Wavelength-Multiplexed Light Transmission Module Using Single Lens and Filter
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Solution Overview
Problem
The existing wavelength-multiplexed light transmission modules face challenges in miniaturization due to complex structures, high manufacturing costs, and increased productivity issues caused by the need for multiple collimating lenses and bandpass filters, which complicate optical axis adjustment and fixation, leading to increased chip size and manufacturing time.
Innovation Solution
A wavelength-multiplexed light transmission module design that uses a single lens and a single bandpass filter, where laser beams with different wavelengths are radially emitted and incident at varying angles, allowing for multiplexing through a single bandpass filter and inclined mirror, reducing the need for multiple optical components and simplifying the structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple collimating lenses and bandpass filters are used to multiplex laser beams, then the wavelength multiplexing function is achieved, but the structure becomes complicated and manufacturing time increases
Solution Approach 1:
The patent merges multiple bandpass filters into a single integrated filter that handles multiple wavelengths simultaneously. Instead of using separate collimating lenses and bandpass filters for each wavelength, the invention uses one collimating lens and one multi-wavelength bandpass filter with specific transmission characteristics, thereby simplifying the overall structure while maintaining wavelength multiplexing capability
Solution Approach 2:
The bandpass filter is designed to perform multiple functions: it simultaneously separates and transmits multiple laser wavelengths (e.g., 1310nm and 1550nm) while reflecting others. This multi-functional filter replaces what would traditionally require multiple separate filters, reducing structural complexity without compromising adaptability
2Adaptability or versatility
If multiple collimating lenses and bandpass filters are used, then wavelength multiplexing is achieved, but manufacturing time and labor increase due to repeated optical axis adjustment
Solution Approach 1:
By combining multiple filtering functions into a single bandpass filter, the number of optical axis adjustment operations is reduced from multiple (one per filter) to a single adjustment, significantly decreasing manufacturing time and labor requirements while maintaining the wavelength multiplexing function
3Reliability
If multiple metal holders are welded to fix optical components, then reliable fixation is achieved, but additional laser radiation and adjustment become difficult after welding
Solution Approach 1:
The invention reduces the number of metal holders from multiple (one per filter) to a single holder that supports the integrated multi-wavelength bandpass filter. This simplifies the welding process to a single operation and maintains post-weld adjustability, as fewer welded joints mean less complexity in subsequent adjustment procedures
4Reliability
If adhesive agent is used to fix collimating lenses, then fixation is achieved, but hardening shrinkage and time-dependent shape changes occur
Solution Approach 1:
The patent reduces the number of collimating lenses from multiple to a single lens, thereby reducing the number of adhesive bonding operations. This minimizes the cumulative effect of adhesive shrinkage and time-dependent shape changes, maintaining better optical alignment precision while achieving reliable fixation
5Reliability
If each collimated light is independently configured by separate collimating lenses, then optical performance is maintained, but the interval between laser emitting waveguides becomes large (1 mm or more)
Solution Approach 1:
The invention merges multiple independent optical paths into a single integrated optical system with one collimating lens and one multi-wavelength bandpass filter. This allows the laser emitting waveguides to be positioned closer together (reducing chip size) while maintaining optical performance through the shared optical components
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 enables miniaturization of the wavelength-multiplexed light transmission module, reduces manufacturing costs, and facilitates easier optical axis adjustment, while maintaining high accuracy and productivity, allowing for more compact integration of laser diodes and efficient multiplexing of laser beams.
Implementation Method 1
a lens to which the plurality of laser beams are incident, the lens radially emitting the plurality of laser beams
Implementation Method 2
a bandpass filter that is provided in a light emitting direction of the lens and has a transmission center wavelength which is shorter as an incident angle is larger
Implementation Method 3
a mirror that is provided to be inclined with respect to the bandpass filter in a light emitting direction of the bandpass filter and has a reflecting surface for reflecting the plurality of laser beams
Data Source
AI summary
A wavelength-multiplexed light transmission module according to the present invention includes a plurality of lasers that respectively emit a plurality of laser beams having different wavelengths, a lens radially emitting the plurality of laser beams, a bandpass filter that has a transmission center wavelength which is shorter as an incident angle is larger, and a mirror for reflecting the plurality of laser beams, wherein the plurality of laser beams are incident to the bandpass filter such that the incident angle of a laser beam is larger as the laser beam has a shorter wavelength, whereby the plurality of laser beams are transmitted through the bandpass filter, and an inclination angle of the mirror with respect to the bandpass filter is provided such that the plurality of laser beams transmitted through the bandpass filter are reflected by the bandpass filter and the mirror to be multiplexed with one another.