Full report on light peak technology

0

INDEX

INTRODUCTION……………………………………..1

LIGHT PEAK TECHNOLOGY: FEATURES ……….2

TODAYS CHALLENGES……………………………4

LIGHT PEAK VS USB 3.0…………………………...6

COMPONENT OVERVIEW…………………………7

FUNDAMENTALS OF OPTICAL COMPONENTS...8

OPTICAL FIBER

LIGHT SOURCES

LIGHT DETECTORS

PACKAGING: ASEEMBLY AND TRANSCEIVERS

VCSEL

OPTICAL MODULE…………………………………12

LIGHT PEAK TECHNOLOGY OVERVIEW……….14

PROTOCOL ARCHITECTURE

LIGHT PEAK CONTROLLER

LIGHT PEAK PLATFORM

DIRECT NETWORK OF SERVERS

DATA TRANSFER SPEED COMPARISION………19

BRINGING OPTICAL TO MAINSTREAM………...20

ADVANTAGES……………………………………...21

DEVELOPMENT STATUS………………………….22

CONCLUSION……………………………………….23

REFERENCES………………………………………..24

1

INTRODUCTION

The present era is the era of connectivity. Think of any sort of information, and it can be

transferred to us within question of a little time; be it audio information, video information or

any other form of data.

Now talking about transferring data between our computer and the other peripherals, the first and

foremost standard comes to our mind is Universal Serial Bus (USB). It is a medium speed serial

data addressable bus system which carry large amount of data to a relatively short distance (up to

5m).The present version USB 3.0 promises to provide theoretical speed of up to 5Gbps.

But Intel has unveiled a new interoperable standard called LIGHT PEAK which can transfer

data between computers and the peripherals at the speed of 10Gbps in both the directions with

maximum range of 100m (much higher than USB or any other standard) and has potential to

scale its speed high up to 100Gbps in near future.

Light Peak is the code name for a new high-speed optical cable technology designed to connect

electronic devices to each other.

Light Peak is basically an optical cable interface designed to connect devices in peripheral bus. It

is being developed as a single universal replacement for the current buses such as SCSI, SATA,

USB, FireWire, PCIExpress, and HDMI etc in an attempt to reduce the proliferation of ports on

computers.

Fiber-optic cabling is not new, but Intel executives believe Light Peak will make it cheap enough

and small enough to be incorporated into consumer electronics at a price point that consumers

and manufacturers will accept.

Thus with light peak, the bandwidth would tremendously increase, multiple protocols could be

run over single longer and thinner cable.

The prototype system featured two motherboard controllers that both supported two bidirectional

buses at the same time, wired to four external connectors. Each pair of optical cables from the

controllers is led to a connector, where power is added through separate wiring. The physical

connector used on the prototype system looks similar to the existing USB or FireWire

connectors.

Intel has stated that Light Peak has the performance to drive everything from storage to displays

to networking, and it can maintain those speeds over 100 meter runs.

2

LIGHT PEAK TECHNOLOGY: FEATURES

“At some point the industry is going to have to transition. I think the next transition is going to

be to optics.”

- Jeff Ravencraft, USB-IF president and chairman

Optical networking technologies have been over the last two decades reshaping the e ntire

telecom infrastructure networks around the world and as network bandwidth requirements

increase, optical communication and networking technologies have been moving from their

telecom origin into the enterprise and Light Peak is one of its successful outcome.

It is basically a new high-speed optical cable technology designed to connect electronic devices

to each other. It also support multiple protocols simultaneously with the bidirectional speed of

about 10Gbps (can scale up to about 100Gbps). In comparison to other bus standards like SATA

and HDMI, it is much faster, smaller, longer ranged, and more flexible in terms of protocol

support.

Thus it basically provides:

Standard low cost high bandwidth optical-based interconnect.

Supports multiple existing I/O protocols and smooth transition between them.

Supports wide range of devices (handhelds, PCs, workstations etc.)

Connect to more devices with the same cable, or to combo devices such as docking

stations.

Smaller connectors.

Longer (up to 100m on single cable), thinner and economical.

