Single-Fiber Optical Transceiver Module with Edge-Mounted Light Source
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Solution Overview
Problem
Existing single-fiber optical transceiver modules face challenges in achieving high optical coupling efficiency while minimizing optical crosstalk and complexity, particularly when co-locating the photodiode and laser diode, which often requires complex optical coupling systems and increases module size and cost.
Innovation Solution
A half-duplex single-fiber optical transceiver module design where the photodiode and light source are co-located with a simple optical coupling system, featuring a lens portion and alignment portion within a transparent molded encapsulation, allowing for efficient light transmission and reception with reduced crosstalk by positioning the light source on the edge of the photodiode and using a bent leadframe to optimize optical alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the laser diode and photodiode are spatially separated to reduce optical crosstalk, then optical crosstalk is reduced, but the module size increases and complex optical coupling systems are required
Solution Approach 1:
The patent merges the laser diode and photodiode into the same IC package, co-locating them in close proximity. This eliminates the need for spatial separation while managing optical crosstalk through precise optical coupling design rather than physical distance.
Solution Approach 2:
The patent introduces an optical coupling system with lens elements as intermediaries between the laser diode and photodiode. These optical components mediate the light paths, enabling efficient coupling while preventing direct optical interference between the co-located devices.
2Volume of stationary object
If the laser diode and photodiode are co-located to reduce module size, then module size is reduced, but complex optical coupling systems are required to prevent optical crosstalk
Solution Approach 1:
The optical coupling system is merged with the molded encapsulation structure itself. The lens elements are integrated directly into the encapsulation, eliminating separate optical coupling components and simplifying the overall device architecture.
Solution Approach 2:
The molded encapsulation serves multiple functions: it provides structural support, electrical insulation, and optical coupling functionality through integrated lens elements. This multi-functionality reduces the need for separate dedicated components.
3Volume of stationary object
If co-location of laser diode and photodiode is implemented, then module size is reduced, but optical coupling efficiency for received light decreases due to laser diode blocking received light
Solution Approach 1:
The patent positions the laser diode and photodiode at different locations within the same IC package, utilizing different regions of the package substrate. This spatial arrangement within the co-located structure allows received light to reach the photodiode without being blocked by the laser diode, while still achieving compact integration.
Solution Approach 2:
Optical coupling lenses are positioned as intermediaries to redirect and focus received light onto the photodiode surface, ensuring that the light path is optimized and not obstructed by the co-located laser diode structure.
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 configuration achieves high optical coupling efficiency for both transmit and receive signals with reduced optical crosstalk, using a simpler optical coupling system and allowing for the use of LEDs instead of laser diodes, thereby decreasing module size and cost while maintaining effective performance.
Implementation Method 1
the lens portion is configured to optically couple light passing out of the first end face of the optical fiber onto the upper light-receiving surface of the photodiode and to optically couple light emitted from the upper light-emitting surface of the light source onto the end face of the optical fiber
Implementation Method 2
a photodetector, which is typically a photodiode, detects optical data signals transmitted over an optical fiber and converts the optical data signals into electrical data signal
Implementation Method 3
a light source is modulated based on an electrical data signal and generates corresponding optical data signals. The light source is typically a laser diode, but is sometimes a light emitting diode (LED)
Data Source
AI summary
A half-duplex, single-fiber (S-F) optical transceiver module is provided in which a light source, such as a laser diode or a light-emitting diode (LED), is mounted on an edge region of a photodiode to increase the amount of surface area of the photodiode that is available for absorbing light received in the optical transceiver module. The S-F optical transceiver module has a relatively simple optical coupling system for coupling light between an end face of an optical fiber and the photodiode and laser diode or LED with high optical coupling efficiency and reduced optical crosstalk.