Heated Laser Package Thermal Efficiency in WDM-PON Transmitters
Solution Overview
Problem
Existing optical transmitters in WDM-PON systems face challenges in providing adequate temperature control for laser arrays within a small form factor and low power consumption, requiring complex and costly circuit designs for individual temperature control of each laser diode, which is not feasible in a multi-channel TOSA.
Innovation Solution
A heated laser package is introduced, comprising a laser diode, a heating resistor, and a transistor in a single package, where the transistor controls the drive current to the heating resistor, and any additional heat generated contributes to the thermal efficiency, allowing for global and local temperature control of the laser array using a TEC cooler and individual heaters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If individual temperature control devices (TEC coolers and thermistors) are used for each laser diode, then temperature control precision is improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent combines the TEC cooler, thermistor, and heating resistor into a single integrated temperature control device that serves multiple laser diodes simultaneously. This merging approach maintains temperature control precision while reducing the number of separate components and simplifying the overall circuit design compared to using individual control devices for each laser diode.
Solution Approach 2:
The integrated temperature control device is designed to provide both cooling (via TEC cooler) and heating (via heating resistor) functions while monitoring temperature (via thermistor) for multiple laser diodes. This multi-functional approach allows a single device to perform what previously required multiple separate components, reducing complexity while maintaining control precision.
2Measurement precision
If individual temperature control devices are used for each laser diode, then temperature control precision is improved, but the form factor becomes too large
Solution Approach 1:
By merging the TEC cooler, thermistor, and heating resistor into a single integrated device, the patent significantly reduces the space required for temperature control components. This allows precise temperature control of multiple laser diodes within a compact form factor suitable for small-scale optical modules.
3Measurement precision
If individual temperature control devices are used for each laser diode, then temperature control precision is improved, but power consumption increases
Solution Approach 1:
The integrated temperature control device allows for shared thermal management resources among multiple laser diodes. By consolidating the TEC cooler and heating resistor, the system can more efficiently manage power distribution and reduce redundant power consumption that would occur with multiple separate control devices.
4Area of stationary object
If a compact form factor is used for the TOSA, then integration density is improved, but temperature control capability deteriorates
Solution Approach 1:
The patent successfully integrates temperature control functionality into a compact form factor by merging the TEC cooler, thermistor, and heating resistor into a single device. This integration maintains reliable temperature control capability while achieving the compact size needed for dense TOSA configurations.
Solution Approach 2:
The integrated temperature control device acts as an intermediary component that provides precise temperature control for multiple laser diodes within a compact space. This mediator approach enables reliable thermal management in the constrained environment of a compact TOSA without requiring individual control devices for each laser.
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 solution enables precise temperature control of laser diodes with reduced power consumption and simplified circuit design, maintaining wavelength precision within ±0.05 nm across 16 channels, while fitting within a compact form factor.
Implementation Method 1
a heating resistor located proximate to the laser diode and configured to raise a local temperature of the laser diode above a global temperature of the TOSA to thermally tune the laser diode
Implementation Method 2
a transistor configured to adjust a drive current through the heating resistor, the drive current based on a temperature control signal provided by the temperature control circuit
Implementation Method 3
a laser diode configured to generate laser light from power provided by a laser driver. The laser light is associated with a respective optical channel and the laser diode is thermally tunable to a channel wavelength
Implementation Method 4
allowing for global and local temperature control of the laser array using a TEC cooler and individual heaters
Data Source
AI summary
A heated laser package generally includes a laser diode, a heating resistor and a transistor in a single laser package. The heating resistor and transistor form a heating circuit and may be located on a submount adjacent to the laser diode. The transistor is configured to control the drive current to the heating resistor and any additional heat generated by the transistor may contribute to the heating of the laser diode and thus increase the thermal efficiency of the system. The heated laser package may be used in a temperature controlled multi-channel transmitter optical subassembly (TOSA), which may be used in a multi-channel optical transceiver. The optical transceiver may be used in a wavelength division multiplexed (WDM) optical system, for example, in an optical line terminal (OLT) in a WDM passive optical network (PON).