Parallel Optical Transmitter Power Monitoring with Reflective Splitter
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Solution Overview
Problem
Current power monitoring techniques for parallel optical transmitters, particularly those using VCSELs, are complex, costly, and difficult to manufacture, as they require precise alignment and separate diffractive optical elements for each laser source, limiting their effectiveness in monitoring power levels and wavelength across multiple channels.
Innovation Solution
An optical power monitoring system utilizing a reflector element with a side edge that collects and splits light beams into monitor and output beams using total internal reflection, allowing simultaneous monitoring of multiple laser sources with a single reflector and array of detectors, reducing manufacturing complexity and alignment requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If diffractive optical elements are used to split the beam for power monitoring, then power monitoring capability is achieved, but manufacturing complexity and alignment difficulty increase
Solution Approach 1:
The patent extracts the beam splitting function from complex diffractive optical elements and implements it through a simple reflective element that separates the monitor beam path from the main transmission path. This extraction simplifies the optical design while maintaining the essential power monitoring capability.
Solution Approach 2:
Instead of using expensive and complex diffractive elements, the patent employs a simpler reflective element that copies the beam splitting function. This approach achieves the same functional outcome with significantly reduced manufacturing complexity and alignment requirements.
2Measurement precision
If diffractive optical elements are used for beam splitting, then power monitoring is enabled, but alignment precision requirements become more stringent
Solution Approach 1:
The patent removes the alignment-critical diffractive elements from the design and replaces them with a reflective element that inherently provides more tolerant alignment characteristics. This extraction resolves the contradiction between monitoring capability and alignment precision requirements.
3Measurement precision
If separate monitoring elements are used for each laser source, then individual power monitoring is achieved, but device complexity and cost increase
Solution Approach 1:
The patent implements a universal reflective element that serves all laser sources in the array simultaneously. This single element performs the beam splitting function for multiple channels, eliminating the need for separate monitoring elements and thereby reducing device complexity and cost while maintaining individual monitoring capability.
Solution Approach 2:
The patent merges the monitoring function for all laser sources into a single reflective element rather than using separate elements for each source. This consolidation reduces the number of components and simplifies the overall device architecture.
4Measurement precision
If conventional power monitoring techniques are used, then power levels can be monitored, but manufacturing cost and difficulty increase
Solution Approach 1:
The patent replaces expensive diffractive optical elements with a simpler, more cost-effective reflective element. This substitution maintains the power monitoring functionality while significantly reducing manufacturing cost and complexity.
Solution Approach 2:
The patent uses a simple reflective element that copies the essential beam splitting function without requiring the complex fabrication processes needed for diffractive elements, thereby improving ease of manufacture.
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 efficient, cost-effective simultaneous monitoring of power levels across multiple VCSELs, minimizing optical losses and allowing for precise control of output power, while being wavelength-independent and easier to integrate into existing systems.
Implementation Method 1
the reflector element is configured to propagate each of the monitor beams under total internal reflection from an entrance region at the side edge to an exit region of the reflector element
Data Source
AI summary
A power monitoring system uses a low loss reflective element to partially split the output laser beams from an array of laser sources, in a parallel configuration, to produce a monitor beams for each laser source. Each of these monitor beams may propagate within the reflective element in a lossless manner under total internal reflection and into one of a plurality of photodiodes that sense an optical characteristic such as output beam intensity, where this sensed signal is then used as part of a feedback control to control operation of the laser sources in the array.