TOSA Laser Array Temperature Tilt Control
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Solution Overview
Problem
In fiber optic communications, particularly in WDM-PON systems, accurately controlling temperature across a multiplexed laser array in a TOSA package is challenging due to non-uniform temperature distribution and the need for precise wavelength precision, which is difficult to achieve with limited space and low power consumption without using temperature sensors for each laser.
Innovation Solution
Monitoring temperature at two locations within the TOSA package to determine a temperature tilt, allowing for estimated temperature calculations at other locations, and using heaters and coolers to adjust temperatures for precise wavelength tuning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature sensors are used for each laser to monitor temperature accurately, then temperature monitoring precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent divides the temperature monitoring task into two parts: (1) direct measurement at two endpoint locations using temperature sensors, and (2) indirect estimation at intermediate laser locations using the measured temperature tilt. This segmentation allows accurate temperature monitoring without placing sensors at every laser position, thereby reducing device complexity while maintaining measurement precision.
Solution Approach 2:
The patent introduces temperature tilt as an intermediary parameter that connects the directly measured temperatures at endpoint locations to the estimated temperatures at intermediate laser locations. By measuring the temperature gradient (tilt) between endpoints, the system can infer temperatures at intermediate points without direct sensing, reducing the number of sensors required.
2Manufacturing precision
If temperature sensors are installed at each laser location, then temperature control accuracy is improved, but the TOSA package size increases
Solution Approach 1:
The patent segments the temperature control approach by implementing direct temperature sensing only at two endpoint locations rather than at every laser position. Combined with thermal coupling design that creates a predictable temperature gradient across the laser array, this segmentation enables accurate temperature control for all lasers while minimizing the number of sensors and reducing package size.
Solution Approach 2:
The temperature sensors at the endpoint locations serve multiple functions: they directly monitor temperature at their respective locations and simultaneously enable indirect temperature estimation for all intermediate laser positions through temperature tilt measurement. This multi-functionality reduces the total number of sensors needed, thereby reducing package size while maintaining temperature control accuracy.
3Manufacturing precision
If multiple temperature sensors are used to monitor each laser, then wavelength precision is improved, but power consumption increases
Solution Approach 1:
The patent segments the temperature monitoring network to use sensors only at endpoint locations rather than at every laser position. This segmentation reduces the total number of active sensors and their associated power consumption while maintaining wavelength precision through the temperature tilt-based estimation method that accurately predicts temperatures at all laser locations from the endpoint measurements.
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
Enables accurate temperature control across the laser array without requiring sensors at each location, maintaining desired wavelength precision and accuracy while optimizing space and power usage.
Implementation Method 1
sensing at least first and second temperatures at first and second locations within the TOSA package
Implementation Method 2
adjusting a temperature proximate a third location along the laser array in response to the estimated temperature
Implementation Method 3
using heaters and coolers to adjust temperatures for precise wavelength tuning
Implementation Method 4
the temperature may need to be controlled within ±0.5° C. to maintain a wavelength precision of ±0.5 nm
Data Source
AI summary
The temperature at different locations along a multiplexed laser array may be monitored by sensing temperature at two locations within a transmitter optical subassembly (TOSA) package housing the laser array. The temperature at the two locations is used to determine a temperature tilt across the laser array. Estimated temperatures may then be determined at one or more other locations along the laser array from the temperature tilt. The estimated temperature(s) may then be used to adjust the temperature proximate the other locations, for example, for purposes of tuning lasers at those locations along the laser array to emit a desired channel wavelength. The TOSA package may be used in an optical transceiver in a wavelength division multiplexed (WDM) optical system, for example, in an optical line terminal (OLT) in a WDM passive optical network (PON).