SW_LW_sfp

Created by: Imre Baumli 2010, IBM Advanced Tech.

Support Techdocs, Copyright IBM

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What is the difference What is the difference

between the SW and LWbetween the SW and LW

laserlaser transceiverstransceivers

This document describes a operation condition of a semiconductor lasers,

type of the semiconductor lasers, layer structure of the laser devices, operation

wavelength of a device, optical fiber terminologies, coupling losses, optical

transceivers PN coding and the difference between the SW-Short-wave and LW-

Long-wave laser optical transceivers.

In other words why the SW mini GBIC operating at =850 nm and why theLW mini GBIC at =1310 nm or =1550 nm.

5/1/2010 2010, IBM Advanced Tech.


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ContentContent

Operation condition of the semiconductor lasers

Type of the semiconductor lasers

Intensity modulation of the semiconductor lasers

Layer structure of the semiconductor lasers and the operation wavelength*

SW-Short-wave and LW-Long-wave operation range

Optical fiber (terminologies, classification, coupling light into core, losses)

What is the difference between the SW and LW mini GBICs?

SFP-Small Form-Factor Pluggable Part Number coding

Life time of laser diodes and laser safety classes



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The The operatioperationon conditioncondition ofof thethe semiconductorsemiconductor laserslasers

PPrinciplerinciple ofof thethe laserlaser operationoperation

R=99%R=99% R=97%R=97%

activeactive layerlayer

opticaloptical feedbackfeedbackOCOC mirrormirror

HRHR mirrormirror

pumpingpumping

laserlaser outputoutput

Light Amplification by Stimulated Light Amplification by Stimulated

Emission Of RadiationEmission Of Radiation

(Current injection)(Current injection)

During the oscillation process, the light is attenuated and amplifyed in the gain material

and the light beams with same wavelength are coupled out on the OC mirror. The

output of a laser is a coherent electromagnetic field.

where, HR = high reflection mirror, OC= output coupler mirror (semitransparent

mirrors)



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The The principleprinciple ofof thethe stimulatedstimulated emissionemission

hhff

hhff

EiEi

EkEk

NiNi

NkNk

hh=E=E22 --EE11hh=E=E22 --EE11

First the electron is on the higher level and the effect of the incoming stimulating photon will be that the

electron will be emit a clone (a new photon) which will be exactly same with the incoming photon in module,

in polarization and in the phase.

For the laser operation are necessary the following conditions:For the laser operation are necessary the following conditions:

1. Active layer (gain material) which working on the base of the stimulated emission.

2. Pumping power which change the material to active state with population inversion*

3. Optical feedback which usually is created with Fabry-Perot resonator* with (optical resonators)

The function of the resonator is the creation of the high optical energy density and the

hard frequency-selective dealing namely the assurance high spectral purity.



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Type of the semiconductor lasersType of the semiconductor lasers

OpticalOptical

OutputOutput

PowerPower

WavelengthWavelength

Spectral widthSpectral width

FabryFabry--Perot Perot

laserslasers

VCSEL VCSEL Vertical Cavity Surface Vertical Cavity Surface

Emitting lasersEmitting lasers

DFBDFB--Distributed Distributed

Feedback lasersFeedback lasers

= 850 nm= 850 nm=0,85 nm=0,85 nm

= 1300 = 1300 --1310 nm1310 nm= 2= 2--2,75 nm2,75 nm

= 1550 nm= 1550 nm=0,08 nm=0,08 nm

First optical

window

Second optical

window

Third optical

window



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=30=30--40 40 nmnm spectralspectral widthwidth

=0.=0.0088--44 nmnm

LasersLasers

LEDsLEDs

0.5xPmax0.5xPmax

0.5xPmax0.5xPmax

PP

ff

cc

f

c

df

d

df

d

f

c

cf

cf

22

1

!!!

=

=

=

=

=

fc

= 2

ff relationship from relationship from nmnm-- to to HzHz..

SpectralSpectral widthwidth ofof LEDsLEDs andand laserslasers



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VCSELVCSEL Vertical Cavity Surface Emitting lasers:

They are the type of the semiconductor lasers with a monolithic laser resonator, where the emitted light leaves

the device in a direction perpendicular to the chip surface.

The resonator (cavity) is realized with two semiconductor Brag mirrors and between these mirrors is an active

region (gain structure). The active region is electrically pumped with circa 50 mW (tens of milliwatts)

and generated an output power in the range 0,2 5 mW . The current is applied through a ring electrode.