Light peak consist of a controller chip and optical module that would be included in platform to

support this technology. The optical module performs the task of conversion of electricity to

light conversion and vice versa, using miniature lasers and photo detectors. This transceiver can

send two channels of information over an optical cable, necessary, since pc needs at least two

ports. The controller chip provides protocol switching to support multiple protocols over single

cable.

The Light Peak cable contains a pair of optical fibers that are used for upstream and downstream

traffic to provide speed of about 10Gbps in both the directions.

The prototype system featured two motherboard controllers that both supported two bidirectional

buses at the same time, wired to four external connectors. Each pair of optical cables from the

controllers is led to a connector, where power is added through separate wiring.

3

It was developed as a way to reduce proliferation of number of ports on the modern computer.

Earlier USB was developed for the same purpose and performed very well in this direction but

increased bandwidth demand and high performance has led to development of new more

efficient technologies.

Combining the high bandwidth of optical fiber with Intel’s practice to multiplex multiple

protocols over a single fiber, optical technology may change the landscape of IO system design

in the future. It’s possible that most of the legacy IO protocols can be tunneled by optical-

capable protocols, so some of the legacy IO interfaces can be converged to one single optical

interface, significantly simplifying the form factor design of computers. This change in IO

system will definitely affect the design of systems.

Fig. 1: Abstract model of the optical-enabled system (Arrow shows that we are looking at the system from IO to

processor)

There are four main components in this figure, the IO devices, the IO controller which connects

to the IO devices through optical fiber, the processing unit and the interconnection between the

IO controller and the processing unit, whatever it can be implemented as.

Mobile and handheld devices are two fast growing market segments which attract interests from

processor vendors. For mobile and handheld devices, user interface and IO are two important

factors besides computing power that affect end users’ purchase decision. Taking power into

account, it’s possible that more carefully tuned IO workload offloading engines will be

integrated into the IO controller, saving the power to move the data from IO a long way to the

system memory. It makes no sense to have a high throughput IO system with insufficient

processing power or overloaded interconnections between IO system and the processor.

The ultimate goal of system architects is to make a balanced and efficient system, on both power

and cost grounds.

4

TODAYS CHALLENGES

In the coming future, people would be using more and more electrical deices such as HD

devices, MIDs and many more and user experience would depend on the huge volume of data

capturing, transfer, storage, and reconstruction. But existing electrical cable technology is

approaching the practical limit for higher bandwidth and longer distance, due to the signal

degradation caused by electro-magnetic interference (EMI) and signal integrity issues.

Higher bandwidth can be achieved by sending the signals down with more wires, but apparently

this approach increases cost, power and difficulty of PCB layout, which explains why serial links

such as SATA, SAS, and USB are becoming the mainstream.

However optical communications do not create EMI by using photonics rather than electrons,

thus allowing higher bandwidth and longer distances. Besides, optical technology also allows for

small form factors and longer, thinner cables.

Electrons v/s Photons

The physics has a kind of inevitability about it. Electrons travel through copper more slowly than

light through fiber. The USB connectors on the smaller devices like mobile phones have to use

mini-USB or micro-USB to save on the space taken up by the wiring and electricity through wire

creates electric field interference, but light do not create EMI since it rely over photonics. Optical

connecters can carry extremely narrow beams of light and fiber can be thinner because more

streams can pass through glass or plastic passages. Each fiber is only 125 microns wide, the

width of a human hair.

In the present scenario, the devices are getting smaller, thinner, and lighter but present

connecting standards seems to hinder in their performance being to thicker and stiffer. So

vendors turn over to new technologies providing much better performance and Light Peak seems

to be a providing a good solution.

Different protocols demands for different connectors leading to too many connectors and cables.

But in Light Peak there is the Light Peak protocol and the native protocols such as PCI Express,

DisplayPort, USB or whatever might be running on it. The native protocols run basically on top

of the Light Peak protocol. But the Light Peak protocol defines the speed. The protocol is

running at 10 gigabits per second. So, if the native protocols that are running on top of it are also

running at 10 gigabits per second, or something close to that, then the effective bandwidth for a

device on the other end would be equivalent to that 10Gbps.

5

Thus, it can be said that presently we demand for the devices and technologies that:

Provides much higher bandwidth

Provides more flexible designs, thinner form factor and new and better usage models.

