OCAM1

Question 1

Define Optical Communications

Answer 1

Transmission of information by using light over a given distance

Question 2

Properties of OC (4)

Answer 2

1) Light path is defined by a transmission medium
2) Light is propagated (travel) down the medium by a light source
3) Light is collected and interpreted by a receiver
4) The light signal must account for the properties of light

Question 3

Applications of OC (5)

Answer 3

1) OC transport networks
2) Cloud computing
3) Carrier ethernet support
4) Data centres
5) Medical centres

Question 4

What are the key OC technology development for OC Transport Networks? (4)

Answer 4

1) Optical Transmitters
2) Transmission mediums
3) High sensitivity, low noise photo detectors
4) Advanced modulation schemes

Question 5

Key properties of optical transmitters

Answer 5

1) Continuous-wave lasers are needed for their steady stream

2) Room temperature lasers allow lasers to work at RT and removes need for heat dissipating equipment

Question 6

What is the transmission medium we use in OC?

Answer 6

Low loss optical fiber

Question 7

What do photo detectors do?

Answer 7

They collect (receive) light and covert it to an electrical current

Question 8

What is the purpose of advanced modulation schemes?

Answer 8

They allow for more data to be imposed on the transmission medium

Question 9

What the advantages of using OC? (5)

Answer 9

1) Greater distances supported
2) Higher service capacity
3) Greater service flexibility
4) Lower cost
5) Increased security

Question 10

How does OC support greater distances? (2)

Answer 10

1) Low loss optical fibre as the carrier signal

2) Ability to support optical amplification

Question 11

How does OC support greater capacity? (2)

Answer 11

1) Higher bit rate support

2) Multiple optical signal support when using Wave Division Multiplexing (WDM)

Question 12

How does OC achieve service flexibility?

Answer 12

By supporting:

1) Sub-lambda electrical client multiplexing using an optical transport protocol
2) Lambda-based services with the use of WDM channels

Question 13

Why is OC cheaper to use than copper based technologies?

Answer 13

1) A single infrastructure can support all client traffic types
2) Ability to reduce and/or eliminate to need to regenerate
3) Optical amplification allows for distance extension

Question 14

Types of OC Transport Networks

Answer 14

1) Provider - provider
2) Provider - enterprise
3) Enterprise - enterprise

Question 15

Define OC Provider

Answer 15

An OC transport network operator that carries data traffic for the purpose of revenue generation or to support operational goals. E.g. Multi-service Operator (MSO), Internet Content Provider (ICP), the government

Question 16

Define an OC Enterprise

Answer 16

A business entity that does not derive its main revenue stream from carrying another operational entity’s traffic over an OC network. The network is used to support business goals of the lone organisation. E.g. Health Care Network; Utility company

Question 17

Characteristics of OC Transport Network

Answer 17

1) Higher bandwidth
2) Higher reliability
3) Standardised manageability across operational entities
4) Photonic networks that span data centres; clouds; Metro area networks (MANSs); Wide Area Networks (WANs) and long haul distances (including submarine)
5) Transport voice, video and data within and across geographical locations

Question 18

Deployment types of OC Transport Networks

Answer 18

1) Metro Area Network (MAN)
2) Long haul terrestrial
3) Submarine

Question 19

What is a Metro Area Network?

Answer 19

1) Medium distance OC network that connects business and sites in a geographical location like a city
2) Used to collect traffic access to common points for service connectivity

Question 20

What is a long haul terrestrial network?

Answer 20

The core of OC network that connects different geographical locations, while provide aggregation for MANs. There are 3 types:

1) Long haul (600-1000km)
2) Extended long haul ( 1000-2000km)
3) Ultra long haul (>2000km)

Question 21

What is a submarine network?

Answer 21

An ultra long haul WAN network that connects different geographical locations that are separated by large bodies of water. Can be used where there are sea depths of up to 8000m with spans reaching thousands of KMs

Question 22

Protocols used in OC Networks

Answer 22

1) Synchronous Optical Network (SONET)
2) Synchronous Digital Hierarchy (SDH)
3) Optical Transport Network (OTN)