FabryFabry--PeroPerott lasers:

A laser oscillator in which two mirrors are separated by a amplifying medium (gain) with an inverted

population, making Fabry-Perot cavity. Standard diode lasers are Fabry-Perot lasers.

Exist two resonator type: with plan-parallel (R1, R2 = ) and with spherical mirrors (R1, R2 = L/2)The thickness of active layer at heterojunction lasers, strip lasers (mirror separation distance) is usually

d < 1 m or d= 0,2 m.

DFBDFB Distributed Feedback lasers :

Are the type of the laser devices where operating with very small spectral width in the third optical window

and the active layer of the device has integrated a diffraction grating which can be different special form

(normal trapezoidal, rectangular, sinusoidal, ...etc)

Where: ngng - is the group refractive index, BB - is the Bragg wavelength and mm is a integer number

For For m=1m=1 the grating is called firstfirst--order gratorder grating. ing.

The DFB lasers are characterised by The DFB lasers are characterised by very clean spectral linevery clean spectral line widthwidth..

This type is used in the This type is used in the high speed optical communicationhigh speed optical communication and in the cable TV applications.and in the cable TV applications.



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Intensity modulation of the semiconductor lasersIntensity modulation of the semiconductor lasers

In practice for the semiconductor lasers usually it is used the intensity modulation

Necessary power for the modulation is created by a driver circuit

The key parameter of the modulation is the modulation index (modulation deep)

minmax

minmax

PP

PPm

+

=

p

Popt

t

Pmax

Pmin

Pop

Popt

t

Po

Pmax

Pmin

The modulation index variation during digital and sinusoidal modulation

The main parameter of the light source is the outgoing optical power

What is the intensity modulation?

If the current of the device (laser diode) containing a modulation term, in this case the modulator current

will be change the outgoing optical power of the device.

In the intensity modulation it is required that the device to be modulated at high frequency, which is perfect for

the semiconductor lasers.



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Usually the device is modulated at third part of Usually the device is modulated at third part of

the the relaxation resonance frequencyrelaxation resonance frequency FFMM=(1/3)f=(1/3)fRR

The maximal value of the The maximal value of the relaxation resonancerelaxation resonance

frequencyfrequency today is today is 10 10 GhzGhz..II

ith

Popt

iii

PxPx

The other very important is, that the device must be modulated on the linear part of the

characteristic (after the ith - threshold current).

During the optical transfer (communication), the device is not powered down completely

(totally), only until the threshold current.

The modulation process is characterized by chirp because during the variation of the

optical power, is change the value of the laser frequency.



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Layer structure of the semiconductor lasersLayer structure of the semiconductor lasers

light light

emissionemission

Lower Lower

BraggBragg

reflectorreflector

activeactive

layerlayer

UpperUpper

BraggBragg

reflectorreflector

The total The total tichnesstichness of the of the

active layeractive layer is usually few is usually few

micrometer.micrometer.

The mirror separation distance The mirror separation distance

is usually is usually L < 1 cmL < 1 cm..

HR = HR = high reflection mirrorhigh reflection mirror

OC = OC = output coupler mirroroutput coupler mirror

R1=L/2R1=L/2 R2=L/2R2=L/2

Spherical resonatorSpherical resonator

amplifyingamplifying

mediummedium

R1=R1= R2=R2=

PlanePlane--parallel resonatorparallel resonator

amplifyingamplifying

mediummedium

LL

HRHR

mirrormirror

OCOC

mirror

HRHR OCOC

Uniform grating DFB laserUniform grating DFB laser

The The grating periodgrating period (():):

========mmBB/2/2nnggFor For 1,5 1,5 m m InGaAsPInGaAsP laser,withlaser,withfirst order grating the typical value first order grating the typical value

of of ngng=3,4=3,4

and and ========0,23 0,23 mm

Are used usually at Are used usually at 40km/2Gb40km/2Gb

or or 10km/4Gb10km/4Gb optical transfers.optical transfers.

