100 Tbit/s spectral-efficient Data Link Using Orbital Angular Momentum Multiplexing

H. Huang, G. Xie, Y. Yan, N. Ahmd, Y. Ren and A. E. Willner Optical Communication Lab, Ming Hsheh Department of Electrical Engineering, University of Southern Califoria

haoh@usc.edu, supported by Darpa Inpho program

Problem: Bandwidth demand > Spectral resource Existing Solutions

λ1 λ2 λ3

Freq.

WDM on multiple OAM modes

Data 1

Data 2

Data 3

Gaussian

Gaussian

Gaussian Gaussian

Data 123

Data 456

Data 789

Data 123

λ1

λ2

λ3

l1 l2 l3 OAM modes

OAM Phase

Transmitter array

Wavelength multiplexing

Convert Gaussian mode to OAM mode

OAM mode multiplexing

Receiver array Wavelength demultiplexing

Convert OAM mode to Gaussian mode

OAM mode demultiplexing

Propagation

Experimental results

0 100 200 300 400 50087654321

Channel Number

-log1

0(BE

R)

EFEC threshod

10

15

20

25

30

35

40

OSNR (dB)

500 600 700 800 900 100087654321

Channel Number

-log1

0(BE

R)

EFEC threshod

10

15

20

25

30

35

40

OSNR (dB)

BER

OSNR

BER

OSNR

FEC threshold FEC threshold

squeeze the channel spacing

Freq.

Freq.

Ch1 Ch2 Ch3

Ch1 Ch2 Ch3

Spectral resource is limited, even for optics.

(Tbit/s)

Loss

(dB

/km

)

Utilize advanced modulation formats

>60 Tbit/s capacity is needed by 2015.

Year

1 bit/symbol 2 bit/symbol 4 bit/symbol

Spectral efficiency is improved by 4 times, but we need more.

OAM l1

OAM l2

OAM l3

OAM l4

Multiplexing

SuperImposed OAMs

OAM l1

OAM l3

OAM l4 Data 1

Data 3

Data 2

Data 4 OAM l2

Intensity

Intensity

Data 1

Data 2

Data 3

Data 4

Demultiplexing

-4 -3 -2 -1 0 1 2 3

x 10-3

-4

-3

-2

-1

0

1

2

3

x 10-3

l = 0

(OAM = +1)

-4 -3 -2 -1 0 1 2 3

x 10-3

-4

-3

-2

-1

0

1

2

3

x 10-3

0100

200

300

400

500

600

0

0.5 1

1.5 2

2.5 3

x 1

05

0100

200

300

400

500

600

0 2 4 6 8

10

12

x 1

04

Non-OAM beam

-2

0

2

-2

0

2

OAM beam

Phase front Intensity profile

“Pasta spirals” Phase “Donut” Intensity

What is OAM How to generate OAM

Phase

OAM multiplexing/demultiplexing

Know

about OA

M

How to detect OAM

OAM is a new degree of freedom to improve the spectral efficiency and capacity

3 modes 6 modes 12 modes 24 modes

42 wavelengths

24 OAM modes

1008 independent channels

100 Gbit/s QPSK on each

channel

Spectral efficiency ×24

Total capaicty 100.8 Tbit/s

Achievements

Hao Huang et al., OFC2013, paper OTh4G.5