Tunable Light Source Wavelength Filter Optimization
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Solution Overview
Problem
Existing wavelength monitors with 90° hybrids implemented by 4×4 MMI waveguides waste half of the input light as only two out of four output light beams are utilized, leading to inefficient light usage and increased power consumption when trying to increase light reception by the monitoring devices.
Innovation Solution
A tunable light source with a wavelength filter configured such that the maximum light output from one output port facing a light-receiving device is greater than from another, allowing increased light reception without increasing input to the wavelength filter, by adjusting the width and length of the optical coupler in the 90° hybrid to prioritize light output to unused ports for monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a 90° hybrid with 4×4 MMI is used to split light into four beams, then wavelength monitoring capability is improved, but light loss increases because only two beams are utilized
Solution Approach 1:
The patent extracts only the necessary light beams (two out of four) from the 90° hybrid output for wavelength monitoring, while discarding the redundant beams. This is achieved by selectively coupling only specific output ports of the 90° hybrid to the wavelength monitor, thereby eliminating light loss from unused beams while maintaining monitoring functionality.
Solution Approach 2:
The patent segments the light monitoring function by separating the wavelength monitoring path from the main optical signal path. By using a directional coupler to extract only the necessary portion of light for monitoring, the system achieves wavelength monitoring capability without requiring all four beams from the 90° hybrid, thus reducing light loss.
2Measurement precision
If light reception by the monitoring device is increased, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The patent applies partial action by using only the minimum necessary light beams (two out of four) from the 90° hybrid for wavelength monitoring. This partial utilization of light resources achieves sufficient measurement precision without the excessive power consumption that would result from increasing light reception beyond what is actually needed for accurate monitoring.
Solution Approach 2:
The patent discards the redundant light beams (two out of four) that would otherwise be wasted, and recovers energy by not attempting to detect or process these unnecessary beams. This selective discarding approach maintains measurement precision while avoiding the power consumption associated with processing excess light.
3Productivity
If all four output ports of the 90° hybrid are utilized, then light usage efficiency is improved, but device complexity increases
Solution Approach 1:
The patent extracts only the essential light beams (two out of four) from the 90° hybrid output for wavelength monitoring purposes. By selectively coupling only the necessary output ports to the wavelength monitor through a directional coupler, the system achieves adequate light usage efficiency without the complexity of configuring and managing all four output ports.
Solution Approach 2:
The patent segments the wavelength monitoring function to use only a subset of the available light beams. By separating the monitoring function from the complete four-beam output, the system achieves reasonable light usage efficiency while significantly reducing the complexity of the wavelength filter configuration and associated control mechanisms.
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 increases the quantity of light received by the light-receiving device while reducing wasted light, allowing for accurate wavelength control without increasing power consumption or input light, thus optimizing light usage and reducing waste.
Implementation Method 1
a 90° hybrid that is an optical divider implemented by a multi-mode interference (MMI) waveguide having four input ports and four output ports (4×4 MMI)
Implementation Method 2
a wavelength filter including multiple output ports corresponding to filtering paths through which the output light passes
Implementation Method 3
a light-receiving device that is disposed to face one of the output ports and receives light output from the one of the output ports
Data Source
AI summary
A tunable light source includes a light source; a wavelength selecting device that selects, according to a control signal, output light with a specific wavelength from light output from the light source; and a wavelength monitor including a wavelength filter including multiple output ports corresponding to filtering paths through which the output light passes, and a light-receiving device that is disposed to face one of the output ports and receives light output from the one of the output ports. The wavelength filter is configured such that a maximum quantity of the light output from the one of the output ports facing the light-receiving device becomes greater than a maximum quantity of light output from another one of the output ports.