Extremely Long-span Non Extremely Long span Non-repeatered - - PowerPoint PPT Presentation

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Extremely Long Extremely Long-span Non span Non-repeatered repeatered Submarine Cable Systems & Submarine Cable Systems & Related Technologies & Equipment Related Technologies & Equipment

Oral Session THU 3A Equipment & Component Technologies: Optical Communications

Related Technologies & Equipment Related Technologies & Equipment

Yoshihisa Inada Yoshihisa Inada, Yoshitaka Kanno, Isao Matsuoka, , Yoshitaka Kanno, Isao Matsuoka, Takanori Inoue, Takehiro Nakano and Takaaki Ogata Takanori Inoue, Takehiro Nakano and Takaaki Ogata NEC Corporation NEC Corporation

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Outline

1. Introduction 2. Features of SLR320SW LTE and it’s key technologies

• DRA and IRPA with high power pumping light
• DRA and IRPA with high power pumping light
• RZ-DPSK modulation
• Hyper FEC

3. 40Gb/s non-repeatered systems 4. Summary

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Total Length < approx 450 km

LTE

Total Length < approx 450 km

LTE

Non-Repeatered Submarine Cable Systems

Signal Level Distance Fibre Loss Signal Level Distance Fibre Loss

▐ Main Features

• No active elements in transmission line
• No power feeding required
• Lower system cost compared to

repeatered systems

▐ Main Applications

• Island to Island
• Mainland to Island
• Festoon

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▐ Maximizing Signal Power to Fiber

• Suppression of Stimulated Brillouin Scattering
• Non-linear tolerant modulation format
• Novel Fiber (Larger core fiber, Lower non-linearity)

Key Technologies for Expanding Non-repeatered Systems Span

• Novel Fiber (Larger core fiber, Lower non-linearity)

▐ Improvement of Receiver Sensitivity

• Modulation format with high receiver sensitivity
• FEC technology advancement

▐ Mitigation of Signal Power Loss during Transmission

• Distributed Raman amplification / In-line Remote Pumping

Amplification

• Low loss fiber

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▐ Main Features

• High capacity with narrow channel spacing;

10Gb/s-33WDM with 100GHz channel spacing 10Gb/s-66WDM with 50GHz channel spacing

• +30dBm high power booster amplifier

Submarine Line Terminal Equipment SLR320SW LTE

SLTM WME

• +30dBm high power booster amplifier
• Distributed Raman Amplification (DRA) / In-Line

Remote Pumping Amplifier (IRPA)

• High power remote pumping source up to

2000mW

• Modulation Type: NRZ, RZ and RZ-DPSK
• Excellent Receiver Sensitivity with Advanced FEC
• Suppression of Stimulated Brillouin Scattering
• 10Gb/s Clear Channel Transmission
• Upgradeable up to 66 WDM signals without traffic

interruption

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Key Tech.(1): DRA / IRPA (Backward Pumping)

DRA IRPA ▐ OSNR improvement by relaxation of signal power loss ▐ Effective reduction of launched signal power to the fiber (Low Non-linearity)

Signal EDF Pump Signal Level IRPA Gain DRA Gain ~100km w/o IRPA w/ IRPA Station A ( Tx ) Station B ( Rx ) Pump Source Station A ( Tx ) Station B ( Rx ) Signal Pump Signal Level DRA Gain w/ DRA w/o DRA Pump Source

OSNR Improvement

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Key Tech.(1): DRA / IRPA (Backward Pumping)

10 15 20 25 tem Gain [dB]

IRPA DRA 1000mW Pumping DRA: 8dB IRPA: 19dB 2000mW Pumping

5 500 1000 1500 2000 Pump Power [mW] System

Higher pumping source achieves higher system gain. Non-linear effect and multiple Rayleigh Scattering effect induced by extremely high pump power should be carefully assessed. 2000mW Pumping DRA: 10~11dB IRPA: 21~22dB

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Key Tech.(2): DRA (Forward Pumping)

Signal Pump Signal Level w/ DRA w/o DRA Station A ( Tx ) Station B ( Rx ) DRA Gain Pump Source

▐ Improvement factors by DRA with forward pumping are dependent on the balance of signal power and pump power. ▐ Level diagram design is essential to

5 10 15 20 25 500 1000 1500 2000 2500 Pump Power [mW] System Gain [dB]

5 10 15 20 25 500 1000 1500 2000 2500 Pump Power [mW] OSNR Improvement [dB]

w/o DRA

+9dBm +12dBm +15dBm +18dBm

Actual System Gain (w/ nonlinearity)

+9dBm +12dBm +15dBm +18dBm

OSNR Improvement (w/o nonlinearity)

maximizing the span length.

