of the first wavelength demultiplexing filter
Implementation Method 6
a temperature controller to control temperature of the second wavelength demultiplexing filter
Implementation Method 7
transmission wavelengths of the wavelength filter are controlled by controlling the refractive index of the wavelength filter by the thermo-optic effect
Data Source
AI summary
Included are a transmitter and a receiver caused to have a constant temperature. The transmitter includes: a semiconductor optical amplifier having a reflection mirror at a first end thereof; an optical waveguide having a first end coupled to a second end of the semiconductor optical amplifier; a wavelength demultiplexing filter having an input port coupled to a second end of the optical waveguide and a plurality of output ports having constant transmission wavelength intervals; reflection structures to reflect part of light output from the output ports, the reflection structures provided for the respective output ports of the wavelength demultiplexing filter; modulators to modulate light transmitted through the reflection structures, the modulators provided for the respective reflection structures; and a wavelength multiplexing filter having input ports coupled to the respective output ends of the modulators, transmission wavelength intervals of the input ports being identical to the transmission wavelength intervals of the wavelength demultiplexing filter, and having the output port coupled to a first end of an optical fiber. The receiver includes: a wavelength demultiplexing filter having an input port coupled to a second end of the optical fiber and a plurality of output ports having the same transmission wavelength intervals as the transmission wavelength intervals of the wavelength demultiplexing filter and an FSR obtained by multiplying the transmission wavelength interval by the number of the output ports; light receivers to receive light output from the output ports, the light receivers provided for the respective output ports of the wavelength demultiplexing filter; and a temperature controller to control the temperature of the wavelength demultiplexing filter.