1. Clock recovery by FP-FBGs –How things shape up? e source line width is narrower than the resonator bandwidth. Optical Clock Recovery with Fabry-Perot Filter Based on Fiber Bragg Gratings Nandu VS 1,VT Gopakumar 2, V P Mahadevan Pillai 1, Madhusoodhanan 3, Balaji Srinivasan 4 1.Department of Optoelectronics, University of Kerala 2.VKCET,Dept of ECE,Parippally,Kerala,3.Department of Instrumentation,CUSAT,Kerala4.Department of Electrical Engineering IIT Madras, Chennai, email:vtgopakumar111@gmail.com. Theory of clock recovery by FP-FBGs Abstract Fabry-Perot filters based on fiber Bragg gratings are widely used as optical narrowband filters and as sensors. Here we propose and demonstrate all optical clock recovery with Fabry-Perot filters made up of fiber Bragg gratings. Motivation All optical signal processing, System synchronization, All optical timing extraction. FP-FBG Fabrication Schematic Simulation results Conclusions So far complex methods are used for all optical clock recovery, here we described a simple in fiber and very stable passive optical clock recovery circuit. Above proposed Optical clock recovery circuits will be highly useful for optical signal processing system, such as all optical regenerative repeaters, all optical time division switching systems, and all optical de-multiplexers. Acknowledgement I would like to thank my good old student Mrs.Ranju Aziz, (Faculty, Dept.of Opto Electronics, Kerala University) and Mr.Prshanth,(MS Scholar of ESD @IITm) for their valuable help during the initial stage and measurement stage respectively. FBG Writing Set up and characterization @ESD,IITm FP-FBG Fabricated @ FBG writing facility @ ESD, IITm One of the pass bands of FP-FBGs is designed and fabricated to the center frequency of the incoming optical data stream. The The FSR of the FP-FPG is equal to data clock frequency The source line width is narrower than the resonator bandwidth. Only the line spectral components, which contain the carrier frequency fo and the timing components fo±B are transmitted, this results in optical continuous timing clock extraction. Continuous spectral components of RZ optical data Line spectral components Bit rate FSR Optical Spectrum of extracted Optical clock FP-FBG filter Pass Bands Excimer Laser@248 nm Cylindrical lens Phase Mask Holder Fiber Holder Fiber translational stage Light wave Measurement System Tunable laser Power Meter Network cable FP-FBG L δLδL δL=10mm L=3mm FSR=10.58G neff=1.43Hz (Photline MX-LN) δL=10mm L=3mm PIN PD+TIA Tunable laser Source 10Gbps PRBS Generator Optical intensity Modulator FP-FBG Polarization controller Optical Receiver ESA The FSR of the FP-FPG is equal to data clock frequency We got the FSR of 10.58GGz @ an effective cavity length of 10mm. We are trying to increase the cavity length so as to get the FSR of 10GHz,by holding the FP-FBG tightly in the fiber holder and paste it to a stick or by a Piezo-Electric resonator and characterize it again. We are also trying to write another FP-FBG with δL=10.484 mm long so as to get the FSR of 10GHz exactly to recover the clock. Grating fabrication Real time simulation software Optical Spectrum @10Gbps, 2 31 -1 PRBS RZ Power extinction of line Spectral component to Cont. Spectrum>50dB Recovered clock@ 10GHz (not scaled) FP-FBG Spectrum Effective cavity Length δL=10mm FBG Length L=3mm λ B=1550.8nm R=95% Power Extinction>30dB Clock recovery simulation results FP-FBG Experimental Set up for Optical clock recovery