Microwave Photonics

Microwave Photonics Photonics techniques for generation, transmission, processing of microwave signals

Why photonics techniques

Microwave Photonic Link (Radio on Fiber Link)

INPUT µW

SIGNALS

OUTPUT µW

SIGNALS

OPTICAL FIBER

OPTICAL SOURCE

PHOTO - DETECTOR

• Fiber can be better than coaxial cable

• New functionalities

Fiber Coax - Size 0.25 mm 2-6 mm - Weight 0.073 g/m 30~100 g/m - Loss(dB/km) 0.4~0.8 1000~1500 - Time-Bandwidth Product >106 102

Advantage of Fiber over Coaxial Cable

Application: Mobile Communication Networks

Established Cell

RemoteAntenna Unit

Central Station

Example of Fiber Radio system for closed-area shopping mall (Japan)

Tennjinnbashisuji Shopping Mall (Osaka) Base Station

Topology : Star Number of base units: 2, access units: 9 Fiber length: Approx. 2000 m/2 systems

Courtesy of NTT DoCoMo

Optics fiber (DoCoMo)

Fixed telephone lines (NTT)

Apporox. 50m To another arcade

Courtesy of NTT DoCoMo

Tennjinnbashisuji Shopping Mall Base Station

RoF in the Building

• World Trade Center in Japan (very high building)

Topology:Star Number of base units: 2, access units: 15 Fiber length: Approx. 1200 m/2 systems

Antenna

Courtesy of NTT DoCoMo

Radio-on-Fiber for Closed Area Mobile Services

Optical fiber

Shadow of building

In-building

Underground shopping mall

Antenna base

station

Central Office

Satellite communication

To other building

Household Antenna

base station

► High transmission loss of millimeter-wave - Many antenna base stations - Many closed-area (no service area) ► Radio-on-fiber systems

Broadband Wireless Access

CARRIER FREQ.: Millimeter Waves FCC opened 70, 80 and 90GHz bands for commercial uses (2004/10) Millimeter-wave generation and processing are required

Broadband fixed backbone

network

fiber

Military Applications – (1)

Fiber : flexible, small and light, no EMI Communication Network Radar Systems – Phased Array Antennas

Military Applications – (2)

Fiber : flexible, small and light, no EMI Communication and Radar Systems in Planes and Tanks Inter-Connection between Complex Control Systems

Atacama Large Millimeter Array (ALMA)

ALMA : study the structure of the early universe and the evolution of galaxies The array consists of 64 telescopes with 12-meter dish antennas Location : high-altitude (5000 meters), extremely dry mountain site in Chile's Atacama desert for free from distortions caused by atmospheric water

Construction Sight of ALMA

Photonics in ALMA

A Simple Picture for Fiber Radio Link

µwave to baseband

light to µwave

µwave to light

Requirements • Generation of microwave photonic signals • Transmission of microwave photonic signals • Detection of microwave photonic signal

Important Parameters for Fiber Radio System

Digital Optical Communication Transporting Bits. Bit rate Data Recovery

Bit Error Ratio Eye Opening, Q

Sensitivity (for BER=10-9) Jitter Intersymbol Interference Power penalties

Dispersion, Chirp Reflections, Channel Crosstalk Nonlinearities Error-Free Transmission

Fiber Radio System Transporting and Storing Signals Bandwidth Dynamic Range

Spurious Free Dynamic Range Compression Dynamic Range

Signal-to-Noise Ratio Noise Figure Phase Noise Intermodulation Distortion Power Penalties

Dispersion, Chirp Reflections, Channel Crosstalk Nonlinearities

Output Power High-Fidelity Transmission