Total Signal power

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10-2

NRZ

Receiver sensitivity

Key Tech.(3): RZ-DPSK Modulation

10Gb/s RZ-DPSK Transmitter

▐ Receiver sensitivity Improvement of approx. 2.5dB ▐ High quality transmission against dispersion-related non-linear degradation ▐ High tolerance for Stimulated Brillouin Scattering

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10-3 10-12 10-11 10-10 10-9 10-8 10-7 10-6 10-5 10-4

Pre AMP Input Power (dBm) BER NRZ RZ RZ-DPSK

2.5dB Improvement

LD DPSK-mod RZ-mod 10GHz Clock

10Gb/s RZ-DPSK Transmitter

10Gb/s-Data Pre-coder Balanced Receiver DPSK Demodulator CDR DMUX

10Gb/s DPSK Receiver

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1.0E-02 1.0E-01 1.0E+00

Key Tech.(4): Hyper FEC

▐ FEC coding gain at BER=10-13 : 10dB ▐ 1.5dB improvement against our current A-FEC in terms of Q value

1.0E-12 1.0E-11 1.0E-10 1.0E-09 1.0E-08 1.0E-07 1.0E-06 1.0E-05 1.0E-04 1.0E-03 1.0E-02 1.0E-05 1.0E-04 1.0E-03 1.0E-02 1.0E-01

w/o FEC w/o FEC w/o FEC w/o FEC RS(255,239) RS(255,239) RS(255,239) RS(255,239) A-FEC A-FEC A-FEC A-FEC Ex Ex Ex Ex A-FEC A-FEC A-FEC A-FEC

Hyper FEC A-FEC

Input BER Output BER

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With DRA With DRA + IRPA w/o DRA w/o IRPA Applied Technologies Transmission Capacity ( Gb/s) 640 320

Applicable Range of SLR320SW

Distance ( km) 160 80 200 300 400 500

SLR320SW achieves the system gain as high as 85 dB for 10Gb/s x 16WDM system. (approx. 450km)

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▐ 40Gb/s system deployment is indispensable to meet the growing capacity demand for repeatered and non- repeatered submarine cable systems.

• Higher capacity capability (High spectral efficiency)
• Lower cost per bit

40Gb/s Non-repeatered System

• Lower cost per bit
• Reduction of power dissipation
• Equipment down-sizing (Reduction of footprint)
• Seamless connection between terrestrial 40Gb/s system

Experimental evaluation of performance difference between Experimental evaluation of performance difference between 10Gb/s and 40Gb/s non 10Gb/s and 40Gb/s non-repeatered submarine cable systems repeatered submarine cable systems

• Receiver sensitivity

Receiver sensitivity

• Non

Non-linear tolerance linear tolerance

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▐ Main Features

40Gb/s Transponder

• RZ-DPSK / RZ-DQPSK modulation formats
• Enhanced FEC codes
• Cover ITU-T grid with 100GHz/50GHz grid
• Various interfaces

STM-256/OC-768, STM-64/OC-192, 10GbE LAN PHY

40Gb/s Transponder Type SLTM40 SLTM40-Q SLTM40-XG Tributary Interface STM-256/OC-768 STM-64/OC-192 10GbE Line Bit Rate 43.02Gb/s 43.02Gb/s 44.57Gb/s FEC coding gain (BER=1x10-13) 8.2dB 8.2dB 8.2dB Modulation format RZ-DPSK RZ-DQPSK RZ-DPSK RZ-DQPSK RZ-DPSK RZ-DQPSK

STM-256/OC-768, STM-64/OC-192, 10GbE LAN PHY

• Tunable Dispersion Compensation Module (TDCM)
• 4x40Gb/s SLTMs in one SLT shelf

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40Gb/s Performance

Receiver sensitivity (Back-to-back) Non-linear power penalty

10-3 10-6 10-5 10-4 10-2

2 3 4 5

BER penalty [dB]

40Gb/s RZ-DPSK 10Gb/s RZ-DPSK

▐ Difference of receiver sensitivity is approximately 7dB. ▐ No remarkable difference in transmission impairment ▐ Performance difference between 10Gb/s systems and 40Gb/s systems is merely in receiver sensitivity.

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10-12 10-11 10-10 10-9 10-8 10-7 10

1 2 10 11 12 13 14 15 16 17 18 19

Q pe Pre AMP Input Power (dBm) Fiber Input Power (dBm/ch)

10Gb/s RZ-DPSK RZ-DPSK 40Gb/s RZ-DPSK

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Applicable Range for 40Gb/s Systems

With DRA With DRA + IRPA w/o DRA w/o IRPA Applied Technologies

Transmission Transmission Transmission Transmission Capacity Capacity Capacity Capacity ( ( ( ( Gb/s Gb/s Gb/s Gb/s) ) ) ) 1280 1280 1280 1280 640 640 640 640

Distance ( km)

320 320 320 320

200 300 400 500

Maximum capacity with 40Gb/s system can be increased by four times as that with 10Gb/s. Span length with 40Gb/s system is sacrificed only by the difference of RX sensitivity. Available System gain: 78dB for 16WDM case (approx. 420km)

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Summary

• Key technologies for our non-repeatered submarine terminal equipment

SLR320SW LTE have been introduced. – High power pump source for DRA and IRPA: upto 2000mW – RZ-DPSK modulation with high receiver sensitivity – High performance FEC Available system gain: 85dB for 10Gb/s 16WDM (~450km)

• 40Gb/s non-repeatered system is feasible over 400 km

Available system gain: 85dB for 10Gb/s 16WDM (~450km)

• Further R&D for 40Gb/s non-repeatered system is underway for longer

span length. Modulation format with higher Rx sensitivity and higher NL tolerance FEC technology with higher coding gain Mitigation of fiber non-linearity Available system gain: 78dB for 40Gb/s 16WDM (~420km)

2010

enabling the next generation of networks & services

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Pacifico Convention Plaza Yokohama & InterContinental The Grand Yokohama 11 ~ 14 May 2010 www.suboptic.org The 7th International Conference & Convention

• n Undersea Telecommunications