Optical Coherent Imager with Shared Polarization-Diverse Path
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional optical coherent imagers using photonic integrated circuits (PICs) face challenges in efficiently sharing optical paths for transmitting and receiving signals, leading to complex optical systems and high manufacturing costs, particularly in finite-field illumination approaches.
Innovation Solution
An optical coherent imager with a shared input-output path utilizing polarization diversity, implemented on a PIC, where polarization-diversified optical couplers and transformers enable simultaneous transmission and reception of optical signals, simplifying the design and calibration by directing signals with different polarization states to separate waveguides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate optical systems are used for transmitting and receiving signals in finite-field illumination, then signal transmission and reception can be performed independently, but the optical system complexity and manufacturing cost increase
Solution Approach 1:
The patent combines the transmitting and receiving optical paths into a single shared optical system. The photonic integrated circuit uses the same optical path for both transmitting illumination signals and receiving reflected signals, eliminating the need for separate optical systems. This merging reduces device complexity and manufacturing cost while maintaining functional independence through polarization diversity.
Solution Approach 2:
The optical path in the photonic integrated circuit is designed to serve multiple functions: it acts as both a transmission path for illumination signals and a reception path for reflected signals. This multi-functionality is achieved through polarization-diversified optical couplers that can handle both outgoing and incoming signals through the same physical path, reducing the number of components needed.
2Productivity
If full-field illumination is used, then the sensor can acquire images at high frame rates with simplified data processing, but laser power is spread over a large area resulting in fewer photons per sensing unit
Solution Approach 1:
The patent implements finite-field illumination where laser power is concentrated on specific sensing units rather than spread across the entire sensor array. The illumination is directed to localized regions, increasing the photon density at each sensing unit. This local quality approach allows the system to operate at longer distances while maintaining sufficient signal strength for detection.
3Device complexity
If polarization-diversified optical couplers are used to share input-output paths, then the optical system is simplified and manufacturing costs are reduced, but signals with different polarization states must be directed to separate waveguides
Solution Approach 1:
The patent segments the optical signal handling by polarization state. Polarization-diversified optical couplers separate incoming and outgoing signals based on their polarization states, directing them to different waveguides within the photonic integrated circuit. This segmentation allows the system to use a shared optical path while maintaining signal integrity through polarization-based routing, simplifying the overall optical system architecture.
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 simplifies the optical system, reduces manufacturing costs, and enhances efficiency by concentrating laser power on specific sensing units, allowing operation over longer distances and improving signal detection.
Implementation Method 1
polarization diversity... directing signals with different polarization states to separate waveguides
Implementation Method 2
optical coherent detection (also called optical heterodyne detection)... coherently combining the LO with the target signal
Implementation Method 3
detection by photodetectors
Data Source
AI summary
The present disclosure provides an optical coherent imager implemented on a photonic integrated circuit (PIC) that enables shared path for transmitting and receiving optical signals by exploiting polarization diversity. The present disclosure also provides an optical coherent imager including an array of the optical coherent sensing units to simplify the design and calibrations of the imager, and a method for coherent sensing by the optical coherent imager.