Full-Duplex Laser Terminal Alignment Without Dedicated Beacon Lasers
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Solution Overview
Problem
Existing laser communication architectures require dedicated beacon lasers and optics, limiting network flexibility and increasing space, weight, and complexity, especially in satellite applications.
Innovation Solution
A laser communication terminal architecture that transmits a beacon using the same lasers and optics used for communication, with beacon modulation imposed on the transmit laser module, eliminating the need for separate beacon lasers and optics, and enabling terminals to switch between 'red' and 'blue' configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dedicated beacon lasers and optics are used for alignment, then alignment precision is improved, but device complexity and resource consumption increase
Solution Approach 1:
The patent merges the beacon function with the communication laser by using the same laser source and optical path for both alignment beacon transmission and data communication. The beacon is generated by modulating the laser at a high frequency, eliminating the need for separate beacon lasers and dedicated alignment optics, thus reducing device complexity while maintaining alignment precision
Solution Approach 2:
The laser source is designed to serve multiple functions: it acts as both the communication data carrier and the alignment beacon. By implementing multi-functionality, the system eliminates redundant components and reduces overall system complexity while maintaining the precision required for alignment through the use of frequency-modulated beacon signals
2Measurement precision
If dedicated beacon lasers are implemented, then alignment capability is improved, but space and weight increase
Solution Approach 1:
The patent combines the beacon transmission function with the existing communication laser system, using the same physical components (laser source, optical path, detector) for both purposes. This eliminates the need for separate beacon lasers and associated optics, thereby reducing the weight of the terminal while maintaining alignment capability through frequency-modulated beacons
3Reliability
If separate beacon optics are used, then beacon transmission quality is improved, but device complexity increases
Solution Approach 1:
The optical path is designed to be universal, handling both beacon transmission and data communication through the same components. The beacon is transmitted by modulating the laser at a high frequency, allowing the same optical path to distinguish between beacon and data signals through frequency filtering, thereby maintaining transmission quality without adding complexity
4Use of energy by moving object
If beacon power is reduced during communication phase, then power consumption is reduced, but alignment maintenance precision may deteriorate
Solution Approach 1:
The system uses periodic modulation of the laser at high frequency to encode the beacon signal. This allows the beacon to be transmitted at the same power level as communication signals, enabling continuous alignment maintenance without requiring separate high-power beacon transmissions, thus managing power consumption while maintaining precision through efficient signal encoding
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 precise alignment and flexible reconfiguration of the network without dedicated beacon lasers, reducing complexity and resource consumption while maintaining high-speed, secure communication.
Implementation Method 1
a transmit laser module that is configured to emit transmit laser light at a first communication wavelength
Implementation Method 2
impose a beacon modulation onto the transmit laser light that enables the transmit laser light, when transmitted at or near the first communication wavelength as an alignment beacon
Implementation Method 3
a receive filter module configured to pass light that is at or near a second communication wavelength with minimal attenuation while excluding light at all other wavelengths
Implementation Method 4
an acquisition and track sensor ('ATS') configured to derive tracking information from beacon laser light received from the remote terminal
Implementation Method 5
a receive beam splitter configured to apportion the beacon laser light and the communication laser light between the ATS and the communication detector
Data Source
Figure 1A
Figure 1B
Figure 1C~1D
AI summary
A laser communication architecture provides precise optical alignment between terminals without requiring dedicated beacon lasers or dedicated beacon wavelength optics. Instead, the same lasers and optics are used for both alignment and communication. A beacon modulation is applied to alignment beacons transmitted at or near communication wavelengths so as to differentiate them from communication beams. The beacon modulation can include phase and/or amplitude variation of a high frequency modulation, and/or "ping-pong" toggling of the beacon wavelength. In some full duplex red/blue embodiments, ping-pong modulation is implemented by alternated red/blue tuning of the transmit laser or by switching between separate red and blue transmit lasers, for example using a 2x1 laser switch, while maintaining constant beacon amplitude, thereby avoiding optical amplifier dynamic response issues. During communication, embodiments maintain optical alignment by diverting a percentage of received communication light to the tracking sensor.