Much simpler and easier in terms of connectivity.

It’s possible that most of the legacy IO protocols can be tunneled by optical-capable protocols, so

some of the legacy IO interfaces can be converged to one single optical interface, significantly

simplifying the form factor design of computers. This change in IO system will definitely affect

the design of systems. It makes no sense to have a high throughput IO system with insufficient

processing power or overloaded interconnections between IO system and the processor.

Ultimately the main aim is to built an efficient and balanced system.

Thus Light Peak seems to be providing a good solution to the problems existing with the copper

connectors and provides a good platform for the high performance system.

6

LIGHT PEAK V/S USB 3.0

USB 3.0

It is an electrical cable technology which transmits data using electricity which put

limitation on speed and length.

It consists of 9 copper wires for transfer of data between the PC and the peripherals.

Theoretically it can provide maximum speed of 5Gbps which on practical grounds get

restricted to about 3Gbps.

It supports only USB protocol.

The maximum allowable cable length for USB 3.0 is only about nine meters

LIGHT PEAK

It is an optical cable technology which relies over light to transmit data thus providing

much better speed and length.

It consists of 4 optical fibers for both upstream and downstream traffic simultaneously.

Initial proposed speed for Light Peak (LPK) [10] starts at 10Gbps and has future potential

to scale up to 100Gbps. With this speed Blu-Ray movie can be transferred in less than 30

seconds (or in less than 3 seconds with 100Gbps).

It is a Universal connector supporting multiple existing protocols.

The maximum allowable cable length is about 100 meters and can be even extended

more.

7

COMPONENTS OVERVIEW

Light Peak consists of a controller chip and an optical module that would be included in

platforms supporting this technology. The optical module performs the conversion from

electricity to light and vice versa, using miniature lasers (VCSELs) and photo detectors. Intel is

planning to supply the controller chip, and is working with other component manufacturers to

deliver all the Light Peak components. The main components are:

Fiber optics

Optical module

Controller chip

FIG 4: Prototype view of components of light peak controller

These are the fundamentally required components for a basic light peak connector. The

description for each would be given in forgoing discussion.

8

FUNDAMENTALS OF OPTICAL COMPONENTS

A basic optical communication link consists of three key building blocks: optical fiber, light

sources, and light detectors.

OPTICAL FIBER:

The silica-based optical fiber structure consists of a cladding layer with a lower refractive index

than the fiber core it surrounds. This refractive index difference causes a total internal reflection,

which guides the propagating light through the fiber core with an attenuation less than 20 dB/km,

necessary threshold to make fiber optics a viable transmission technology. For

telecommunications, the fiber is glass based with two main categories: SMF (Single-mode fiber)

and MMF (Multi-mode fiber)

SMFs typically have a core diameter of about 9 μm, while MMFs typically have a core diameter

ranging from 50 to 62.5 μm.

Optical fibers have two primary types of impairment: optical attenuation and dispersion

The fiber optical attenuation, which is mainly caused by absorption and the intrinsic Rayleigh

scattering, is a wavelength dependent loss with optical losses as low as 0.2 dB/km around 1550

nm for conventional SMF (SMF-28).

The optical fiber is a dispersive waveguide. There are three primary types of fiber dispersions:

Modal dispersion:

It depends on both core diameter and transmitted wavelength. For a single-mode

transmission, the step-index fiber core diameter (D) must satisfy the following condition:

where λ is the transmitted wavelength and n1 and n2 are the refractive indices of fiber core

and cladding layer, respectively.

Chromatic dispersion:

It is due to the wavelength-dependent refractive index with a zero-dispersion wavelength

occurring at 1310 nm in conventional SMF. When short duration optical pulses are launched

into the fiber, they tend to broaden since different wavelengths propagate at different group

velocities, due to the spectral width of the emitter. Optical transmission systems operating at

rates of 10 Gbps or higher and distances above 40 km are sensitive to this phenomenon.

9

Polarization-mode dispersion:

It is caused by small amounts of asymmetry and stress in the fiber core due to the

manufacturing process and environmental changes such as temperature and strains. This

fiber core asymmetry and stress leads to a polarization-dependent index of refraction and

propagation constant, thus limiting the transmission distance of high speed (≥ 10 Gbps) over

SMF in optical communication systems.

