8/7/2019 Poster_WS

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Wavelength Selector / Tunable Filter

Introduction

Filter Shape, Bandwidth & Crosstalk

Low Insertion Loss and PDL

Hereafter, measured data is presented of a prototype unit. The unit wastested over a wavelength range of 120 nm from 1515 nm to 1635 nm.

End State:

t = TN = 60 ms(typicalvalue)

Intermediate State:

t = Ti

Initial State:t = T0 = 0 ms

Tunable FilterWavelength Selector

Switching

i

The Wavelength Selector and Tunable Filter are the first products in

YENISTAs product line of agile optical solutions. Operation of both is

depicted in the table below.

Tuning

N N

00

Fast Switching / Tuning

High Wavelength Accuracy

Absolute wavelength is accurate to 10 pm and wavelength can be set with aresolution of 2 pm.

Low Group Delay Variation

Low PMD

1,00

1,50

2,00

2,50

3,00

3,50

1 50 0 1 515 1530 154 5 156 0 15 75 15 90 1605 1 620 1635 165 0

Wavelength (nm)

InsertionLoss(dB)

< 0.8 dB

Insertion loss of the Tunable Filter is specified: IL < 3.0 dB over the C-band.Measured data over a wavelength range from 1515 nm to 1635 nm (120 nm)

is shown below. In this example, IL = 2.3 0.1 dB over 1515 nm to 1570 nmand IL increases from 2.4 to 3.0 dB over 1570 nm to 1635 nm (total flatness

over 120 nm < 0.8 dB).

-60

-50

-40

-30

-20

-10

0

1540 1542 1544 1546 1548 1550 1552 1554 1556 1558 1560

Wavelength (nm)

Inser

tionLoss(dB)

-60

-50

-40

-30

-20

-10

0

1510 1512 1514 1516 1518 1520 1522 1524 1526 1528 1530

Wavelength (nm)

InsertionLoss(dB)

Filter shape is Gaussian and remains

stable over the full wavelength range

from 1515 nm to 1635 nm. The

crosstalk level is specified < 45 dB.

Measured filter curves are shown

for three wavelengths:1520 nm, 1550 nm and 1630 nm.

It is observed that the crosstalk levelgoes down to 60 dB at 4 nm from the

center wavelength and that the filterhas a clean symmetric Gaussian

shape over a dynamic range of at

least 30 dB.

The filter shape has a 1 dB bandwidthof 0.20 dB, a 3 dB bandwidth of

0.35 nm and a 3/20 dB ratio of 0.37.

Other bandwidths are available uponrequest. Insertion loss of the Gaussian

shape can be widened in exchangeto higher insertion loss.

Insertion loss of the Wavelength Selector is specified: IL < 3.5 dB over the

C-band. PDL is below 0.2 dB for both devices.

-60

-50

-40

-30

-20

-10

0

1620 1622 1624 1626 1628 1630 1632 1634 1636 1638 1640

Wavelength (nm)

InsertionLoss(dB)

Constant Bandwidth over WavelengthAn important feature is the constant bandwidth of the filter over the full wavelength

range. Measured data is shown below.

0

0,2

0,4

0,6

0,8

1

1,2

1500 1515 1530 1545 1560 1575 1590 1605 1620 1635 1650

Wavelength (nm)

Spectralwidth(nm)

1 dB

3 dB

20 dB

0,00

0,05

0,10

0,15

0,20

0,25

0,30

0,35

0,40

0,45

1500 1515 1530 1545 1560 1575 1590 1605 1620 1635 1650

Wavelength (nm)

Spectralw

idthratio

3/20 dB ratio

1/20 dB ratio

Switching / Tuning speed to any wavelength is faster than 100 ms (typical speed

is 60 ms)..

1598

1599

1600

1601

1602

1603

1604

1605

1606

1607

1608

1609

1610

1549,5 1549,6 1549,7 1549,8 1549,9 1550 1550,1 1550,2 1550,3 1550,4 1550,5

Wavelength (nm)

GroupDelay(ps)

2.21 ps

Group delay variation is below 3 ps over the 3 dB bandwidth of the filter. Datahas been measured over the C-band, see an example below.

PMD is below 0.3 ps over the 3 dB bandwidth of the filter. Data has been

measured over the C-band.