WP5: OTDM-to-WDM conversion WP5: OTDM-to-WDM conversion updateupdate

ORC CONTRIBUTION – F. Parmigiani

TRIUMPH meeting 14-12-2006

2 TRIUMPH OTDM-to-WDM conversion update14-December-2006

CONFIDENTIAL

WP5: OTDM-to-WDM conversion

Conversion provided by a rectangular shaped, linearly-chirped pulse Implementation of this conversion is more challenging at higher bit rates

Condition of one-to-one mapping implies a precise relationship between:chirp of the broadband signalstrength of the nonlinear XPM interaction

Optical Switch

OTDM data SignalWDM data Signal

Broadband Signal

WDM channel separation crosstalk between the WDM channels

3 TRIUMPH OTDM-to-WDM conversion update14-December-2006

CONFIDENTIAL

WP5: OTDM-to-WDM conversion

Alternative technique: 4 independent and synchronized WDM channelsPulse carving at 40 GHz using EAMs.

WDM data Signal

Broadband SignalOTDM data Signal

DFB1DFB2DFB3DFB4

EAM1

EAM2

EAM3

EAM4

1

2

3

4

4 TRIUMPH OTDM-to-WDM conversion update14-December-2006

CONFIDENTIAL

Extinction ratio degradation in NOLMs

See for example: Sakamoto et al., PTL, vol.16, n.2, 2004

Time

Phase

Shift XPM

Co-propagating Signal

Time

Phase

Shift

XPM

Counter-propagating Signal

Time

Inte

nsi

ty Control Pulse

Time

Inte

nsi

ty

XPM

Output Signal

Co-propagating signal

Counter-propagating

signal

Counter-propagating signal suffers from XPM induced by the time-average power of the control pulses at high bit rates (160Gb/s)

the extinction ratio of the switch is compromised at high bit rate (160Gb/s)

5 TRIUMPH OTDM-to-WDM conversion update14-December-2006

CONFIDENTIAL

Initial Switching settings

TFWHM=2ps (Gaussian)

=1542.5nm

Pave=16dBm

TFWHM=4.2ps (Gaussian)=1554nm

Spacing=4.8nm (600GHz) Pave=0dBm

?

?

HNLF: lenght=0.5km loss=1.44 dB/km Slope=0.01ps/nm2/km

6 TRIUMPH OTDM-to-WDM conversion update14-December-2006

CONFIDENTIAL

Characteristics of switched pulses

Dispersion@1550nm[ps/nm/km]

-1.0 -0.5 0.0 0.5 1.0

Tem

pora

l Bro

aden

ing

(ps)

1

2

3

4

5

6

Ch1 Ch2Ch3Ch4

Dispersion@1550nm[ps/nm/km]

-1.0 -0.5 0.0 0.5 1.0

Sw

itchi

ng E

ffic

ienc

y

0.0

0.1

0.2

0.3

0.4

0.5

Ch1 Ch2 Ch3 Ch4

7 TRIUMPH OTDM-to-WDM conversion update14-December-2006

CONFIDENTIAL

Switched pulses in time and wavelength

~5dB

Pcontrol=16dBm

D@1550=0ps/nm/km

D@1550=-1ps/nm/kmPcontrol=16dBm

~ 30dB

>30dB

10dB

13%

33%

8 TRIUMPH OTDM-to-WDM conversion update14-December-2006

CONFIDENTIAL

Switched pulse - different settings

Pcontrol=16dBm

10dB>30dB

13%

24%Pcontrol=16dBm

~5dB~25dB

D@1550=0ps/nm/km

D@1550=-1ps/nm/kmPcontrol=19.5dBm

9 TRIUMPH OTDM-to-WDM conversion update14-December-2006

CONFIDENTIAL

Conclusion

We have studied the NOLM switch characteristics varying the dispersion of the HNLF.Trade off between minimum pulse distortion/maximum switching efficiency (lower dispersion to minimize the walk-off) and maximum WDM crosstalk (higher dispersion).Are peak pulse fluctuations and pulse distortions major issues for the OTDM to WDM conversion?Equipment involved: NOLM, EAMs, HNLFs,…Possible alternative: Kerr switch