Optical fiber is never bare. The fiber is coated with a thin primary coating to protect the inner

glass fiber from environmental hazards.

Light Peak is based on Laser-optimized Multi-mode fiber (LOMF). By laser optimized it just

means that the fiber was designed to be used with lasers, and in the case of MMF, typically

VCSELs.

The internal diameter of each Light Peak fiber is 62.5 microns (around half the size of a human

hair, but thicker than the fiber used in telecoms). The beam expander moulded into the lens

expands that to 700 microns, so that dust — usually around 100 microns — may interrupt the

beam partially but the connection will still work. The beam expander also compensates for

distortion or movement in the connector after been used for a while.

Light Peak fiber has a 3-micron coating to prevent cracking, it can be bend to a radius of 3mm

and it won't break.

It is mixed with copper wires for power and fiber optic cables for data. The commercial version

of the connector has not been released to the public, but it would be possible to create a light

peak port that is backwards compatible with USB. The fiber optic connection could be deep in

the connector so it would be undamaged by a standard USB cable. Electrical connections could

be provided for a standard USB 1.1/2.0 cable so that the connector could provide both fiber optic

and electrical connections.

LIGHT SOURCE:

The light source is often the most costly element of an optical communication system. It has the

following key characteristics: (a) peak wavelength, at which the source emits most of its optical

power, (b) spectral width, (c) output power, (d) threshold current, (e) light vs. Current linearity,

(f) and a spectral emission pattern.

There are two types of light sources in widespread use: the Laser Diode (LD) and the Light

Emitting Diode (LEDs).

10

Both LEDs and LDs use the same key materials: Gallium Aluminum Arsenide (GaAIAs) for

short-wavelength devices and Indium Gallium Arsenide Phosphide (InGaAsP) for long-

wavelength devices.

Semiconductor laser diode structures can be divided into the so-called edge-emitters, such as

Fabry Perot (FP) and Distributed Feedback (DFB) lasers and vertical-emitters, such as Vertical

Surface Emitting Lasers (VCSELs).

For Light Peak optical modules, VCSELs are used as light source.

In optical networks, binary digital modulation is typically used, namely on (light on) and off (no

light) to transmit data. These semiconductor laser devices generate output light intensity which is

proportional to the current applied to them, therefore making them suitable for modulation to

transmit data.

Modulation schemes can be divided into two main categories: a direct and an external

modulation.

In a direct modulation scheme, modulation of the input current to the semiconductor laser

directly modulates its output optical signal since the output optical power is proportional to the

drive current. In an external modulation scheme, the semiconductor laser is operating in a

Continuous-Wave (CW) mode at a fixed operating point. An electrical drive signal is applied to

an optical modulator, which is external to the laser. Consequently, the applied drive signal

modulates the laser output light on and off without affecting the laser operation.

The direct modulation of a laser diode has several limitations, including limited propagation

distance due to the interaction between the laser, frequency chirp and fiber dispersion. This is not

an issue for enterprise networks which are short distance and thus lasers can be modulated

directly.

LIGHT DETECTORS:

Light detectors convert an optical signal to an electrical signal. It operates on the principle of the

p-n junction.

There are two main categories of photo detectors: a p- i-n (positive- intrinsic-negative)

photodiode and an Avalanche Photodiode (APD), which are typically made of InGaAs or

germanium.

The key parameters for photodiodes are: (a) capacitance, (b) response time, (c) linearity, (d)

noise, and (e) responsitivity.

Amplifier is needed to amplify the electric current to a few mA.

Light Peak modules uses pin photodiodes as light detectors since these are more economical.

11

PACKAGING: OPTICAL SUBASSEMBLY AND TRANSEIVERS

To enable the reliable operation of laser diodes and photodiodes devices, an optical package is

required. There are many discrete optical and electronic components, which are based on

different technologies that must be optically aligned and integrated within the optical package.

Optical packaging of laser diodes and photodiodes is the primary cost driver. These package s are

called as Optical Sub-Assemblies (OSAs).

