ICE 541 Concrete Mathematics Design of OPSy (Optical Packet Synchronizer) Kim jinah Gang kwanwook

ICE 541 Concrete Mathematics  What is OPSy (Optical Packet Synchronizer) ? In an asynchronous optical network system, each transmitter node sends out optical packets asynchronously. The electric control systems for switching these packets at an optical packet switching node(OPSw) are much simpler when incoming packets are aligned in a series of common time slots provided at the OPSw. This alignment call, which is also called packet synchronization, is a key technology for the development of OPSw, and it achieved using an optical packet synchronizers (OPSy). Introduction

ICE 541 Concrete Mathematics coupler 2x2 Switch Signal(1550nm) circulator High dispersive fiber WC DFB LD (1540nm) WC DFB LD (1550nm) coupler 2x2 Switch Signal(1550nm) circulator High dispersive fiber WC DFB LD (1560nm) WC DFB LD (1550nm) Ch 1 Ch 2 2R regeneration Fiber Delay Loop Proposed Sync. system

ICE 541 Concrete Mathematics  Characteristics of Fiber Delay Loop Advantages - Flexible system : possible to control delay following loop times, otherwise use fixed delay line in other system Disadvantages - It needs two switches and delay lines per one channel : generate crosstalk and signal degradation : use amplifier to compensation - Total latency is high (determine latency following loop numbers) : total times to rotation of signal(ns-us), switching times(~ms) Proposed Sync. system

ICE 541 Concrete Mathematics  How’s it proceed Packet signal generation : Random packet generation >> Examine packets : Sorting algorithm >> Delay : If_else statement >> Circulation : For Loop >> pass Loop >>analysis of results (NW socket programing under UNIX circumstance using C++ compiler)  Conditions for Sync. System - How many channel is efficient to satisfy high speed? - Proper range of using wavelength range under physical Fiber Delay Loop - Proper fiber loop length - How many times circulate fiber Loop to align packet synchronously Sync. system algorithm

ICE 541 Concrete Mathematics Sync. system condition  Time slot & packet format  Time slot : 1024ns  Packet length : 896ns  Guard time : 128ns Time slot (1024ns) Packet length (896ns) Gurad time (128ns) IEEE Photonic Technology Letter. Sep. 2002

ICE 541 Concrete Mathematics Sync. system algorithm  Misalignment of packet Ch 1 Ch 2 Ch 3 Ch n …… ∆t 1 ∆t n

ICE 541 Concrete Mathematics Sync. system condition  DCF condition & Delay - DCF condition : Dispersion : -90ps/nm km : Dispersion slope : 0.21ps/nm 2 km - Delay with optical channel (f 0 = 193.1THz) ChannelDelay(ps)ChannelDelay(ps)

ICE 541 Concrete Mathematics Sync. system algorithm  Wavelength selection  If ∆tn is larger than the half of packet length (448ns) Accelerate signal THz ~ THz  If ∆tn is smaller than the half of packet length (448ns) Delay signal THz ~ THz  Packet divided by signal channel (the # of f n ) 56ns 112ns168ns224ns280ns336ns392ns448ns 0ns f0f0 f1f1 f2f2 f3f3 f4f4 f5f5 f6f6 f7f7

ICE 541 Concrete Mathematics  System specification  Time resolution : the half of packet / # of signal channel / 2 Ex) 448ns/8/2 = 28ns  # of loop circulation : time segment / channel delay Ex) 56ns/ ~360ps =  Bit rate independent Sync. system algorithm

ICE 541 Concrete Mathematics Future works  Program for optimization  DCF condition : Dispersion per length, dispersion slope etc(signal degradation).  Wavelength conversion : Channel spacing, channel range, # of channel etc.  Determine optimized system factor : : # of ch, Loop length, delay time following wavelength. Others…