GaInAsPGaInAsP

GaInAsP waveguide layer

n-InP buffer layer

n-InP substrat

n-InP buffer layer

For laser operation it is necessary for:

- active layer (which working after stimulated emission)

- population inversion (pumping)

- optical resonator (for light wave amplification)



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g1

g2

((g1=1, g2=1)g1=1, g2=1)

planeplane--parallelparallel

g1=g1=--1, g2=1, g2=--11

sphericalspherical

Stability of the FP resonators:Stability of the FP resonators:

They must be They must be fullfillfullfill the stability criteria:the stability criteria:

0< g10< g1g2 g2



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TransferTransfer characteristiccharacteristic ofof FP FP resonatorresonator

TPF=I/I0

dB

f (Hz)

R=0.75

R=0.90

R=0.99

-15

-25

-40

-1 0 +1

FSR=FSR=f=c f=c //2d2d FreeFree SpectralSpectral RangeRange

FWHM=FWHM=ff

IImaxmax--IIminmin

IImaxmax--IIminmin //22

)2

sin(1

2(

2

0

1

1

n

f

R

RII

TFP

+

==

((AiryAiry transfertransfer functionfunction ofof filter)filter)

Between the mirrors the material is air with Between the mirrors the material is air with n=1n=1, we have , we have

((TheoreticalTheoretical AiryAiry transfertransfer functionfunction))

)2sin(1

2(

2

0

1

1

+

==

fR

RII

TFP



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GaGaxxInIn11--xxAsAsyyPP11--yyactive layeractive layer

(d=0,2 (d=0,2 m)m)p p InPInP subsratsubsrat, 2 , 2 mm

SiO2metal metal

contactcontact

metal metal

contactcontact

p p GaInAsPGaInAsP subsratsubsrat

n n InPInP subsratsubsrat, 1 , 1 mm

n n GaInAsPGaInAsP subsratsubsrat

GaAsGaAs oror

GaGaxxAlAl11--xxAsAsactive layeractive layer

(d=0,2 (d=0,2 m)m)p p GaAlAsGaAlAs subsratsubsrat, 2 , 2

mm

SiO2metal metal

contactcontact

metal metal

contactcontact

p p GaAsGaAs subsratsubsrat

n n GaAlAsGaAlAs subsratsubsrat, 1 , 1

mm

n n GaAsGaAs subsratsubsrat

Double Double heretojunctionheretojunction structurestructure

d=0,2 d=0,2 mm

lossloss

amplificationamplification

losslossOptical powerOptical power

distribution

Refractive Refractive

index index

variationvariation

Temperature variation

of the threshold current: IIthrthr=I=Ithrthr(0)(0)expexp(T/T0)(T/T0)

The threshold current for 0 Kelvin is (for DH lasers, I(T)=0 if T=0 K):

where: L is the mirror distance, d- diffusion thickness, - attenuation,i internal quantum efficiency, nGaAs = 3,6 refractive index , -confinement factor and r1=r2= r =(nGaAs nair/nGaAs

+nair)2 = 0,32 are the reflection coefficients

)(1

ln2

118)0(

21

2TI

L

dqf

rrI outin

i

thr+

+

+

=



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Layer structure of SW and LW laser diodes and the operation wavelength

The The latticelattice constantconstant andand thethe energyenergy bandband gapgap forfor differentdifferent materialsmaterials

aa00(GaAs) = 5.6533 (GaAs) = 5.6533 AAaa00(InP) = 5.8688 (InP) = 5.8688 AAaa00(GaP) = 5.4512 (GaP) = 5.4512 AAaa00(InAs) = 5.0584 (InAs) = 5.0584 AAaa00(AlAs) = 5.6605 (AlAs) = 5.6605 AAaa00(GaSb) = 6.10 (GaSb) = 6.10 AA

1 angstrom=101 angstrom=10--88 cmcm

GaPGaP

6.106.10 6.156.155.6533 5.6533 5.4512 5.4512 5.86885.8688

6.0584 6.0584 5.66055.6605

F

o

r

b

i

d

d

e

n

F

o

r

b

i

d

d

e

n

b

a

n

d

b

a

n

d

E

g

E

g

(

e

V

)

(

e

V

)

LatticeLattice constantconstant aa00 ( ( AA--angstromangstrom))

InPInP

InAsInAs

GaAsGaAs

AlAsAlAs

AlSbAlSb

GaSbGaSb

2.32.3

0.40.4

1.41.4

1.31.3

2.22.2

1.651.65

0.70.7



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GaGaxxAlAl 11--xxAsAsactive layeractive layer

GaGayyAlAl 11--yyAsAs

GaGayyAlAl 11--yyAsAsSW laser device layer structure First optical window range:

= 820 nm 880 nm

The active layer GaGaxxAlAl11--xAsxAs which is doped in x % in Al-aluminium, is lattice matched

to GaGayyAlAl11--yyAsAs layer which is doped in y >>>> x % in Al. The percent of the aluminium content will be modify theEg of the thernary and will be modify the wavelengthwavelength ofof thethe emittedemitted radiationradiation..