Tunable 10 Gbps lasers use a similar butterfly optical package. The butterfly package design

uses a coaxial interface for passing broadband data into the package, which requires the use of a

coaxial interface to the host Printed Circuit Board (PCB). To operate with high- performance,

uncooled designs must be implemented with more advanced control systems that can adjust the

laser and driver parameters over temperature.

TO-can-based designs are now maturing to support high performance 10 Gbps optical links.

These designs being produced in high volumes will further reduce the cost of optical modules.

OPTICAL TRANSEIVERS:

The optical transmitter and receiver modules are usually packaged into a single package called

an optical transceiver.

There are several form factors for this optical transceiver depending on their operating speed and

applications.

Fig. 5: PCB of transceiver

Above figure shows an example of the printed circuit board of a transceiver. The industry

worked on a Multi-Source Agreement (MSA) document to define the properties of the optical

transceivers in terms of their mechanical, optical, and electrical specifications. Optical

transponders operating at 10 Gb/s, based on MSA, have been in the market s ince circa 2000,

beginning with the 300-pin MSA, followed by XENPAK, XPAK, X2, and XFP.

12

OPTICAL MODULE

Light Peak is based on 10G 850nm VCSEL and PIN-diode arrays with LOMF (Laser-optimized

Multi-mode Fiber) and a new optical interface connector yet to be determined.

The optical module does the function of converting optical signals into electrical signals and vice

versa. This module contains an array of VCSEL (vertical cavity surface emitting laser).

FIG 6: Schematic diagram of Optical module

VCSEL (Vertical-Cavity Surface- Emitting Laser Diodes):

FIG 7: Simplified schematic for VCSEL without substrate, electrode for pumping, structure for current confinement

etc.

VCSELs are semiconductor lasers, more specifically laser diodes with a monolithic laser

resonator, where the emitted light leaves the device in a direction perpendicular to the chip

surface. The laser resonator consists of two distributed Bragg reflector (DBR) mirrors parallel to

the wafer surface with an active region consisting of one or more quantum wells for the laser

light generation in between. The planar DBR-mirrors consist of layers with alternating high and

low refractive indices. Each layer has a thickness of a quarter of the laser wavelength in the

material, yielding intensity reflectivities above 99%.

VCSELs has low-cost potential because the devices are completed and tested at the wafer level

for material quality and processing purposes and a matrix VCSEL is capable of delivering high

power( up to few watts).

13

VCSELs have low threshold current value, low temperature sensitivity, high transmission speed,

high fiber coupling efficiency and circular and low divergence output beam as compared to edge-

emitters.

VCSELs for wavelengths from 650 nm to 1300 nm are typically based on gallium arsenide

(GaAs) wafers with DBRs formed from GaAs and aluminium gallium arsenide (AlxGa(1-x)As).

The current is confined in an oxide VCSEL by oxidizing the material around the aperture of the

VCSEL. As a result in the oxide VCSEL, the current path is confined by the ion implant and the

oxide aperture.

The wavelength of VCSELs may be tuned, within the gain band of the active region, by

adjusting the thickness of the reflector layers.

In the present demonstrated Light Peak technology, architecture of optical interconnects is built

up on the bases of four VCSELD and two optical links where thermal effects of both the diodes

and the links are included. Nonlinear relations are correlated to investigate the power-current and

the voltage-current dependences of the four devices. The good performance (high speed) o f

interconnects are deeply and parametrically investigated under wide ranges of the affecting

parameters. The high speed performance is processed through three different effects, namely the

device 3-dB bandwidth, the link dispersion characteristics, and the transmitted bit rate. Eight

combinations are investigated; each possesses its own characteristics. The best architecture is the

one composed of VCSELD that operates at 850 nm and the silica fiber whatever the operating set

of causes. This combination possesses the largest device 3-dB bandwidth, the largest link

bandwidth and the largest transmitted bit rate.

The Light Peak module detects when cables are cut or unplugged and automatically turns off the

laser.

The Light Peak optical module is only12mm by 12mm and drives two optical ports.

A single-chip solution will be in demand for Light Peak as well, but to date Intel has simply

suggested that it will be providing the controller chip and is working with industry partners to

provide other various components.

