Nikolai Fediakine

SI/PI work for co-packaging of switch die and optics

• Developed procedure for port de-embedding, correlation with AFR SW of Keysight. • Design of flex circuitries for RF and power/control applications • Measurement in lab with VNA/LCA: O-E and E-O for coherent receivers and I-Q dual polarization modulators, automation of measurements • RF design for CFP2/OSFP-ACO-64G-64QAM and characterization/verification. • Design of high-density high-speed client/line sides for 1.2T DSP module.

• SI integrity, RF design and characterization CFP4, QSFP28, SFP+ and CFP2 ACO • Characterization of CWDM TOSA 28G: EO bandwidth, electrical RL and correlations with mask margin measurements. • ESD protection for RF lines and verification for TSFP+ transceivers. • System level RF simulations for QSFP-DD-64GB-PAM4: power budget, PAM4 eye diagram, BER performance

• Designed linear 28Gbps O2E for 850nm, developed technology for manufacturing: PCB with cavities, die attach, wire bond. • Testing & characterization of 28G O2E: frequency, linearity, temperature, EMI. • Developed technique for OE/EO measurements using flash laser and laser beating

• Designed 100G EO and OE subsystems: MZ modulator, coherent Rx • Post –layout simulations of SI for 32Gbps and 10G using AnsoftLink and HFSS • Characterization of RF interconnects for 100G test board: s-parameters, TDR, gated measurements and correlations with HFSS simulations. • Designed RF part of boards for 40G/100G test platforms, choice of geometry /type transmission lines, laminate, finishing and stack up. • Simulated and designed loop control algorithm for I/Q deskew in optical DQPSK modulators for 40/100G applications. • System simulations of 100G communication channel with electrical interconnects, nonlinear driver amplifiers and optical imperfections. • Designed ASIC for 100G PM-QPSK: CD equalization, RF path and analysis of PDN

• Designed technique of Power Delivery Network for BGA package seen from the silicon side based on correlations and simulations. • Studied FPGA I/O timing variations (push-out, pull-in, and jitter) due to SSO noise. Model included package and PCB. Model correlated with measurements. • Compared susceptibility FEXT and NEXT in different packages (flip-chip, wire-bond and number of layers) generated on selected victims from aggressors. • Simulated signal quality (eye diagram, jitter etc), caused by x-talks, SSN and real package degradation for different applications: DDR3 (800Mb/s), SGMII (1.25 GB/s) Package model included bump, traces, via transitions, balls and PTH.

• Designed FPGA to control via I2C bus settings of tunable DWDM laser for long haul applications. • Leaded design of hot pluggable line card for 10Gb/s DWDM/WDM long haul applications. Responsibility for framer, transmitter and receiver parts. • Designed 11.1 Gb/s WDM transmitter based on TOSA for 80km applications. Developed procedure of calibration, including sets of operating point, output power, wavelength, temperature. Dispersion penalty- power budget optimization. Measurement of chirps of EML lasers at 10 GB/s. • Designed HV for APD and power monitoring (40dB range) for 11.1 GB/s APD ROSA. Developed adjustment algorithm with temp and BE variations. • Work on fast performance monitoring (PM) algorithms, based on FEC engine. • Designed linear and PWM TEC control circuits to perform thermal management of EML. Designed bias circuits for different configurations of laser: LD and PD cathodes grounded, LD cathode and PD anode grounded etc. • Designed 8 channel CWDM 1GE/FC system for long haul applications. Realized Fiber Channel Open Fiber Control (OFC) algorithm for safety compliance. • Designed, prototyped, tested and transferred to manufacture 1310nm /1490nm bidirectional gigabit transceiver in GBIC format for point-to-point applications up to 70km. Power budget was 24dB in the full temperature range 0-70C. • Prototyped bi-di GBIC for EPON applications: transmitter (ONU) switching ON/Off time < 100ns and receiver (OLT) recovery time < 400ns. • Designed and implemented optical bi-directional transceivers in SFP and 1x9 formats 1.25Gb/s data rate, single SM fiber support, single receptacle connector, distance up to 70km, 0-70C, x-talks <-30dB.