The properties of the semiconductor compoud can be described by Vegards law:

a(Gaa(GaxxAlAl11--xxAs) = As) = xxa(AlAsa(AlAs) ) (1(1--x)x)a(GaAs),a(GaAs), where a - is the lattice constant.

The lattice constant and energy band gap value of the materials resulting from the graphic.

5,6605x + 5,6533 5,6533x = 5,6605y + 5,6533 5,6533y0,0072x = 0,0072y x y (y >>>> x)

For the energy bandgap (forbidden band of thernary structure) we can apply same law:

Eg(GaEg(GaxxAlAl11--xxAs) = xAs) = xEg(AlAs) Eg(AlAs) (1(1--x)x)Eg(GaAsEg(GaAs)) Eg(x) = 2,2x +(1-x) 1,4 = 0,8 x +1,4

For 0,850 nm = 1.24/Eg for first optical window the forbidden band must be Eg = 1,24/0,850 = 1,45 eV1,45 = 0,8 x +1,4 x = 0,0625 Al % and y must be higher as xFrom the definition of the operation wavelength, resulting for the SW-short wave operation range:

====0,855 m = 855 nm which is the first optical window.][24,1

mEgEg

hc

h

EvEc

c

f

c ====



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2nd optical window: =1285 1330 nm

3rd optical window: =1525 1575 nm

GaGaxxInIn11--xxAsAsyyPP11--yyactive layeractive layer

LW laser device layer structureInP

InP

The active layer of the LW laser device is the material system - GaGaxxInIn11--xxAsAsyyPP11--yy - gallium indium

arsenide phosphide which is doped in x % in In indium and y % in P-phosphide.

This material system can be used for the realization of lasers in the spectral window around

1310 nm and 1550 nm which are the second and third optical windows.

The properties of this semiconductor compound (GaGaxxInIn 11--xxAsAsyyPP11--yy) ) can be described by

Vegards law.

a(Gaa(GaxxInIn11--xxAsAsyyPP11--yy ) = xy) = xya0(GaAs) + x(1a0(GaAs) + x(1--y)y)a0(GaP) + (1a0(GaP) + (1--x)yx)ya0(InAs) + (1a0(InAs) + (1--x)(1x)(1--y)y)a0(InP) a0(InP) = = == 5.65335.6533xy + 5.4505xxy + 5.4505x(1(1--y) + 6.0584(1y) + 6.0584(1--x)x)y + 5.8688(1y + 5.8688(1--x)x)(1(1--y)y)

Using this law and know the semiconductor compounds GaAs, GaP, InAs, and InP it is

possible to determine the coefficients x and y and the operation wavelength of the laser

device.



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a(Gaa(GaxxInIn11--xxAsyP1AsyP1--y ) = a0(x,y) =5.8688 y ) = a0(x,y) =5.8688 0.4176x + 0.1896y + 0.0125xy0.4176x + 0.1896y + 0.0125xy

The The materialmaterial shystemshystem GaGaxxInIn11--xxAsAsyyPP11--yy itit is is latticelattice matchedmatched toto InPInP layerlayer ((withwith latticelattice constantconstant

a(InPa(InP) =5,8688) =5,8688) :) :

5.8688 5.8688 0.4176x + 0.1896y + 0.0125xy = 5.8688 0.4176x + 0.1896y + 0.0125xy = 5.8688 0.4176x = 0.1896y + 0.0125xy0.4176x = 0.1896y + 0.0125xy

For the x % and y % of In and P resulting the following relationship:

0.100125.04176.0

1896.0

= yy

yx

x

xy

=0125.01896.0

4176.0

If y=1 y=1 resultingresulting x=0.468x=0.468, , butbut allwaysallways y y must be must be higherhigher asas x x ((y>xy>x))

Resulting x < 0,468 (the In-indium % of the active layer)

Egnm

24.11310 =

For 1310 nm

For 1550 nm

Egnm

24.11550 = eVEg 94.0

310.1

24.1==

eVEg 80.0550.1

24.1==



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Applying the Applying the VegardsVegards lawlaw for the energy band gap of the active layer for the energy band gap of the active layer resuktingresukting::

Eg(GaEg(GaxxInIn11--xxAsAsyyPP11--yy) = ) = xyxyEg(GaAsEg(GaAs) + x(1) + x(1--y)y)Eg(GaP) + (1Eg(GaP) + (1--x)yx)yEg(InAs) + (1Eg(InAs) + (1--x)(1x)(1--y)y)Eg(InP) =Eg(InP) =

