Optical Transmitter Module Lens Positioning for Power Control
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Solution Overview
Problem
Optical transmitter modules with multiple channels face challenges in adjusting optical power output due to de-focusing, which affects coupling efficiency between laser diodes and optical fibers, leading to inconsistent or excessive optical power levels across different channels.
Innovation Solution
The optical transmitter module employs a three-lens system with pre-focusing and adjusting lenses to optimize optical power coupling, where the adjusting lenses are positioned to ensure collimated beams are focused onto the optical fiber, allowing for independent adjustment of optical output power across multiple channels without compromising coupling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If de-focusing is performed to reduce optical power output, then optical power level is reduced, but coupling efficiency between LD and optical fiber deteriorates and high-frequency performance degrades
Solution Approach 1:
The patent divides the optical adjustment function into separate components for each lane: individual adjusting lenses (14a-14d) are provided for each laser diode, allowing independent optimization of coupling efficiency and optical power output for each channel without affecting others
Solution Approach 2:
The patent applies different optical configurations to different parts of the system: each lane has its own adjusting lens positioned at specific locations (first position for collimated beams, second position for dispersive beams), allowing localized optimization of optical properties for each channel
2Power
If de-focusing is performed for one channel to adjust optical power, then optical power for that channel is reduced, but optical power for other channels becomes inconsistent or exceeds specifications
Solution Approach 1:
The patent provides independent adjusting lenses (14a-14d) for each lane, enabling separate adjustment of optical power for each channel. This segmentation allows each channel to be optimized independently while maintaining consistency across all channels
Solution Approach 2:
The patent changes the position parameter of adjusting lenses along the optical axis to control optical power output. By moving each adjusting lens to different positions (first position for collimated, second position for dispersive), the optical power for each channel can be precisely controlled to meet specifications
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 approach enables precise adjustment of optical output power for each channel, ensuring compliance with standards like IEEE 100 GBASE-LR4 by maintaining optimal coupling efficiency and reducing optical loss, while accommodating temperature variations and alignment tolerances.
Implementation Method 1
placing the adjusting lens on a point at which the optical signal passing through the adjusting lens becomes a collimated beam
Implementation Method 2
an optical fiber, which couples with the adjusting lens through a concentrating lens
Data Source
AI summary
An optical transmitter module that generates a signal multiplexing two or more optical signals each having optical power satisfying a preset magnitude is disclosed. The optical transmitter module includes laser diodes (LD), adjusting lenses coupled with the LDs to generate dispersive optical outputs, and a concentrating lens that concentrates the dispersive optical beams onto a coupling fiber. A feature of the optical transmitter module is that the adjusting lenses are set closer to the LDs to adjust the optical power coupled with the coupling fiber.