14

LIGHT PEAK TECHNOLOGY OVERVIEW

Light Peak Technology is an optical cable technology that consists of an optical module

and controller chip which allows multiple protocols to run over the single cable. From the

technical point of view, Intel’s Light Peak Technology can be overviewed as:

Light peak protocol

Light Peak controller

Light peak platforms

Server Network

LIGHT PEAK PROTOCOL ARCHITECTURE:

Efficient transport mechanism:

It uses packet switch multiplexing.

Packetize data to transfer

Multiplex it onto the wire

Packets from different connections share the same link.

Each packet is composed by the payload (the data we want to transmit) and a header. The header

contains information useful for transmission, such as:

• Source (sender’s) address

• Destination (recipient’s) address

• Packet size

• Sequence number

• Error checking information

15

FIG 8: Simplified view of protocol

Light Peak Networks use a similar idea of packet switching.

All the IO devices may have their native protocols but when using Light Peak they all run over

Light Peak protocol. That is they uses their individual protocol for data transfer but their speed is

defined by light peak.

Also it uses Virtual Wire Semantics thus performs high level of isolation between high level

protocols (QoS).

It provides cheap switching and establishes all routing at the setup only.

LIGHT PEAK CONTROLLER:

At the heart of Light Peak is an Intel-designed controller chip that handles the protocols, along

with an optical module that converts electrical signals to photons and vice versa.

Basic implementation unit of Light Peak Controller contains:

A Cross bar switching unit: switches the various protocols from LPK to their respective

protocol adapter.

LPK Ports and Protocol Adapter ports: LPK ports to connect down to PC using any

standard and diverging it their respective protocol through protocol adapter.

Cable and

connectors

Electrical/Optical

PHY

Common Transport LIGHT

PEAK

IO

Pro

toc

ol

IO

Pro

toc

ol

IO

prot

ocol Application

specific

Protocol

16

Adapter

Adapter

LPK

Adapter

FIG 9: LIGHT PEAK CONTROLLER SCHEMATIC

Fig. 10: LPK controller chip

The Host controller is typically multi protocol and has multiple ports with a software interface

unit and is optimized for host side implementation whereas the peripheral controller could be

single port and single protocol-based and is optimized for particular usage.

This is because of this controller chip that different pro tocols get identified and transmitted

correctly. API (Application programming interface) helps to determine the different protocols. It

places the FIS (Flag Identification Symbol) packets in the memory, the controller access these

packets from the memory and send these packets to the destination over the optical link.

The multi-protocol capability the controller implements is an innovative new technology that

will enable new usage models like flexible system designs and thinner form factors, media

creation and connectivity, faster media transfer and cable simplification.

Crossbar

Switch

LPK

LPK

LPK

Adapter

Adapter

Adapter

PROTOCOL

ADAPTER

PORTS

LIGHT PEAK PORTS

17

LIGHT PEAK PLATFORM:

A typical Light Peak platform can be viewed with few of these examples:

FIG 11 Mobile Platform

FIG 12: Entusiast/Workstation

CPU Mem

dGFX

PCH

LPK

Controller

PCIe

Display

PCIe

DMI

CPU

IOH

Mem

dGFX

ICH

LPK

Controller

LPK

Contoller Display

PCIe

PCIe

QPI

DMI PCIe

Display

18

DIRECT NETWORK OF SERVERS:

Goal: Build a high-bandwidth, fault- resilient, low-cost network that can deliver performance

isolation across applications.

Approach:

– Integrate low-radix switches into several platforms.

– Interconnect servers directly using multi- path topologies.

Why Light Peak to be considered as an option?

– Small buffers and tables enable cheaper switching components

– Bandwidth allocation and performance isolation

– Flexible topologies and multi-path enables better resiliency.

SERVER

SERVER

SERVER

SERVER

19

DATA TRANSFER SPEED COMPARISION

How does Light Peak compare to the latest technologies? The slowest is wireless. HDMI version

1.3 and higher will transfer at 10.2 Gbps, while Display Port can go up to 10.8 Gbps. These are

slightly better than Light Peak, but they are mostly designed for video. No one is pushing the

data transfer rates of these protocols.

