InP Ring Laser Electro-Refractive Tuning Without Linewidth Broadening

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Solution Overview

Problem

Existing tuneable lasers face challenges in achieving broad frequency tuning without significantly broadening the intrinsic linewidth of the lasing mode, particularly in applications requiring narrow linewidths like high-speed communications and spectroscopy.

Innovation Solution

A monolithically integrated InP tuneable ring laser with a ring cavity comprising ring resonators and a phase modulator configured as PIN diodes, tuned by applying a reverse bias voltage, which utilizes electro-refractive effects to maintain linewidth stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If current injection tuning is used to achieve broad frequency tuning, then the tuning range is improved, but the intrinsic linewidth is significantly broadened

Engineering Contradiction:

Improvetuning rangeVSAvoidlinewidth

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent replaces current injection tuning with electro-refractive tuning using reverse-biased PIN diodes. This substitution eliminates the linewidth broadening mechanism inherent in current injection while maintaining broad tuning capability through voltage-controlled refractive index changes in the InP waveguide.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the tuning mechanism from current-based to voltage-based, utilizing the electro-optic effect in reverse-biased PIN diodes. This parameter change allows frequency tuning through refractive index modulation without the harmful linewidth broadening effects of current injection.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If thermal tuning is used to achieve frequency tuning, then the tuning range is improved, but power consumption increases and heat dissipation occurs

Engineering Contradiction:

Improvetuning rangeVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent substitutes thermal tuning with electro-refractive tuning using reverse-biased PIN diodes. This replacement eliminates the need for thermal energy input, dramatically reducing power consumption and heat dissipation while maintaining broad frequency tuning capability through electrical field control.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent transitions from thermal control to electrical field control for frequency tuning. By using reverse-biased PIN diodes, the system achieves tuning through voltage-controlled refractive index changes rather than temperature changes, resulting in minimal power consumption and no heat dissipation.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If forward bias is used for tuning, then the tuning mechanism is simple, but power consumption increases and heat dissipation occurs

Engineering Contradiction:

Improvetuning simplicityVSAvoidheat dissipation

Core Design Contradiction:

Ease of operationVSLoss of energy

Solution Approach 1:

The patent inverts the conventional forward-bias approach by using reverse-biased PIN diodes for tuning. This inversion maintains operational simplicity while eliminating the energy loss and heat dissipation associated with forward bias, as reverse bias operates in the depletion region without significant current flow.

Inventive Principle:

Principle #13The other way round (Inversion)

4Reliability

If bulk lithium niobite modulator is used for PDH locking, then the locking capability is achieved, but the bandwidth is limited to 5 MHz

Engineering Contradiction:

Improvelocking capabilityVSAvoidbandwidth

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The patent changes the material and operational parameters by using InP-based reverse-biased PIN diodes instead of bulk lithium niobite. This parameter change enables higher bandwidth operation while maintaining PDH locking capability, leveraging the faster response characteristics of the semiconductor structure.

Inventive Principle:

Principle #35Parameter changes

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

The laser achieves tunability over a broad frequency band without disturbing the intrinsic linewidth, offering low power consumption and fast tuning, suitable for applications like telecommunications with reduced heat dissipation and propagation losses.

Implementation Method 1

a cross section of the waveguides of the at least one ring resonator and the phase modulator is configured as PIN diodes and act as an electro-refractive modulator such that the tuneable ring laser is tuneable by applying a reverse bias voltage

Methodology Applied

Scientific EffectElectro-refractive effect: Electro-Optic Effects

Data Source

PatentUS20250253619A1Monolithically integrated inp electro-optically tuneable ring laser, a laser device as well as a corresponding method

Publication Date: 2025.08.07 SMART PHOTONICS HLDG BV

AI summary

A tuneable ring laser having a ring cavity, wherein the ring cavity comprises at least one ring resonator having a waveguide for guiding waves, a phase modulator having a waveguide for guiding waves, one or more power couplers for coupling the waves in, and out of, the at least one ring resonator, wherein a cross section of the waveguides of the at least one ring resonator and the phase modulator is configured as PIN diodes and act as an electro-refractive modulator such that the tuneable ring laser is tuneable by applying a reverse bias voltage.