CUHK 27th of November 2003 1

FIBRE LASERS, CRYSTAL FIBRES AND WHAT TO DO WITH THEM

Presentation to the Chinese University of Hong Kong, November 27th 2003

Guillaume Vienne, Research Center COM, Technical University of Denmark

1. Fiber lasers- High power (Cladding pumped)- Single-frequency (DFBs)- Short pulse (Mode locked)

2. Holey fibres’overview - Photonic Crystal A/S

3. A few applications of PCFs- Spectro- telecom- sensors

CUHK 27th of November 2003 2

CARS setup

fs-lase r

M O

M O

P C F

d e la y

P M T

M O

M O

s a m p le

fi lte rs

x

yz

B S

D M

CARS Experimental setup

40 mm PCF, 0=790 nm

Standard fs laser: 800 nm,50 fs, 76 MHz, 300 mW

Sample is piezo scanned (xy)

Sample: coverglasswith polystyrene beads

Courtesy of Jakob Juul Larsen, NKT Research

CUHK 27th of November 2003 3

Polystyrene:C-H stretch at 3000 cm-1

P = 640 nm,S = 795 nm,E ~ 3000 cm-1

CARS ”mini”continuum

700 750 800 850 9000.0

0.2

0.4

0.6

0.8

1.0

550 600 650 700 750 800 850 900 950 10000.0

0.2

0.4

0.6

0.8

1.0

Inte

nsity

Wavelength [nm]

PCF (0=790 nm)pumped with 25 mW

Courtesy of Jakob Juul Larsen, NKT Research

CUHK 27th of November 2003 4

0

5

10

15

20

05

1015

20

CA

RS

sig

nal [

a.u.

]

µm

Future work: frequency tuning z-scans

CARS signalFWHM ~100 fs

CARS results

S=620 nm, E=3550 cm-1

CARS signal drops to 1%

Courtesy of Jakob Juul Larsen, NKT Research

CUHK 27th of November 2003 5

Two-photon fluorescence detectionDouble-clad PCF with LMA inner cladding

– High intensity of pump beam (guided in single-mode core)

– High NA core (defined by outer cladding) efficiently collects fluorescence

– Single fiber device

– Efficiency enhanced 40x

Reference:Myaing et al.Opt. Lett. 28, 1224 (2003)

Fiber

SampleDichroic Mirror

Filter

Ti: Sapphire Laser

DispersionPrecompensator

RhodamineJELL-O®

Spe

ctrometer

PMTPhoton Counter

CUHK 27th of November 2003 6

Tajima et al.(NTT) OFC´03

ECOC’03 Tutorial, Anders Bjarklev

TRANSMISSION?

CUHK 27th of November 2003 7

Fiber Characteristics

PCFfor transmission

L = 2.6 and 3 km

D = 32 ps/(nm.km) at 1550 nm

S = 0.067 ps/(nm2.km)

= 1.2 W-1.km-1

Loss = 1.7 dB/km

Highly non-linear PCFfor signal processing

L = 50 m

D = 0 ps/(nm.km) at 1552.5 nm

S = -0.26 ps/(nm2.km)

= 18 W-1.km-1

Loss = 58 dB/km

Same scale

Near field

1530 1560 1590 1620

-25

-20

-15

-10

-5

0

5

10

15

disp

ersi

on [p

s/km

/nm

]

wavelength [nm]

dispersion measurement by Kim P. Hansen - Crystal Fibre A/S, PD-paper FA9, OFC 2002

CUHK 27th of November 2003 8

Transmission with OPC at 40 Gbit/s through PCF

PD

CW MZM OBFCW

PC

HNL-PCF

PCF

PCFEDFA

Rx

OBF

PC

S= 1548.86 nm

C= 1555.24 nm

P= 1552.04 nm

2.6 km

3 km

transmitter output after 2.6 km PCF

231-1 PRBS

C. Peucheret & al, Research Center COM

CUHK 27th of November 2003 9

160 Gb/s – 10Gb/s Demultiplexing

loop filter

-

10 GHz

160 Gb/s OTDM data

PCF (50 m)

PC

NOLM

MOD BERML-FRLMUX

SMF 80 km

DCF 12 km

EAM

x4

PD

ERGO PGL

clock recovery

transmitter

PDVCO

High NL coeff -> Short Length -> more stability, less disp & walk offL.K. Oxenløwet & al, Research Center COM

CUHK 27th of November 2003 10

Bend sensor (multi-core PCF)

Reference:Blanchard et al.Smart Mater. Struct. 9, 132 (2000)

Velocimetry:MacPherson et al.,Opt. Comm. 223, 375-380 (2003)

Multi-core PCF bend sensor– PCF with 3 uncoupled cores

– Detect optical phase difference

– Two-dimensional bend sensor

Advantages– Single fiber device

– Relative core positions fixed

– Less sensitive to temperature gradients

– Large freedom in design of fiber (number

and positions of cores)

CUHK 27th of November 2003 11

Evanescent-wave sensing

PCF based evanescent-wave sensors– Evanescent field penetrates into air-holes

– Long interaction length between sample and light

– Measurements on gases and liquids

References:T. Monro et al., Electron. Lett. 35, 1188 (1999)

Y.L Hoo et al., Opt. Eng. 41, 8 (2002)

Y. Hoo et al.IEEE Phot Tech. Lett.15, 1434 (2003)

Absorption measurement on acetylene gas in air-holes of 75cm PCF

CUHK 27th of November 2003 12

Selectivity by hybridization

References:Hoiby et al. Eurosensors 2003

Kiiveri et al., 1996

Hybridization

Single strand Oligo-DNA immobilized inside the air holes

Streptavidin

Biotin

Oligo

Cy5

Cy5

Streptavidin

Biotin

Oligo

Cy5

Cy5

CUHK 27th of November 2003 13

Evanescent-wave sensing in hollow-core PCF

Reference:Jensen et al. CLEO2003

Hollow-core PCF:– Sample volume < 30nL/cm– Sample in all air holes is probed by light

0.70 0.75 0.80 0.85 0.90 0.950

5

10

15

Pen

etr

atio

n (

%)

d/

TT1: = 4m, = 0.65m:

Fundamental mode

– Strong penetration of optical field into sample550 600 650 700

0.0

0.4

0.8

H2O

Cy5-DNA (aq.)

Abs

orba

nce

Wavelength (nm)

CUHK 27th of November 2003 14

Spectrometer

658nm

Expose fiber from the side with laser

Fluorescence measurements Air-Clad PCF with Cy5-Oligo-DNA hybridized on the

inside of the air holes

600 650 700 750 8000

100

200

300

400

Flu

ore

sce

nce

(co

un

ts)

Wavelength (nm)

Cy5-dummy-DNA Cy5-Oligo-DNA

J. B. Jenssen & al, Research Center COM

CUHK 27th of November 2003 15

77°C

89°C

91°C

94°C

Fill & Play: Liquid crystals in PCF

Microheater

T. Tanggaard & al, Research Center COM