Optical Module Electrode Routing for Relay Substrate Size Reduction

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Solution Overview

Problem

The increasing complexity of optical modulators for multivalued and polarization-multiplexed optical communication systems leads to a significant increase in the size of the relay substrate due to the doubling of signal paths and components, resulting in a larger module size.

Innovation Solution

The optical module design includes a waveguide substrate with multiple electrodes connected through a relay substrate and a termination substrate, where the electrodes are divided into two groups extending in opposite directions, allowing for a compact layout that reduces the size of the termination substrate and the housing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If two sets of Mach-Zehnder modulating units are disposed to achieve multivalued and polarization-multiplexed optical communication, then the modulation capacity is improved, but the relay substrate size is increased due to doubled signal paths and components

Engineering Contradiction:

Improvemodulation capacityVSAvoidrelay substrate size

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The electrode wiring is divided into two distinct groups: a first group extending in a first direction along the optical waveguide and a second group extending in a direction opposite to the first direction. This segmentation allows independent routing of different signal paths, reducing interference and enabling compact layout of multiple Mach-Zehnder modulating units on the relay substrate without proportionally increasing its size

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent transitions from a conventional linear arrangement of electrodes to a bidirectional arrangement where wiring extends in opposite directions from a central point. This dimensional change in wiring topology allows more efficient use of substrate space, accommodating doubled signal paths without linearly increasing the relay substrate area

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If the number of signal paths is doubled to support multivalued and polarization-multiplexed modulation, then the communication capacity is improved, but the number of RF terminals, DC terminals, capacitors, bias resistors, and termination resistors is doubled, requiring more mounting space

Engineering Contradiction:

Improvecommunication capacityVSAvoidnumber of components

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Multiple electrode wiring paths are merged into a shared relay substrate infrastructure. The bidirectional wiring groups share common mounting areas for capacitors, bias resistors, and termination resistors, allowing multiple signal paths to coexist on the same substrate without requiring separate dedicated spaces for each component set

Inventive Principle:

Principle #5Merging (Combining)

3Adaptability or versatility

If more components are mounted to support doubled signal paths, then the modulation functionality is improved, but the relay substrate and module size are increased

Engineering Contradiction:

Improvemodulation functionalityVSAvoidmodule size

Core Design Contradiction:

Adaptability or versatilityVSLength of stationary object

Solution Approach 1:

The electrode wiring configuration uses asymmetric bidirectional groups extending in opposite directions rather than symmetric arrangements. This asymmetric layout optimizes the distribution of components across the relay substrate, allowing compact integration of doubled signal paths without proportionally increasing the overall module length

Inventive Principle:

Principle #4Asymmetry

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 design effectively reduces the size of the optical module by optimizing the layout of electrodes and components, maintaining high-frequency characteristics while minimizing the module's dimensions.

Implementation Method 1

electrodes which cause electronic signals to be applied to the optical waveguide

Methodology Applied

Scientific EffectElectro-optic effect: Electro-Optic Effects

Implementation Method 2

one branched wiring portion has a capacitor and a termination resistor

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS9231728B2Optical module and optical transmitter

Publication Date: 2016.01.05 FUJITSU OPTICAL COMPONENTS LTD

AI summary

An optical module includes a waveguide substrate having an optical waveguide and electrodes that apply electronic signals to the optical waveguide; a relay substrate disposed adjacently to the waveguide substrate; and a termination substrate disposed sandwiching the waveguide substrate with the relay substrate. The electrodes respectively have a first wiring portion connected from the relay substrate through the waveguide substrate to the termination substrate and a second wiring portion extending from the first wiring portion and branching on the termination substrate. In the second wiring portion, one branched wiring portion has a capacitor and a termination resistor, and another branched wiring portion extends through a bias resistor to a DC electrode on the relay substrate. The second wiring portion is divided into a first group extending in a first direction along the optical waveguide and a second group extending in a direction opposite to the first direction.