Optical Module Wavelength Control With Integrated Optical Monitoring
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Solution Overview
Problem
Existing optical modules with single-wavelength semiconductor lasers require a large number of components and a significant size due to the need for Peltier elements, etalons, and collimating components, which complicates precise wavelength control and downsizing.
Innovation Solution
An optical module design that includes a semiconductor laser, an optical monitor with a first and second optical receiver, and a temperature adjuster to control the temperature of both the semiconductor laser and the optical monitor, allowing for precise control of the wavelength by adjusting the temperature based on the ratio of optical power and wavelength monitor values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Peltier element and etalon are used for wavelength control, then wavelength precision is improved, but device complexity and size increase
Solution Approach 1:
The patent combines the wavelength control function and optical monitoring function into a single integrated optical monitor unit. The optical monitor includes both the first optical receiver for power monitoring and the second optical receiver with etalon for wavelength monitoring, eliminating the need for separate Peltier elements and external etalon assemblies. This merging reduces component count while maintaining wavelength control precision through integrated temperature adjustment.
2Stability of the object's composition
If an etalon and collimating components are added for wavelength locking, then wavelength stability is improved, but device size increases
Solution Approach 1:
The patent nests the etalon and optical receivers within the integrated optical monitor unit, which itself is mounted on the semiconductor laser housing. The optical monitor is positioned to receive backward-emitted light from the laser, creating a nested configuration where monitoring components are embedded within the existing laser structure rather than adding external assemblies. This nesting approach maintains wavelength stability while minimizing volume increase.
3Measurement precision
If separate Peltier elements are provided for laser and etalon temperature control, then wavelength control accuracy is improved, but device complexity increases
Solution Approach 1:
The patent makes the optical monitor unit serve multiple functions: it monitors optical power through the first optical receiver, monitors wavelength through the second optical receiver with etalon, and provides integrated temperature control for both the semiconductor laser and etalon through a single temperature adjuster mechanism. This multi-functionality reduces the need for separate temperature control systems while maintaining control accuracy.
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 design achieves precise control of a single wavelength, reduces the number of components, and enables downsizing of the optical module, while maintaining effective wavelength control and optical power monitoring.
Implementation Method 1
a temperature adjuster to adjust a temperature in the semiconductor laser and a temperature in the optical monitor
Implementation Method 2
an optical filter to receive the laser beam from the semiconductor laser
Implementation Method 3
a first optical receiver to receive a laser beam from the semiconductor laser
Implementation Method 4
a second optical receiver to receive the laser beam via the optical filter
Data Source
AI summary
An optical module includes a semiconductor laser, a first optical receiver receiving a laser beam from the semiconductor laser, an optical filter receiving the laser beam, and a second optical receiver receiving the laser beam via the optical filter, and a temperature adjuster adjusting a temperature in the semiconductor laser and a temperature in the optical monitor, and perform control to increase a temperature to be given to the semiconductor laser and the optical monitor when a wavelength monitor value Iλ/Ip being a ratio between an optical power monitor value Ip obtained by an output from the first optical receiver and a wavelength monitor value Iλ obtained by an output from the second optical receiver is larger than a wavelength set value, and change the temperature to be given to the semiconductor laser and the optical monitor when the wavelength monitor value Iλ/Ip deviates from the wavelength set value.