Making Networks Light March 29, 2018 Charleston, South Carolina

Outline Rationale Efficiency Basic Components Key Innovations Multiplexing Trends

Rationale- Basis of Competition Performance. Reliability. Convenience. Price. From Christensen Innovators Dilemma

Internet Use Trends

Rationale for Optical Approach RUDIMENTARY COMPARISON (Miller, Proc. IEEE 97(7) 2009) Line Capacitance -vs- Detector Capacitance ELECTRICAL CONNECTIONS Must charge a line to the voltage of the link: Energy  (1/2) (Capacitance) (Voltage)2 OPTICAL CONNECTIONS Since we use photons and detectors, we use signaling voltage: Energy  (Photon Energy in eV)(Detector Capacitance) (Voltage) OPTICAL SIGNAL TRANSMISSION TAKES LESS ENERGY: Governed by photodetector capacitance. Optical signals are not subject to resistive line loss.

Efficiency- present emphasis Efficiency is measured by the user, and can be optimized for a just few metrics at once. SYSTEM METRICS: Acquisition Cost… Performance Manufacturability Compliance Reliability Maintainability Life Cycle Cost… NETWORK METRICS: Cost Physical Size Capacity Bandwidth Latency Protocols Management & Control

Fundamental Optical Link SOURCE- Typical 850 nm LED @ 100 Mb, 1 pJ per bit Typical 1500 nm DWDM Laser, 10 fJ per bit * MEDIA- Free space, optical waveguide, or optical fiber (< 1 dB per km) DETECTOR- Typical photodetector, fJ per bit MODULATOR- Typical modulator, when used, 1 pJ per bit

The Link Value Equation (2 x OEO + Optical Cable) < Electrical Cable

Common Optical Fiber MULTIMODE FIBER SINGLE MODE FIBER Outer Diameter 125 m Core Diameter 50, 62.5,…m Core Diameter 5-10 m Alignment Tolerance 10 m Alignment Tolerance 1 m Multiplexing ≤ 10 channels Multiplexing ≥ 200 channels Signal Bandwidth ≤ 10 GHz Signal Bandwidth ≥ 100 GHz Wavelength 850, 1300 nm Wavelength 1310-1650 nm

Common Passive Component

Laser Diode

Fiber Optic Modulator

Optical Amplifier (EDFA)

Modulation Formats Amplitude Modulation (analog / RF) RZ- Return to Zero, ON/OFF NRZ- Non-Return to Zero, Light on Phase Modulation- Phase Shift Keying (PSK) QPSK- Quadrature Phase Shift Keying Polarization Modulation Frequency Modulation (analog / RF) Pulse Amplitude Modulation (PAM) Practical systems to 64 QAM have been produced (6 bits per symbol), but QPSK (2 bits per symbol) is popular. PAM 4 is 3X more efficient than NRZ.

Key Innovations Low Loss Optical Fiber / Waveguide Semiconductor Laser High Speed Photodetector High Frequency Modulators Wavelength Division Multiplexing Optical Amplifiers Temperature Control Dispersion Compensation and Management Tunable Filters Vertical Cavity Surface Emitting Laser (VCSEL) Large Mode Field Fiber III-V Integration for Active Devices Wavelength Converters Silicon Photonics, Silica / SOI Photonics Ribbon Cable and Multi-Fiber Connectors Optical Data Storage and Computational Devices

Integration

Multiplexing More independent channels in a single fiber- Optical Code Division Multiplexing (OCDMA) Time Division Multiplexing (TDM) Wavelength Division Multiplexing (WDM) Space Division Multiplexing (SDM) Multi-Core Optical Fiber Ribbon Optical Fiber

WDM WAVELENGTH DIVISION MULTIPLEXING - Hundreds of channels per fiber. Standard wavelengths defined by ITU. Technology established for telecommunications. Transparent optical backbone. Five Optical Network Element (ONE) types perform all functions within the Optical Backbone Network: (OXC) Optical Cross-Connect (OPS) Optical Power Splitter (OADM) Optical Add/Drop MUX (OTM) Optical Terminal MUX (OLA) Optical Line Amplifier From: Stark, Habiby- Penn State EOC WDM LAN Functional Analysis Project 2008

Trends- Hardware Functions

Trend- Quantum Encryption From BBVA-OpenMind

Non Electrical Topside (NET) Corrosion is a significant issue for electrical systems in ships. Optical fiber is compatible with composite materials. Optical fiber transmission needs no ground. Optical fiber does not produce EMI. Optical fiber can be used for: Digital data transmission. Analog / RF signal transmission. Power delivery <100 watt. Illumination- LED / laser. Free space communication.

Thank you! John Mazurowski Penn State University Applied Research Laboratory Electro-Optics Center jsm23@arl.psu.edu 724-295-7000 x7139