Optical Transceiver Built-In Self-Test Loopback Structure
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Solution Overview
Problem
Current testing systems are inadequate for rapid testing and calibration of high-speed optical transceivers, which are critical for modern communication networks, as they lack efficient methods for wafer-level testing and post-manufacturing calibration.
Innovation Solution
Integration of a built-in self-test optical structure with an integrated loopback path and cascaded filters that enable loopback-based testing, allowing for wafer-level testing and post-manufacturing calibration without requiring active controls or external connections, using a wafer top emitter to tune the laser wavelength and activate tuners for accurate self-testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional testing systems are used for optical transceivers, then electronic device testing capabilities are available, but rapid testing and calibration of optical transceivers cannot be achieved
Solution Approach 1:
The patent implements a built-in self-test optical structure that enables the optical transceiver to test itself without requiring external testing equipment. The loopback path allows the transmitter to send optical signals that are routed back to the receiver, enabling autonomous testing and calibration at wafer-level and in-field, thereby achieving rapid testing while maintaining high reliability
Solution Approach 2:
The patent introduces an optical loopback path as an intermediary structure that connects the transmitter and receiver within the optical transceiver. This loopback path acts as a mediator that enables optical signal circulation for testing purposes, allowing the device to be tested using its own internal components rather than requiring external electronic testing systems
2Measurement precision
If external connections are used for testing optical transceivers, then comprehensive testing can be performed, but testing complexity and calibration operations increase
Solution Approach 1:
The patent extracts the testing functionality from external testing equipment and integrates it directly into the optical transceiver device. By incorporating the loopback path and self-test optical structure within the device itself, the patent eliminates the need for complex external connections and calibration operations while maintaining measurement precision
Solution Approach 2:
The patent merges the testing function with the operational function of the optical transceiver by integrating the loopback path into the existing transmitter-receiver architecture. This combination allows the same optical components used for data transmission to be used for testing, thereby reducing testing setup complexity while maintaining calibration 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
Enables efficient high-lane count optical transceivers to be tested and calibrated at the manufacturing stage and in the field, reducing the need for external connections and calibration operations, thereby improving testing efficiency and accuracy.
Implementation Method 1
an optical transmitter and receiver integrated on a photonic integrated circuit (PIC) to send and receive lanes of optical data
Implementation Method 2
The optical device can include a switch comprising a sequence of cascaded filters that increasingly attenuate by directing light away from the loopback path to a drop port
Implementation Method 3
Each of the filters can include a tuner that can modify the light in the filter to direct it towards the optical loopback path
Implementation Method 4
using a wafer top emitter to tune the laser wavelength and activate tuners for accurate self-testing
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
An optical device such as an optical transceiver can include a cascaded built-in self-test structure that can be configured in testing mode using an active power mode and can sufficiently attenuate light away from a loopback path in an inactive power mode. The optical device can include a wafer top emitter that can be used to tune a light source for testing and calibration of optical components while the built-in self-test structure is in active mode.