Laser Slope Efficiency Calculation in Optical Transceiver Modules

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing optical transmitters face challenges in dynamically measuring and compensating for laser slope efficiency due to temperature fluctuations and operational variability over the lifetime of the laser, leading to deviations from acceptable parameter ranges, which existing solutions like temperature-sensitive analog components and pre-set compensation tables are unable to effectively address.

Innovation Solution

A system and method that involves sensors to measure bias current, modulation current, and transmit power, with a processor calculating the slope efficiency and adjusting the modulation current to maintain optimal performance, allowing for dynamic compensation and calibration of the laser.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If pre-set compensation tables based on digital measurement are used, then laser parameter compensation is achieved, but manufacturing time and cost increase due to calibration requirements

Engineering Contradiction:

Improvelaser parameter compensationVSAvoidmanufacturing time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system performs self-calibration by automatically measuring its own laser characteristics and generating compensation tables without external intervention. The calibration process is automated through the controller that measures laser parameters at different temperatures and currents, eliminating the need for manual calibration during manufacturing.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system performs preliminary calibration measurements during manufacturing to build compensation tables in advance. These tables are stored in memory and used during operation to quickly compensate for temperature and aging effects without requiring real-time complex calculations.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If pre-set compensation tables are used, then laser parameter compensation is provided, but adaptability to individual laser variations is limited

Engineering Contradiction:

Improvelaser parameter compensationVSAvoiddynamic laser modification

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system dynamically adjusts laser operating parameters based on real-time temperature measurements and stored compensation characteristics. The controller continuously monitors temperature and selects appropriate compensation values from lookup tables, enabling adaptive response to changing conditions throughout the laser's operational life.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes operational parameters (current, power) based on measured temperature and laser characteristics. Compensation tables store relationships between temperature, current, and optimal operating parameters, allowing the system to adapt to individual laser variations and aging effects.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If temperature-sensitive analog components are used, then real-time laser current adjustment is enabled, but device complexity increases

Engineering Contradiction:

Improvereal-time laser current adjustmentVSAvoidanalog components

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The system replaces complex analog temperature-sensitive components with a digital control approach. Instead of using analog circuits to automatically adjust current based on temperature, the system uses a controller that digitally processes temperature measurements and selects compensation values from stored tables, simplifying the hardware while maintaining real-time adjustment capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The controller acts as an intermediary between temperature sensing and laser current control. Rather than directly coupling analog temperature sensors to current adjustment circuits, the controller mediates by reading temperature, consulting stored compensation data, and commanding appropriate current adjustments, thereby simplifying the overall system architecture.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS7639952B2Calculation of laser slope efficiency in an optical transceiver module

Publication Date: 2009.12.29 II VI DELAWARE INC

AI summary

Systems and methods are provided for determining and compensating for the laser slope efficiency of a light source positioned in an optical transmitter in order to properly set a modulation current for the light source. In one embodiment, a method for setting a modulation current for the laser of an optical transmitter is disclosed, wherein data relating to the laser transmit power and laser bias current at a plurality of laser bias current levels are sensed. A processor is then employed to calculate a slope efficiency of the laser using the data. The processor then determines a desired modulation current for the laser using the slope efficiency. Then if needed, the modulation current of the laser is modified to match the desired modulation current.