= xy= xy1,4 + x(11,4 + x(1--y) y) 2,3 + (12,3 + (1--x) x) yy 0,4 + (10,4 + (1--x) x) (1(1--y) y) 1,3 =1.1,3 =1.3 + x 3 + x -- 0.9y0.9y

For Eg = 0,94 eV if x=0,36 (In %) resulting y=0,8 (P %) and resulting = 1310 nm

0,94 = 1.0,94 = 1.3 + 0,36 3 + 0,36 -- 0.9y0.9y y=0,8 =1.24/0,94 = =1.24/0,94 = 1310 1310 nmnm (2(2--nd nd opticaloptical windowwindow))

For Eg = 0,80 eV if x=0,46 (In-indium %) y=1,06 (P-phosphide %) and resulting = 1550 nm

0,80 = 1.= 1.3 + 0,46 3 + 0,46 -- 0.9y0.9y y=1,06 =1.24/0,80 = =1.24/0,80 = 1550 1550 nmnm (3(3--rd rd opticaloptical windowwindow))



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SW-Short Wave and LW-Long Wave operation range

TheseThese peakspeaks cancan be be attributableattributable toto

OH OH hydroxilhydroxil ion ion contentcontent ofof thethe glassglass

fibrefibre..

After 1800 nm the attenuation increase

dinamically and appears the nonlinear effects

namely the refraction index n=n(P) from the

core deppend on the optical power of the light.

-Raman scattering PRkszb=570mW

-Brillouin scattering, PBkszb=1mW

-FWM - Four wave mixing

Mix the frequences in 1.55m band and appears noises

[[[[[[[[dBdB]]]]]]]]

[[[[[[[[nmnm]]]]]]]]850850 13101310 15501550 18001800400400

11--2 dB2 dB

0.4 dB0.4 dB

0.10.1--0.2 dB0.2 dB

At At 1550 nm1550 nm we have the we have the

theoretical minimum optical loss theoretical minimum optical loss

for silicafor silica--based fibers (quartz) based fibers (quartz)

about 0,2 dB/km.about 0,2 dB/km.

3rd optical window

(SMF - SM fibre)

2nd optical window

(SMF - SM fibre)

1st optical window

(MM fibre)

1/4

(Reilay scattering)

LW Operation Range

Short bandShort band (1450(1450--1510)1510)

Long bandLong band (1570(1570--1625)1625)

Conventional bandConventional band (1525(1525--1560)1560)

SW Operation Range

PinPout=Po10-Loopticalptical powerpower lossloss

L=1kmL=1km

glassglass

fiberfiber



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Classification of optical fibers

1.1. AAfterfter the refractive index profilethe refractive index profile:: SI SI Step Index FibersStep Index Fibers

((GRINGRIN--GradedGraded Index Index FiberFiber))

-- One dimensionOne dimension paraparabolicbolic

-- Two dimension parabolicTwo dimension parabolic

2.2. AAfterfter the propagation modesthe propagation modes:: SM-Single Mode Fiber

MM Multi Mode Fiber

50/62.5 m 9 m

50 m

SW LW

3.3. AAfterfter dispersion characteristicdispersion characteristic::

DSFDSF-- DispersionDispersion ShiftedShifted FiberFiber D D ======== DwDw + + DmDm

NDSFNDSF-- NotNot DispersionDispersion ShiftedShifted FiberFiber

NZNZ DSFDSF-- NoNonn--ZZeroero DispersionDispersion ShiftedShifted FiberFiber

more index profilesmore index profiles (for (for DS DS fibersfibers)

Dispersion ======== waveguide dispersionwaveguide dispersion + + modal dispersionmodal dispersion



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Dispersion Shifted Fiber and Dispersion Flattened Fiber

Dispersion Shifted Fiber

- Increase waveguide dispersion at higher wavelengths

- This can be eliminate with various refractive index profiles and

the result is Dispersion Shifted Fiber.

Dispersion Flattened Fiber

- They are fibers with low dispersion over a range of wavelengths with

complex index profiles.

