conference & convention enabling the next generation of networks & services Oral Session THU 3A Equipment & Component Technologies: Optical Communications Extremely Long-span Non Extremely Long span Non-repeatered repeatered Submarine Cable Systems & Submarine Cable Systems & Related Technologies & Equipment Related Technologies & Equipment 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
conference & convention enabling the next generation of networks & services 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
conference & convention enabling the next generation of networks & services Non-Repeatered Submarine Cable Systems Total Length < approx 450 km Total Length < approx 450 km SLTM SLTM SDH SDH O O MUX MUX W W SLTM SLTM D D M M E E F F IP IP Router Router SLTM SLTM LTE LTE STM-64 / STM-64 / STM-16 STM-16 Signal Signal Level Level Fibre Loss Fibre Loss Distance Distance ▐ Main Features ▐ Main Applications ● No active elements in transmission line ● Island to Island ● No power feeding required ● Mainland to Island ● Lower system cost compared to ● Festoon repeatered systems
conference & convention enabling the next generation of networks & services Key Technologies for Expanding Non-repeatered Systems Span ▐ Maximizing Signal Power to Fiber ● Suppression of Stimulated Brillouin Scattering ● Non-linear tolerant modulation format ● Novel Fiber (Larger core fiber, Lower non-linearity) ● 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
conference & convention enabling the next generation of networks & services Submarine Line Terminal Equipment SLR320SW LTE SLTM WME ▐ 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 ● +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
conference & convention enabling the next generation of networks & services Key Tech.(1): DRA / IRPA (Backward Pumping) ▐ OSNR improvement by relaxation of signal power loss ▐ Effective reduction of launched signal power to the fiber (Low Non-linearity) DRA IRPA Signal Signal Pump Pump Station A Station B Station A Station B EDF ( Tx ) ( Rx ) ( Tx ) ( Rx ) ~100km DRA w/o IRPA w/o Signal Signal DRA Gain Pump Pump DRA IRPA Level Level Source Source Gain Gain w/ w/ IRPA DRA OSNR Improvement
conference & convention enabling the next generation of networks & services Key Tech.(1): DRA / IRPA (Backward Pumping) tem Gain [dB] 25 1000mW Pumping IRPA 20 DRA: 8dB 15 IRPA: 19dB 10 DRA System 2000mW Pumping 2000mW Pumping 5 DRA: 10~11dB 0 IRPA: 21~22dB 0 500 1000 1500 2000 Pump Power [mW] � 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.
conference & convention enabling the next generation of networks & services Key Tech.(2): DRA (Forward Pumping) Signal ▐ Improvement factors by DRA with Pump Station A Station B forward pumping are dependent on ( Tx ) ( Rx ) DRA Gain the balance of signal power and Pump Source w/ DRA pump power. Signal ▐ Level diagram design is essential to Level w/o DRA w/o DRA maximizing the span length. OSNR Improvement (w/o nonlinearity) Actual System Gain (w/ nonlinearity) OSNR Improvement [dB] 25 25 +9dBm +9dBm +12dBm System Gain [dB] 20 20 +12dBm +15dBm 15 15 +18dBm +15dBm 10 10 Total +18dBm 5 Signal power 5 0 0 0 500 1000 1500 2000 2500 0 500 1000 1500 2000 2500 Pump Power [mW] Pump Power [mW]
conference & convention enabling the next generation of networks & services Key Tech.(3): RZ-DPSK Modulation ▐ Receiver sensitivity Improvement of approx. 2.5dB ▐ High quality transmission against dispersion-related non-linear degradation ▐ High tolerance for Stimulated Brillouin Scattering Receiver sensitivity 10 -2 10Gb/s RZ-DPSK Transmitter 10Gb/s RZ-DPSK Transmitter NRZ NRZ RZ 10GHz Pre-coder Clock 10 -3 RZ-DPSK 10Gb/s-Data LD DPSK-mod RZ-mod 10 -4 2.5dB Improvement 10 -5 BER 10Gb/s DPSK Receiver 10 -6 10 -7 CDR Balanced DPSK DMUX Receiver Demodulator 10 -8 10 -9 10 -10 10 -11 10 -12 -46 -44 -42 -40 -38 -36 -34 -32 Pre AMP Input Power (dBm)
conference & convention enabling the next generation of networks & services 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+00 1.0E-01 1.0E-02 1.0E-02 w/o FEC w/o FEC w/o FEC w/o FEC 1.0E-03 1.0E-04 1.0E-05 Output BER 1.0E-06 RS(255,239) RS(255,239) RS(255,239) RS(255,239) 1.0E-07 Hyper Ex Ex Ex Ex 1.0E-08 FEC A-FEC A-FEC A-FEC A-FEC 1.0E-09 1.0E-10 A-FEC A-FEC A-FEC A-FEC A-FEC 1.0E-11 1.0E-12 1.0E-05 1.0E-04 1.0E-03 1.0E-02 1.0E-01 Input BER
conference & convention enabling the next generation of networks & services Applicable Range of SLR320SW Applied Technologies Transmission w/o DRA With DRA With DRA + IRPA Capacity w/o IRPA ( Gb/s) 640 320 160 80 Distance 200 300 400 500 ( km) � SLR320SW achieves the system gain as high as 85 dB for 10Gb/s x 16WDM system. (approx. 450km)
conference & convention enabling the next generation of networks & services 40Gb/s Non-repeatered System ▐ 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 ● 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
conference & convention enabling the next generation of networks & services 40Gb/s Transponder ▐ Main Features 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 STM-256/OC-768, STM-64/OC-192, 10GbE LAN PHY Tunable Dispersion Compensation Module (TDCM) � 4x40Gb/s SLTMs in one SLT shelf � 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 RZ-DPSK RZ-DPSK RZ-DPSK Modulation format RZ-DQPSK RZ-DQPSK RZ-DQPSK
conference & convention enabling the next generation of networks & services 40Gb/s Performance Receiver sensitivity (Back-to-back) Non-linear power penalty 5 10 -2 4 10 -3 penalty [dB] 40Gb/s 10 -4 3 RZ-DPSK BER 10Gb/s 10 -5 RZ-DPSK RZ-DPSK 2 2 10 -6 10 Q pe 10Gb/s 10 -7 40Gb/s 10 -8 RZ-DPSK 1 10 -9 RZ-DPSK 10 -10 10 -11 10 -12 0 10 11 12 13 14 15 16 17 18 19 -48 -46 -44 -42 -40 -38 -36 -34 -32 -30 -28 Pre AMP Input Power (dBm) Fiber Input Power (dBm/ch) ▐ 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.
conference & convention enabling the next generation of networks & services Applicable Range for 40Gb/s Systems Transmission Transmission Transmission Transmission Applied Technologies Capacity Capacity Capacity Capacity w/o DRA With DRA With DRA + IRPA ( ( Gb/s ( ( Gb/s Gb/s) Gb/s ) ) ) w/o IRPA 1280 1280 1280 1280 640 640 640 640 320 320 320 320 200 300 400 500 Distance ( km) � 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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