Photoreceiver Frequency Peak for ODB Signal OSNR

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current DWDM-ODB transmission systems face challenges in achieving optimized sensitivity performance due to high bit-rate to optical signal bandwidth ratios, leading to suboptimal optical signal-to-noise ratios (OSNR) and increased noise interference.

Innovation Solution

The implementation of a photoreceiver with a filter providing a frequency peak in the spectral range between 30% and 70% of the predefined ODB-transmission bit-rate, utilizing a Mach-Zehnder-Interferometer filter and adaptive inverse filtering to compensate for optical filter rolloff, resulting in improved OSNR sensitivity and reduced intersymbol interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If severe optical filtering is performed to increase bit-rate to optical bandwidth ratio, then transmission capacity is improved, but optical signal-to-noise ratio deteriorates

Engineering Contradiction:

Improvetransmission capacityVSAvoidoptical signal-to-noise ratio

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent changes the frequency response parameters of the photoreceiver by introducing a peaked response with specific bandwidth and peak frequency (between 30%-70% of bit rate), rather than using a conventional flat or low-pass response. This parameter optimization allows the system to maintain high transmission capacity while improving OSNR sensitivity by 3-5 dB through enhanced signal detection at the peak frequency.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If optical filter bandwidth is reduced to increase bit-rate to bandwidth ratio, then spectral efficiency is improved, but signal bandwidth is reduced leading to increased noise interference

Engineering Contradiction:

Improvespectral efficiencyVSAvoidnoise interference

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by creating a concentrated frequency peak in the photoreceiver's frequency response at a specific location (between 30%-70% of the bit rate). This localized enhancement of the frequency response at the peak frequency allows the system to extract maximum signal energy from the limited optical bandwidth while rejecting out-of-band noise, thereby improving OSNR without sacrificing spectral efficiency.

Inventive Principle:

Principle #3Local quality

3Reliability

If conventional photoreceiver frequency response is used, then device complexity is low, but OSNR sensitivity is suboptimal

Engineering Contradiction:

ImproveOSNR sensitivityVSAvoidphotoreceiver design

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent optimizes the frequency response parameters of the photoreceiver by introducing a peaked response with specific characteristics (peak frequency between 30%-70% of bit rate, bandwidth optimized for the application). This parameter optimization can be achieved through standard photodetector designs with appropriate filtering, providing 3-5 dB OSNR sensitivity improvement without requiring fundamentally new or overly complex device architectures.

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

This approach achieves unsurpassed OSNR values, with a 12 dB sensitivity at 44.6 Gb/s, and maintains high sensitivity performance even at low OSNR conditions, while minimizing the impact of thermal noise and intersymbol interference.

Implementation Method 1

a Mach-Zehnder-Interferometer, MZI, filter may be employed

Methodology Applied

Scientific EffectInterference: Interference

Implementation Method 2

the optical ODB signal may be split into a first signal portion and a second signal portion, wherein the first signal portion is filtered by a Mach-Zehnder-Interferometer, MZI, filter

Methodology Applied

Scientific EffectOptical filtering: Filter (optical)

Implementation Method 3

The added signal portions at each exit port may be detected with the respective photodiode

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 4

The anode-terminals of both photodiodes may be connected with each other and with the input terminal of a transimpedance amplifier. As such, the transimpedance amplifier may amplify the added signals

Methodology Applied

Scientific EffectElectrical amplification:

Data Source

PatentUS9490908B2Method and system for receiving an optical-duo-binary signal

Publication Date: 2016.11.08 II VI DELAWARE INC

AI summary

The invention inter alia relates to a method of receiving an optical-duo-binary, ODB, signal (S), which has a predefined ODB-transmission bit-rate (B), using a photoreceiver, said method comprising the step of filtering the ODB signal using a filter (10) which provides a frequency peak in the photoreceiver's frequency response located in the spectral range between 30% and 70% of the predefined ODB-transmission bit-rate.