Dispersion Flattened Fiber index profiles



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Technical terminology of optical Technical terminology of optical fibersfibers

-- AttenuationAttenuation

NANA -- Numerical Aperture*Numerical Aperture*

-- Refractive Index DifferenceRefractive Index Difference

-- Maximum Time DifferenceMaximum Time Difference

DD Dispersion Dispersion

VV -- Normalized Frequency**Normalized Frequency**

M M Number of modesNumber of modes

RR Bend Radius* (R minim)Bend Radius* (R minim)

=c

L n 1

= = --1010lg(Pout/Pin)lg(Pout/Pin) [ dB/km][ dB/km]

NA = sinNA = sinkk = (n= (n1122 nn22

22 ))1/21/2

= (n= (n1122 nn22

22 ))/2n/2n1122

= 3

2

4)( ooS

D1200 nm 1200 nm 1160600 0 nmnm

--operating wavelengthoperating wavelength

NAaa

V nn ==

22 2

2

2

1

M M VV22/2/2 ][405,2

2nm

NAac

NAR acritic2

/=

CutCut--off wavelengthoff wavelength

(for Step Index fibers)

(for SMFs)

V = 2,405



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Coupling light into fiber

3

NumericalNumerical aapertureperture lossloss

FressnelFressnel reflectionreflection lossloss

nn22

nn11acceptanceacceptance conecone

NA=sinNA=sinkk

((numericalnumerical apertureaperture))

NA=(n12-n2

2)1/2

((halfhalf angleangle ofof

acceptance acceptance conconee))

n1>>>>n2

n2

SiOSiO22--corecore

claddingcladding

criticcritic

kk

1

2

n=1

50 50 mm

125 125 mm

Ray propagation in the Step Index fiberRay propagation in the Step Index fiber

Coupling light into fiberCoupling light into fiber

Source

Core

SW LD for MMF

LW LD for SMF

Psource core

max=arcsinNA

Pfiber

Laser Diode

f()



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core

AreaArea mismisssmatchmatch losslossSource

core

FressnelFressnel rreflectioneflection lossloss

Source

NumericalNumerical apertureaperture losslossSource

core

L = -10lg() [ dB]

The coupling efficiency:

sin2

max

2/

=== NAPsourcePfiber

The coupling loss in dB:The coupling loss in dB:

L=L=--1010lg(1lg(1--r)r) ======== 0,180,18 [[dBdB]]

rr== (n1(n1--n/n1+n)n/n1+n)22 == 0.04 0.04

(for glass/air: n(for glass/air: n ==1,5, n11,5, n1==1)1)

(Fresnell reflection coefficient)

aa

NAa

NAa

s

c

ss

cc =

2

The coupling loss in dB:L = -10lg(ac/as) [ dB]

LossesLosses atat lightlight couplingcoupling intointo a a fiberfiber



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Normalized Frequency and the cutNormalized Frequency and the cut--off wavelengthoff wavelength

NAaa

V nn ==

22 2

2

2

1NF value is: V ==== 2,405

Is the limit of the single mode operation.Is the limit of the single mode operation.

Base modes

HE11TMTM0101

TETE0101

HEHE1111 HHyybridbrid Electromagnetic ModesElectromagnetic Modes

TMTM0101 TransTransverseverse MagneticMagnetic ModesModes

TETE0101 TraTrannssverseverse Electric ModesElectric Modes

V

nn11--corecore

nn22--claddingcladding

nneffeff==KK

V=2.405V=2.405

Higher modesHigher modes

Single Mode Single Mode

operation rangeoperation range

2

2

mod

VN es

The number of modesThe number of modes

Multi Mode operation

range

We can eliminate the higher modes using inequality We can eliminate the higher modes using inequality V V 2,4052,405 a a 2,405/22,405/2NANA

for SMF-Single Mode Fibers a 9 m (for LW fibers) and for cut-off wavelength

2a2aNANA /2,405 ==== 1,306dNA [[[[nm]]]] (SMF small core diameter, and cut-off value > 1260)



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What is the difference between the SW and LW mini GBICs?

All mini GBIC has integrated a PIN photodiode and a laser transceiver

(optical transceiver)Laser transmitter (Laser transmitter (laserdiodelaserdiode))

VCSEL or FPVCSEL or FP--FabryFabry--Perot & DFB Perot & DFB

lasers lasers

Rise/Fall time*Rise/Fall time* trtr = 90 = 90 psps

mini

GBIC/SFP

Receiver (PIN photodiode)Receiver (PIN photodiode)

Rise/Fall time*Rise/Fall time* recrec = 50 = 50 psps

(where GBIC = Gigabit Interface Converter)

The rise/fall time values are the followings for the 4Gb/s SFP Small Form-Factore Pluggable devices:

for receiver 50 ps for transceiver 90 ps.

