Optical Phase Modulator Layout for Low-Loss Coupling and Fast Testing

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Solution Overview

Problem

Existing optical phase modulators suffer from high optical coupling losses due to passive waveguides with high optical confinement factors, and testing these modulators requires precise alignment of optical fibers, leading to increased time and complexity.

Innovation Solution

A semiconductor optical phase modulator design with first and second semiconductor optical amplifiers having reduced optical confinement factors, and a testing method using forward and reverse bias voltages to compare test light intensity without separate test equipment alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If passive waveguides with high optical confinement factor are used in the optical phase modulator, then the optical confinement factor is improved, but the optical coupling loss increases

Engineering Contradiction:

Improveoptical confinement factorVSAvoidoptical coupling loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent changes the optical confinement factor parameter from high (in passive waveguides) to low (in semiconductor optical amplifiers). By designing the SOAs with low optical confinement factors, the mode field diameter is increased, which enables better coupling with optical fibers and reduces optical coupling loss while maintaining adequate optical confinement for amplification functionality.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If precise alignment of optical fibers is performed during testing, then the measurement precision is improved, but the testing time increases

Engineering Contradiction:

Improvealignment precisionVSAvoidtesting time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent enables the optical phase modulator to perform self-testing by utilizing its own semiconductor optical amplifiers to generate and detect test light. This self-service approach eliminates the need for external test equipment and complex alignment procedures, allowing rapid testing without precise fiber alignment while maintaining measurement accuracy through the device's inherent optical paths.

Inventive Principle:

Principle #25Self-service

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

Reduces optical coupling losses and simplifies the testing process by eliminating the need for separate test equipment alignment, thereby shortening testing time and improving efficiency.

Implementation Method 1

a first semiconductor optical amplifier to amplify light input to the optical phase modulation element

Methodology Applied

Scientific EffectStimulated emission:

Implementation Method 2

a second semiconductor optical amplifier to amplify modulated signal light output from the optical phase modulation element

Methodology Applied

Scientific EffectStimulated emission:

Implementation Method 3

a first core layer having a first multiple quantum well structure

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentUS12578614B2Semiconductor optical phase modulator and method of testing the same

Publication Date: 2026.03.17 MITSUBISHI ELECTRIC CORP

AI summary

A semiconductor optical phase modulator includes an optical phase modulation element, a first semiconductor optical amplifier to amplify light input to the optical phase modulation element, and a second semiconductor optical amplifier to amplify modulated signal light output from the optical phase modulation element. A light input end of the semiconductor optical phase modulator is a light input end face of the first semiconductor optical amplifier. A light output end of the semiconductor optical phase modulator is a light output end face of the second semiconductor optical amplifier.