FIG 13: The chart shows how Light Peak compares to all of these other protocols. At 10 Gbps, it can cover a whole

range of transfer protocols. The magic of Light Peaks is that it can become the cable of choice fo r all these protocols

with no significant loss in transfer speed.

20

BRINGING OPTICAL TO MAINSTREAM

Since Light Peak is developed to meet PC requirements and the telecom ones, thus the Light

Peak optical module can be designed to be lower cost than Telecom optical modules. This is due

to some modification in design considerations:

First Intel relaxed the optical standards required of its components. In the telecom

market, components must meet stringent Telcordia standards, such as a 20-year lifetime.

Obviously, that kind of longevity is not required in the PC market, so Intel lowered its

requirements to a five- to seven-year lifetime.

Requirements for the operating environment also are not as rigorous. Intel lowered

thermal requirements from the Telcordia-specified range of 0° to 85° to a more relaxed 5°

to 65°. Intel had originally intended to specify a range starting at 0° but then realized that

batteries freeze at that temperature, making the operation of the PC a moot point.

The company also relaxed its specification for number of failures per lifetime. I f there is

a failure on a trans-Atlantic cable, it’s a big deal. But the potential failure of one of four

ports on a PC, for example, is not nearly as critical.

Because Light Peak is intended for distances of 100 m or less—and dispersion is,

therefore, not an issue—spectral-width requirements also can be less stringent than

Telcordia specifies. As a result vendors are able to get closer to 90% to 95% yields on

their VCSELs and photo detectors, rather than the much lower in telecom.”

Intel has also removed the traditional eye-safety requirements, which also translates into

higher yields and lower costs. The traditional telecom module is typically launched at

about 1 mW of power. But the very aggressive power management of the Light Peak

optical module features a launch power much higher than eye safety.

Finally, Intel designed the optical module to be high-volume manufacturable thus further

reducing the cost of production.

21

ADVANTAGES

The light peak optical modules are physically much smaller than those of telecom grade.

The optical modules are designed to be much lower cost and higher performance.

Light Peak can send and receive data at 10 billion bits per second.

The thin optical fiber will enable Light Peak to transfer data over very thin, flexible

cables.

Unlike electrical cables, Light Peak do not faces the problem of EMI, thus can be used up

to 100m.

Light Peak also has the ability to run multiple protocols simultaneously over a single

cable, enabling the technology to connect devices such as docking stations, displays, disk

drives, and more. A simple analogy is it is like loading up many cars onto a high-speed

bullet train.

The data transfer is bidirectional in nature thus enabling devices to transfer

simultaneously.

Quality of service implementation

No Operating System (OS) changes required.

It also supports another feature known as “Hot-swapping” which means the PC needs not

be shut down and restarted to attach or remove a peripheral.

Economies of scale from a single optical solution

Enables I/O performance for the next generation Allows for balanced platform, with

external I/O keeping up with most platform interconnects.

Up to 100 meters on an optical-only cable. Each fiber is only 125 microns wide, the

width of a human hair.

Supports multiple existing I/O protocols over a single cable and smooth transition for

today’s existing electrical I/O protocols.

Can connect to more devices with the same cable, or to combo devices such as docking

stations.

22

DEVELOPMENT STATUS

Intel is working with optical manufacturers to make “Light Peak” components ready to ship in

2010. The company’s intent is to work with the industry to determine the best way to make this

new technology a standard and available on PCs, handheld devices, consumer electronics,

workstations and more.

Fig.14: Demonstration of connection of a HDTV with a laptop

Till date, Intel has suggested that it would be providing controller chip and had collaborated with

different manufactures for various components.

Intel’s Light Peak suppliers include:

Oclaro: VCSELs

Enablence Technologies Inc.: large-area, dual-wavelength 10-Gbps photodiodes

Avago Technologies: optical module with embedded optical engine

SAE Magnetics: optical module

IPtronics: driver and receiver silicon

Ensphere Solutions Inc.: transceiver IC

FOCI Fiber Optic Communications Inc.: connectors and cables

Initial usage models would be focusing on performance and simplification.

Faster media transfer and creation

Flexible design, thinner form factor and simplified cable connections.