The FP laser transceivers are used usually for 2Gb/s or 4Gb/s up to 4 km optical reach and the DFB

laser transceivers are used from 4 Gb/s or 8 Gb/s from 10 km or higher link distance.

optical channeloptical channel

TXTX

RXRX



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How we can list the WWPN -Word Wide Port Number, location code and port speed of the the host adapters

in AIX environemnt in case of a DS8k storage?

vbb08c0 # lsrsrc -xt IBM.EssHAPort logicalName locationCode wwpn portSpeed

"cpssfc0233" "U1300.001.RJ69540-P1-C4-T3" "500507630813c6ac" "4 Gb/s"

"cpssfc0232" "U1300.001.RJ69540-P1-C4-T2" "50050763081386ac" "4 Gb/s"



"cpssfc0303" "U1300.001.RJ69575-P1-C1-T3" "500507630818c6ac" "4 Gb/s"




vbb08c0 #

Each host adapter is populated with 4 mini GBICs (SFPs).

vbb08c0 # lsdev -C|grep cpssfc023

cpssfc023 Available 02-02-03 IBM Yukon FC adapter





vbb08c0 #

T0

T1

T2

T3

Host adapter ports4 pieces pluggable

optical transceivers



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Summary

The difference lies in layer structure of the laser optical transceivers.

In case of the SW active layer structure from the Vegards law resulting different value for the

energy bad gap as for the LW quaternary structure, therefore the lamda will be different.

From the definition of the laser operation wavelength resulting different value for SW and for LW active layer

structure.

In first case [820 880] nm and in case of the LW active layer structure resulting [1285 1575] nm.In case of the thernary (three layer structure) resulting the following operation wavelength for the laser.

GaGaxxAlAl11--xxAsAsactive layer

dopped in X % Al-aliminium

GaGayyAlAl 11--yyAsAs

GaGayyAlAl 11--yyAsAsSW laser device layer structure

[820 880] nm

nmch

h

EEc

fc

vc

850AsAlGaEAsAlGa )()( X-1XgX-1X

=

==

(1st opt. window)

Emitted wavelength for SW active layer



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GaAs emit radiation at ==== 870 nm wavelegth. The 1st optical window is at ==== 850 nm.If the GaAs is dopped in X % in Al-aluminium, the Eg of the thernary GaGaxxAlAl11--xxAsAs will be change

which will be modify the wavelength of the emitted radiation. For the laser diodes which operating

in 1st optical window the active layer is GaGaxxAlAl11--xxAsAs (doped in X % in Al) which is lattice matched

to the GaGaYYAlAl11--YYAs As layer (dopped in Y % in Al, where Y > X).

If x > 0,37 resulting indirect transition structure

If x



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For the laser diodes which operating at 2nd or 3rd optical windows the active layer structure

is GaGaxxInIn11--xxAsAsyyPP11--yy which is lattice matched to the InP layer.

The active layer is dopped in X % in In-indium and in Y % in P phosphide.

For x < 0,47, y 2,2x resulting the direct transition structure.

The variation of X and Y will be change the value of Eg of the quaternary which will be modify

the wavelength of the emitted radiation between [1285 1575] nm.

[1285 1575] nm

GaGaxxInIn11--xxAsAsyyPP11--yyactive layer dopped in

X % in In-indium and Y % in P- phosphide with Y > X

LW laser device layer structure

InP

InP

In case of the quaternary (four layer structure) the operation wavelength of the

laser transceiver will resulting for second or third optical window.

nmP

ch

hPEE

cfc

YYvc

1550/1310AsInGaEAsInGa )()( 1YX-1Xg1YX-1X

=

==

Emitted wavelength for LW active layer



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FINISAR Part FINISAR Part NumberNumber codingcoding: F : F --TLFTLF -- 8585 -- 2828 -- PP-- 22 -- B B -- NN -- VV

F = FinisarF = Finisar

85 = 850 nm (1st optical window)

(VCSEL with PIN receiver)

13 = 1310 nm (2nd optical window)

FP Fabry Perot w PIN receiver


DFB- Distributed Feedback w PIN receiver

85 = 850 nm (1st optical window)

(VCSEL with PIN receiver)


FP Fabry Perot w PIN receiver


DFB- Distributed Feedback w PIN receiver

TRX-XFP TRX-XFP

24 = 2x, 4x FC (2, 4 Gb/s operation speed)

28 = 8x FC (8 Gb/s operation speed)24 = 2x, 4x FC (2, 4 Gb/s operation speed)

28 = 8x FC (8 Gb/s operation speed)

P = Pluggable (SFP)P = Pluggable (SFP)

1 = 1st generation , 2 = 2nd generation1 = 1st generation , 2 = 2nd generation

B = standard bail , W = wide bailB = standard bail , WW = wide bail

N = Extended Temperature (-5 to -20 C to + 85 C)

T = Industrial temperature (-40 to 85 C)

NN = Extended Temperature (-5 to -20 C to + 85 C)

