Spatial Optical Transceiver Beam Spread Control for Stable Range

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Solution Overview

Problem

Existing spatial optical communication transceivers face challenges in maintaining stable communication paths over varying distances due to dynamic range issues, with solutions like variable attenuators increasing internal optical system loss and electrical gain control leading to noise fluctuations.

Innovation Solution

A spatial optical communication transceiver that adjusts the focal length of a collimator lens to maintain a constant product of free space loss and transmission gain, using a drive mechanism controlled by a drive controller to stabilize light intensity without electrical gain variation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a variable attenuator is used on the receiver side to correct light intensity variations, then the dynamic range of the light receiving element is extended, but the internal optical system loss increases and line establishment deteriorates

Engineering Contradiction:
Improvedynamic range of light receiving elementVSAvoidinternal optical system loss
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

Instead of attenuating light on the receiver side, the invention inverts the approach by amplifying light on the transmitter side using an optical amplifier. This reverses the conventional attenuation method and achieves the same goal of handling wide dynamic range while avoiding the penalty of increased optical loss in the receiver path.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The invention introduces an optical amplifier as an intermediary component on the transmitter side that actively compensates for free space loss variations. This mediator device handles the dynamic range adjustment before light enters the transmission path, preventing the need for lossy attenuation components on the receiver side.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Power

If electrical gain control of the optical amplifier is used to adjust output light intensity, then the transmission gain is adjusted, but amplified spontaneous emission is induced and noise figure deteriorates

Engineering Contradiction:
Improveoutput light intensityVSAvoidamplified spontaneous emission noise
Core Design Contradiction:
PowerVSObject-generated harmful factors

Solution Approach 1:

The invention employs a dynamically adjustable optical amplifier where the gain is controlled based on real-time distance measurements. The system adaptively adjusts amplification levels to match actual free space loss conditions, ensuring optimal signal strength while minimizing excessive amplification that would generate harmful spontaneous emission noise.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system implements a feedback mechanism where the controller receives distance information, calculates the expected free space loss, and adjusts the optical amplifier gain accordingly. This closed-loop control ensures the amplifier operates at the optimal point to compensate for path loss without over-amplifying and generating excessive noise.

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If the focal length of the collimator lens is adjusted to control beam spread angle, then the transmission gain is optimized for varying distances, but the device complexity increases

Engineering Contradiction:
Improvebeam spread angle controlVSAvoiddrive mechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention replaces complex mechanical adjustment mechanisms with an optical amplifier-based solution. Instead of using motorized lens positioning systems or variable focal length lenses that require complex drive mechanisms, the system uses electronic control of optical amplifier gain to achieve the same adaptability to varying transmission distances.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 allows for stable communication paths over varying distances without electrical gain variation, reducing noise fluctuations and maintaining signal integrity.

Implementation Method 1

a collimator including a fiber connector and a collimator lens to convert the laser beam amplified by the optical amplifier into spatial light

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

an optical telescope to enlarge a beam width of the transmission light emitted by the collimator and emit the transmission light to a spatial transmission path

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP4708726A1Spatial optical communication transceiver
Publication Date: 2026.03.11 MITSUBISHI ELECTRIC CORP
  • EP4708726A1 patent drawingFigure 1
  • EP4708726A1 patent drawingFigure 2A~3
  • EP4708726A1 patent drawingFigure 4~5

AI summary

There are provided: a light source (1101) to generate a laser beam; an optical modulator (1102) to superimpose a communication signal on the laser beam generated by the light source (1101); an OHPA (1103) to amplify the laser beam superimposed by the optical modulator (1102); a collimator (1105) including a fiber connector (11051) and a collimator lens (11052) to convert the laser beam amplified by the OHPA (1103) into spatial light, and emit transmission light that is the spatial light; an optical telescope (1108) to enlarge a beam width of the transmission light emitted by the collimator (1105) and emit the transmission light to a spatial transmission path; a drive mechanism (1112) capable of adjusting a focal length of the collimator lens (11052); and a drive controller (1113) to determine a drive amount of the drive mechanism (1112) in such a manner that a product of a free space loss calculated from a distance between the spatial optical communication transceiver and a spatial optical communication transceiver (11) as a communication counterpart and a transmission gain determined by a beam spread angle of the transmission light is constant.