Intel is talking to manufacturers of consumer electronics, PCs, peripherals and phones about a

Light Peak standard that will take advantage of 'the full capability' of fiber, although this could

take 'a few years' to finalize. The official process starts later this year. But momentum continues

to increase across the industry with vendors demonstrating the prototype devices.

23

CONCLUSION

Light Peak is a high-speed, multi-protocol interconnect for innovative and emerging client usage

models, that complements other existing interconnects

Light Peak is the name for a new high-speed optical cable technology designed to connect

electronic devices to each other. Light Peak delivers high bandwidth starting at 10Gb/s with the

potential ability to scale to 100Gb/s over the next decade. At 10Gb/s, we can transfer a full-

length Blu-Ray movie in less than 30 seconds. Light peak allows for smaller connectors and

longer, thinner, and more flexible cables than currently possible. Light Peak also has the ability

to run multiple protocols simultaneously over a single cable, enabling the technology to connect

devices such as peripherals, displays, disk drives, docking stations, and more.

Intel is working with the optical component manufacturers to make Light Peak components

ready to ship in 2010, and will work with the industry to determine the best way to make this

new technology a standard to accelerate its adoption on a plethora of devices including PCs,

handheld devices, workstations, consumer electronic devices and more. Light Peak is

complementary to existing I/O technologies, as it enables them to run together on a single cable

at higher speeds.

At the present time, Intel has conducted three successful public demonstrations of the Light Peak

technology and confirmed that the first Light Peak-enabled PCs should begin shipping next year.

The goal of this new developing technology is to build a high-bandwidth, fault-resilient, low-cost

network that can deliver performance isolation across applications. The basic approach to

achieve this target is to integrate low-radix switches into server platform and interconnect severs

directly using multipath topologies.

Thus if the question WHY LIGHT PEAK?? arises, then the answer would be because it is

cheaper as it incorporates cheaper switching components, provide better bandwidth allocation

and performance isolation, uses flexible topologies, integrate multiple protocol devices on to one

cable.

Intel CEO Paul Otellini called Light Peak “the I/O performance and connection for the next

generation,” and confirmed that both Nokia and Sony have publicly announced their support.

Victor Krutul, director of Intel’s optical development team and founder of the Light Peak

program, is even more effusive, calling Light Peak “the biggest thing to happen to the optical

industry ever, or at least since the creation of the laser.”

24

REFERENCES

© http://science.howstuffworks.com

© Electronicsforu magazine, Oct 10

© techresearch.intel.com/ProjectDetails.aspx?Id=143

© en.wikipedia.org/wiki/Light_Peak

© news.cnet.com/8301-13924_3-20025559-64.html

© www.lightpeakinfo.com/

© http://opticalcomponents.blogspot.com/2010/07/laser-optimized-multi-mode-fiber-

lomf.html

© http://www.technewsworld.com/story/68231.html

© http://optics.org/indepth/1/3/6

© http://arstechnica.com/apple/news/2009/09/apple- inspiration-behind- light-peak-optical-

connection-standard.ars

© http://www.lightwaveonline.com/about-us/lightwave-current- issue/Intel-plots-Light-

Peak-interconnect-revolution.html

© http://www.computer.org/portal/web/csdl/doi/10.1109/HOTI.2010.13

© Wooten, E. L., “A Review of Lithium Niobate Modulators for F iber-Optic

Communications Systems,” IEEE Journal on Selected Topics in Quantum Electronics 6,

pp. 69−82, 2000.

© Ido, T. et al., “Ultra-High-Speed Multiple-Quantum- Well Electro-Absorption Optical

Modulators with Integrated Waveguides,” IEEE Journal of Lightwave Technology 14, pp.

2026−2034, 1996.

© Takemoto, A., Watanabe, H., Nakajima, Y., Sakakibara, Y., Kakimoto, S., Yamashita, J.,

Hatta, T., and Miyake, Y., “Distributed Feedback Laser Diode and Module for CATV

Systems,” IEEE Journal of Selected Areas in Communications 8, 1359−1364, 1990.

© Longford, A., and Radloff, B., “The Use of Pre-Molded Leadframe Cavity Package

Technologies in Photonic and RF Applications,” 27th Annual IEEE/SEMICON

conference proceedings, 348−352, July 17−18 (2002).