TT = Industrial temperature (-40 to 85 C)

V = Standard reach w rate select

D = Reduced reach w rate selectVV = Standard reach w rate select

DD = Reduced reach w rate select



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SSW W AVAGOAVAGO Part Part NumberNumber codingcoding: : AFAFBRBR -- 5757 -- DD7A7A PPZZ

AFAF = = AvagoAvago Fiber OpticsFiber Optics

BRBR = multimode device= multimode device

5757 = SFP (a 59 would be SFF)= SFP (a 59 would be SFF)

DD = 8/4/2G (= 8/4/2G (RR would be 4/2/1G)would be 4/2/1G)

77 = Gen 2 (= Gen 2 (55 = Gen 1)= Gen 1)

AA = extended temp (= extended temp (--10 to 85 C)10 to 85 C)

PP = bail latch option = bail latch option

ZZ = = RoHSRoHS compliantcompliant

LLW W AVAGOAVAGO Part Part NumberNumber codingcoding: : AFAFCTCT -- 5757 -- DD 5A5ATTPPZZ

AFAF = = AvagoAvago Fiber OpticsFiber Optics

CTCT = single mode device= single mode device

5757 = SFP (a 59 would be SFF)= SFP (a 59 would be SFF)

DD = 8/4/2G (R would be 4/2/1G)= 8/4/2G (R would be 4/2/1G)

55 = Gen 1 = Gen 1

AA = extended temp (= extended temp (--10 to 85 C)10 to 85 C)

TT == DFB source for 10DFB source for 10--kmkm ((NN is for 30 km device)is for 30 km device)

P P = bail latch option= bail latch option

Z Z = = RoHSRoHS compliantcompliant



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Life time of laser diodes

The lifetime of the laser device can be approximated

by the Arrhenius equation:

A scaling factor (device constant, A 0,95 1)Ea activation energy in [ eV ]

K Boltzmanns constant k =8,6 x 10 -5 eV/K

T temperature [Kelvin]

For 1310 nm = 1,24/Eg [m] Eg = 0,8 eVwe using Ea < Eg 3 eV (for Ge = 0,7- 0,8 eV)

Ea - is the amount of energy which liberate (make free) the

chemical bindings from the semiconductor material.

e10,48

e11,15

e11,5

e12

exp(Ea/kT)

34.476,10 h60 C 333,15 K

67.371 h40 C 313,15 K

95.000 h30 C 303,15 K

156.000 h27 C 300,15 K

t lifetime [hours]Temperature

T K=273,15 + T C

20 30

Hours

Temperature

27 40 60

34.000

67.000

95.000

156.000

For laser diodes which operating at T=40 C the lifetime ist = 67370 h = 7,69 years

For T=22 C the lifetime is about t =170.000 h = 19,4 years

eAtkTEa /=



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LASERLASER Safety Classes (after IEC 60825Safety Classes (after IEC 60825--1 standard)1 standard)

TX Optical Output Power, RX Optical Input Power (average) parameters for AFCT-57R5APZ Avago SFP

(lambda =1310 nm/LW, link range=4 km, type: Avago mini GBIC)

Po Optical output power of the laser -9,5 dBm (minimum) < Po < - 3 dBm (maximum value)

P_in Input optical power (rec. sensibility) -15,37 dBm (minimum) < P_in < - 3 dBm (maximum value)

Remark: x = 10 lg(P) lgP = x/10 P = 10 (x/10) (P-arbitrary power in mW, x dBm decibell milliwatt)For example: -3 dBm P = 10 (-3/10) = 10 (-0,3) = 1/10 0,3 = 1/1,995 = 0,5012 mW < 1 W [ Class 1 ]

Class 1 The resulting laser beam optical power is under the MPE Maximum Permissible Exposure

(This class is not dangerous and not able to produce significant eye trauma.)

Class 2 Low power visible continuous wave lasers with maximum outgoing optical power = 1 mW

Attention: Don't look into the ray of laser-light coming out of optical transceivers.

Class 3a Medium power lasers with outgoing optical power = 5 mW with other restriction (limitation)

which is that: E = d/dA [W/m2] the laser beam radiated surface power 25 W/m2 (laser pointers)

Class 3b Medium power lasers with outgoing optical power = [ 5 mW 500 mW ] continuous wave

They are very hazardous for the eye and can cause blindness. (can burn the retina of the eye)

Class 4 * High power lasers with outgoing optical power > 500 mW (no over limit for the outgoing optical power).

They can produce eye or skin trauma and they are flammable.

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