Bandwidth-Flexible CDC ROADMs Massimo Di Blasio, Director, Carrier Business Development. Market Focus ECOC 2011

Transcription

1 Bandwidth-Flexible CDC ROADMs Massimo Di Blasio, Director, Carrier Business Development Market Focus ECOC 2011

2 Topics Being Presented Where are ROADMs today and how did we get here? Flexgrid : What are they and how do they work? Next generation ROADMs: More than just a 2

3 Optical Transport Network Evolution - Connectivity 1. Transition from SONET/SDH to IP Networks 2. Continual increase in transmission speeds 3. Fiber moving closer to customer (e.g. FTTH, Mobile Backhaul) 4. Connectivity evolving from Point-to-Point to Mesh Interconnected Rings Point-to-Point Interconnected Rings Mesh 3

4 Network Evolution - Spectral Efficiency System capacity now constrained by spectral efficiency (non-linear Shannon limit) Source: Essiambre et al, JLT,

5 Future Network Requirements Heterogeneous network traffic Alphabet soup of modulation formats OOK/DPSK/DQPSK/DP-QPSK/DP-OOFDM/DP-mPSK Network potentially needs to support up to two orders of magnitude variation in bit-rate 10/40/100/400/1000 Gb/sec Non-intrusive parallel multiport optical channel monitoring More than 4 ports Match transport channel capacity to router port capacity (40/100GbE) Future ROADMs need to maximize network flexibility while being virtually invisible 5

6 But what really matters is 5 Year Growth (Sources: Cisco, Verizon) Carrier Revenue Growth (6.6% per annum) Data Usage Growth (38% per annum) Drives operational efficiencies (OPEX reduction) in carriers and rapid adoption of more costeffective technologies, such as: IP Everywhere match pipe sizes 4G/LTE for mobile ROADMs & coherent transmission for optical transport 6

7 Current Degree 8 ROADM Colored Add/Drop 1 9x1 2 9x1 Monitor Ingress and Egress signals with Optical Channel Monitors (OCM) Output Input 9x1 8 All Drop Wavelengths available, separation by AWGs AWG AWG AWG Add Wavelengths aggregated by passive combiners Broadcast & Select 7

8 Evolution of the Optical Add/Drop Node CDCF* Technological Complexity (up to 20D) Flexgrid (up to 8-D) PLC-based 2D ROADM Wavelength Blocker Fixed Optical Add/Drop (Thin Film/Grating/AWG) * CDCF = Colourless, Directionless, Contentionless, Flexgrid, Confidential 8

9 Switching: Matrix versus Channelised First Generation allocated a single channel to a single pixel (e.g. MEMS, LC, etc) Second Generation use matrix-based switching LC/MEMS LCoS Phase (LCoS) 8 bit Angle (DLP) 2 bit 9

10 Flexgrid and LCoS: Ultimate Flexibility Ability to set ROADM channel bandwidth and centre frequency to optimize system performance Match channel bandwidth to signal bandwidth Pack them as closely together as possible LCoS provides the ultimate flexibility and allows left and right edges of channels, as well as centre frequency, to be trimmed independently Arbitrary Bandwidth, Centre Frequency 12.5 GHz as trade-off between OS complexity, flexibility, performance Support dual channel plan or full flexgrid Rel IL (db) -2.5 Rel IL (db) Rel Freq (GHz) Rel Freq (GHz) 10

11 Flexgrid Implementation for ITU G GHz as trade-off between Network OSS complexity, flexibility, performance Allows for full compliance with ITU G down to 25 GHz channel spacing 11

12 DWP9f 12.5 GHz Flexgrid Performance

13 Announced Flexible Bandwidth Company Technology Slice Width CoAdna Liquid Crystal 25 GHz Finisar LCoS 12.5 GHz Nistica DLP MEMS Array 25 GHz Oclaro Liquid Crystal 25 GHz Santec* LCoS JDSU LCoS * Santec product is a 4x4 OXC, rather than a true 1xN 13

14 Flexgrid 8D ROADM; Passive Drop, Active Add 1 16x1 Flex 2 16x1 Flex 16x1 Flex 8 1x23 Flex Demux 1x23 Flex Demux 1x23 Flex Demux OCM must be Flexgrid compatible 14

15 What is CDCF? CDCF = Colorless, Directionless, Contentionless, Flexgrid Current ROADMs provide ability to provision core network paths remotely, but still require manual patching of transceivers to set Add/Drop directionality Next generation of ROADMs will be designed to (finally) to do away with the need for this May require changes to how are used to achieve performance required 15

16 CDCF ROADM: Back-to-Back x1 Flex 16x1 Flex x1 Flex 16x1 16x1 Flex Output Input 8 16x1 Flex Drop Mux/Demux Mux/Demux 16x1 Flex Add 16

17 Back-to-Back High Port Count High port count Flexgrid on both add and drop sides of core Shared with Mux and Demux Advantages Efficient flexible architecture that minimizes contention Reduces crosstalk requirements Compatible with multiple approaches for Add/Drop routing and switching Power budget efficient for reduced amplification requirements Disadvantage Doubles the number of filter passes in the core network however this is minimized with bandwidth enhancement 17

18 8x16/20/24/32 Mux/Demux Single Flexgrid Channel Add/Drop Asymmetric: transponder side port {1,..,20, 24, 32} can be assigned to at most one (reconfigurable) direction {1,..,8} From OK Mux/Demux OK NOT SUPPORTED 1 32 To Transponders 18

19 8xN MCS Options Possible Architectures using multi-cast switch (MCS) Key Issue is the IL of the MCS and the TFA MCS with EDFAs & Tunable Filter Array MCS with EDFA Array MCS with Single EDFA per direction 19

20 Mux/Demux vs. MCS Key drivers to technology selection Cost When comparing the MCS to the programmable Mux Demux, you need to evaluate the complete financial solution MCS + EDFA Array versus Mux/Demux MCS + EDFA + TFs versus Mux/Demux TF = Tunable Filter Port Count > 16 ports, IL becomes an issue for MCS CDC Add-Drop Port Expansion More than 16 ports 24, 32, 40, 48 ports Modulation Format Coherent Vs. Non Coherent Channel Flexibility 20

21 Summary Flexgrid -capable ROADMs will be key subsystems for the next generation of optical networks Matrix-based switching elements (LCoS, DLP) provide most flexible platform for Flexgrid To achieve benefits of Flexgrid requires a whole ecosystem of Flexgrid-compatible components, as well as developments in Network OSS, not just 21

22 Bandwidth-Flexible CDC ROADMs Massimo Di Blasio, Director, Carrier Business Development Market Focus ECOC 2011