Andreas G. Steffan

Millimeter-Wave Photonic Components for Broadband Wireless Systems

We report on advanced millimeter-wave (mm-wave) photonic components for broadband radio transmission. We have developed self-pulsating 60-GHz range quantum-dash Fabry-Perot mode-locked laser diodes (MLLD) for passive, i.e., unlocked, photonic mm-wave generation with comparably low-phase noise level of -76 dBc/Hz @ 100-kHz offset from a 58.8-GHz carrier. We further report on high-frequency 1.55-μm waveguide photodiodes (PD) with partially p-doped absorber for broadband operation (f3dB ~70-110 GHz) and peak output power levels up to +4.5 dBm @ 110 GHz as well as wideband antenna integrated photomixers for operation within 30-300 GHz and peak output power levels of -11 dBm @ 100 GHz and 6-mA photocurrent. We further present compact 60-GHz wireless transmitter and receiver modules for wireless transmission of uncompressed 1080p (2.97 Gb/s) HDTV signals utilizing the developed MLLD and mm-wave PD. Error-free (BER = 10-9, 231 - 1 PRBS, NRZ) outdoor wireless transmission of 3 Gb/s over 25 m is demonstrated, as well as wireless transmission of uncompressed HDTV signals in the 60-GHz band. Finally, an advanced 60-GHz photonic wireless system offering record data throughputs and spectral efficiencies is presented. For the first time, we demonstrate photonic wireless transmission of data throughputs up to 27.04 Gb/s (EVM 17.6%) using a 16-QAM OFDM modulation format resulting in a spectral efficiency as high as 3.86 b/s/Hz. Wireless experiments were carried out within the regulated 57-64-GHz band in a lab environment with a maximum transmit power of - 1 dBm and 23 dBi gain antennas for a wireless span of 2.5 m. This span can be extended to some 100 m when using high-gain antennas and higher transmit power levels.

60 GHz radio-over-fiber technologies for broadband wireless services [Invited]

Some of the work carried out within the European integrated project Integrated Photonic mm-Wave Functions for Broadband Connectivity (IPHOBAC) on the development of photonic components and radio-over-fiber technologies for broadband wireless communication is reviewed. In detail, 60 GHz outdoor radio systems for >10 Gbits/s and 60 GHz indoor wireless systems offering >1 Gbit/s wireless transmission speeds are reported. The wireless transmission of uncompressed high-definition TV signals using the 60 GHz band is also demonstrated.

Cascaded modulator architecture for WDM applications

Integration density, channel scalability, low switching energy and low insertion loss are the major prerequisites for on-chip WDM systems. A number of device geometries have already been demonstrated that fulfill these criteria, at least in part, but combining all of the requirements is still a difficult challenge. Here, we propose and demonstrate a novel architecture consisting of an array of photonic crystal modulators connected by a dielectric bus waveguide. The device architecture features very high scalability and the modulators operate with an AC energy consumption of less than 1fJ/bit. Furthermore, we demonstrate cascadeability and multichannel operation by using a comb laser as the source that simultaneously drives 5 channels.

High-Power and High-Linearity Photodetector Modules for Microwave Photonic Applications

We demonstrate hermetically packaged InGaAs/InP photodetector modules for high performance microwave photonic applications. The devices employ an advanced photodiode epitaxial layer known as the modified uni-traveling carrier photodiode (MUTC-PD) with superior performance in terms of output power and saturation. To further improve the thermal limitations, the MUTC-PDs were flip-chip bonded on high thermal conductivity substrates such as Aluminum Nitride (AlN) and Diamond. Modules using chips with active area diameters of 40, 28, and 20 μm were developed. The modules demonstrated a 3-dB bandwidth ranging from 17 GHz up to 30 GHz. In continuous wave mode of operation, very high RF output power was achieved with 25 dBm at 10 GHz, 22 dBm at 20 GHz, and 17 dBm at 30 GHz. In addition, the linearity of the modules was characterized by using the third order intercept point (OIP3) as a figure of merit. Very high values of OIP3 were obtained with 30 dBm at 10 GHz, 25 dBm at 20 GHz and more than 20 dBm at 30 GHz. Under short pulse illumination conditions and by selectively filtering the 10 GHz frequency component only, a saturated power of >21 dBm was also measured. A very low AM-to-PM conversion coefficient was measured, making the modules highly suitable for integration in photonic systems for ultralow phase noise RF signal generation.

Hybrid integrated 40 Gb/s DPSK receiver on SOI

A DPSK receiver using a flip-chip hybrid of InP photodetectors on SOI boards with waveguide delay line interferometer and SOA preamplifier on SOI boards are developed. The horizontal waveguide integration enables bandwidths exceeding 40 GHz.

Novel E-Band (71–76 GHz) photodiode module featuring a hermetic grounded-coplanar-waveguide-to-rectangular-waveguide transition

This paper presents a novel concept of a hermetic E-Band Photodiode (PD) Transmitting Module for Radio-over-Fiber (RoF) applications. A commercial PD chip with 50 Ω coplanar waveguide (CPW) output is wire-bonded to a 50 Ω grounded coplanar waveguide (GCPW) based on ROGERS RT/Duroid 5880 substrate. From the GCPW board a hermetic transition that makes use of a double-slot coupling approach is designed and optimized for the 71–76 GHz band. This concept allows to efficiently coupling the electrical power delivered by the PD chip to a Rectangular Waveguide WR-12 output with an insertion loss of only 3 dB.

ETDM Transmitter Module for 100-Gb/s Ethernet

Performance of a packaged distributed-feedback travelling-wave electroabsorption modulator module for data transmission at 100 Gb/s is presented for the first time. Clearly open eye diagrams at 80 Gb/s with an extinction ratio (ER) of 4.9 dB and 100 Gb/s with ER 4.2 dB (limited by measurement setup) are demonstrated together with data transmission over 100-m-long standard single-mode fiber and over dispersion-compensated 10-km fiber link.

100 Gb/s ETDM Transmitter Module

Components of a 100 Gb/s transmitter with electrical time-division multiplexing are presented as following: electrical multiplexer, driver amplifier, and large-bandwidth distributed feedback-traveling-wave electro-absorption modulator module. The performance of the parts of the transmitter, as well as the complete chain, is investigated for data operation and transmission in future 100 Gb/s Ethernet (100GbE). Clearly open eye diagrams at 100 Gb/s are demonstrated together with data transmission over 300 m long standard single mode fiber link.

Hybrid-Integrated Polarization Diverse Coherent Receiver Based on Polymer PLC

A dual-polarization coherent receiver using polymer planar lightwave circuit technology is demonstrated for the first time. It comprises optical 90 hybrids on the basis of polymer waveguides, polarization beam-splitting thin-film elements, and photodetectors made of InGaAsP/InP. The chip size fits into the existing receiver package standards. The receiver assembly shows a high polarization extinction ratio (>;25 dB over C-band) and is successfully operated in system experiments with 16-quadrature-amplitude modulation and quadrature phase-shift keying modulation up to 112 Gb/s.

Dual-quadrature coherent receiver for 100G Ethernet applications based on polymer planar lightwave circuit

A novel dual-quadrature coherent receiver based on a polymer planar lightwave circuit is presented. The packaged receiver is successfully operated in 112 Gb/s DP-QPSK transmission experiments showing only 1.3 dB penalty compared to theory.