Tunable DWDM Transceiver Wavelength Stabilization

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Solution Overview

Problem

Current DWDM transceivers, particularly those with 50 GHz channel spacing, face challenges in maintaining wavelength stability due to aging thermistors and temperature gradients, leading to optical crosstalk and increased costs from the need for wavelength lockers, which are not commercially feasible for hot-pluggable transceivers.

Innovation Solution

A tunable DWDM transceiver system that includes a microcontroller, wavelength meter, and temperature control circuit to compare preset and actual wavelengths, forming a feedback loop to calibrate and stabilize the emission wavelength, using an accelerated burn-in EML laser to minimize deviations and enable operation at both 50 GHz and 100 GHz channel spacings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a wavelength locker is used to maintain wavelength stability in 50 GHz DWDM transceivers, then optical crosstalk is reduced, but device complexity and cost increase

Engineering Contradiction:

Improvewavelength stabilityVSAvoidlaser package size

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the wavelength stabilization function from a separate wavelength locker component and integrates it into the existing temperature control system. The temperature control circuit is modified to receive wavelength information from a meter and adjust the laser temperature accordingly, eliminating the need for a dedicated wavelength locker and reducing device complexity while maintaining wavelength stability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the wavelength control function with the temperature control function. The temperature control circuit serves dual purposes: maintaining thermal stability and adjusting wavelength through temperature modulation. This combination reduces the number of components and simplifies the overall system architecture

Inventive Principle:

Principle #5Merging (Combining)

2Temperature

If thermistor temperature monitoring is used for wavelength control, then temperature stability is improved, but manufacturing precision deteriorates due to thermistor aging

Engineering Contradiction:

Improvetemperature stabilityVSAvoidwavelength accuracy

Core Design Contradiction:

TemperatureVSManufacturing precision

Solution Approach 1:

The patent implements a feedback mechanism where a wavelength meter continuously measures the actual emission wavelength and provides this information to the temperature control circuit. The system dynamically adjusts the laser temperature based on real-time wavelength measurements, compensating for thermistor aging and maintaining wavelength accuracy throughout the device lifecycle

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system performs preliminary wavelength measurement and adjustment during the startup and calibration phases. The wavelength meter characterizes the laser's wavelength-temperature relationship, and the system pre-configures temperature control parameters to account for expected drift, reducing the need for frequent recalibration

Inventive Principle:

Principle #10Preliminary action

3Reliability

If cooled EML lasers are used for 50 GHz channel spacing, then wavelength stability is improved, but device complexity and cost increase

Engineering Contradiction:

Improvewavelength stabilityVSAvoidtransceiver structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent designs a universal transceiver architecture that can operate at both 50 GHz and 100 GHz channel spacings. The temperature control circuit and wavelength measurement system are configured to support multiple channel spacing modes, allowing a single device design to serve multiple applications without requiring separate optimized designs for each channel spacing

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 solution provides a cost-effective, stable DWDM transceiver capable of operating at both 50 GHz and 100 GHz channel spacings, reducing optical crosstalk and maintaining compliance with wavelength stability specifications, while allowing for switching between channel spacings.

Implementation Method 1

a temperature control circuit to stabilize the emission wavelength of the EML laser

Methodology Applied

Scientific EffectTemperature control:

Implementation Method 2

Methodology Applied

Scientific EffectFeedback control: Feedback

Data Source

PatentUS8929748B2Tunable dense wavelength division multiplexing transceiver, circuits and devices therefor, and methods for making and using such transceivers, circuits and devices

Publication Date: 2015.01.06 SOURCE PHOTONICS INC

AI summary

The disclosure relates to a tunable 50 GHz and 100 GHz channel spacing DWDM transceiver, and methods of making and using the same. The transceiver comprises an electro-absorption modulation laser (EML), a system board configured to compare a preset wavelength with an actual emission wavelength of the EML, a microcontroller and one or more associated registers configured to communicate with the system board, a temperature controlling circuit configured to stabilize the actual emission wavelength of the EML; and a wavelength meter connected to the output of the EML and having an output connected to the system board. The system board may be configured to provide a feedback loop from the EML to the microcontroller. The transceiver, suitable for 50 GHz channel spacing standards, can be made from existing standard transceivers and can switch between 50 GHz and 100 GHz channel spacing modes.