Millimeter- and submillimeter-wave integrated circuits (MMICs and S-MMICs) and modules developed at the Fraunhofer IAF for manifold applications in the frequency range up to 700 GHz are presented. These circuits use the advanced metamorphic high electron mobility transistor (mHEMT) technology based on the InAlAs/InGaAs material system on 4" GaAs substrates. The presented circuits are key components in wireless communication systems, sensor systems, as well as radio astronomic receivers.

Two compact H-band (220–325 GHz) low-noise millimeter-wave monolithic integrated circuit (MMIC) amplifiers have been developed, based on a grounded coplanar waveguide (GCPW) technology utilizing 50 and 35 nm metamorphic high electron mobility transistors (mHEMTs). For low-loss packaging of the circuits, a set of waveguide-to-microstrip transitions has been realized on 50-μm-thick GaAs substrates demonstrating an insertion loss of <0.5 dB at 243 GHz. By applying the 50 nm gate-length process, a four-stage cascode amplifier module achieved a small-signal gain of 30.6 dB at 243 GHz and more than 28 dB in the bandwidth from 218 to 280 GHz. A second amplifier module, based on the 35-nm mHEMT technology, demonstrated a considerably improved gain of 34.6 dB at 243 GHz and more than 32 dB between 210 and 280 GHz. At the operating frequency, the two broadband low-noise amplifier modules achieved a room temperature noise figure of 5.6 dB (50 nm) and 5.0 dB (35 nm), respectively.

In this paper, we present the development of an ultra-broadband H-band (220 - 325 GHz) submillimeter-wave monolithic integrated circuit (S-MMIC) medium power amplifier (MPA) module for use in next generation high-resolution imaging systems and communication links operating around 300 GHz. Therefore, a variety of compact amplifier circuits has been developed by using an advanced 35 nm InAlAs/InGaAs based depletion-type metamorphic high electron mobility transistor (mHEMT) technology in combination with grounded coplanar waveguide (GCPW) circuit topology. A three-stage amplifier S-MMIC based on compact cascode devices was realized, demonstrating a maximum gain of 22.2 dB at 294 GHz and a small-signal gain of more than 16 dB over the frequency range from 184 to 312 GHz. Finally, mounting and packaging of the monolithic amplifier chip into a WR-3.4 waveguide module was accomplished with only minor reduction in circuit performance.

A compact WR-1.5 (500-750 GHz) low-noise amplifier (LNA) circuit has been developed, based on a grounded coplanar waveguide (GCPW) technology utilizing 20 nm metamorphic high electron mobility transistors (mHEMTs). The realized six-stage LNA TMIC achieved a maximum gain of 15.4 dB at 576 GHz and more than 10 dB in the frequency range from 555 to 619 GHz. For low-loss packaging of the circuit, a waveguide-to-microstrip transition has been fabricated on a 20 ¼m thick GaAs substrate, demonstrating an insertion loss of only 1 dB between 500 and 720 GHz. The realized LNA module achieved a small-signal gain of 14.1 dB at 600 GHz and a room temperature (T = 293 K) noise figure of 15 dB at the frequency of operation.

A 200 GHz power amplifier is presented. The millimeter-wave monolithic integrated circuit (MMIC) has been realized in a 35 nm InAlAs/InGaAs cascode metamorphic high electron mobility transistor (MHEMT) process in grounded coplanar waveguide technology (GCPW). The amplifier demonstrates an output power of 14 mW with 11.4 dB compressed power gain at 200 GHz. This represents an increase in output power in comparison to previous reported MHEMT-based MMIC amplifiers. The small-signal gain demonstrates a peak value of 20 dB and is above 15.9 dB from 185 to 215 GHz.

A compact H-band (220-325 GHz) low-noise amplifier circuit has been developed, based on a grounded coplanar waveguide (GCPW) technology utilizing 50 nm metamorphic high electron mobility transistors (mHEMTs). The realized four-stage cascode LNA achieved a small-signal gain of 31 dB at 243 GHz and more than 28 dB in the frequency range from 218 to 280 GHz. Coplanar topology in combination with cascode transistors resulted in a very compact die size of only 0.5 × 1.5 mm2. For low-loss packaging of the circuit, a set of waveguide-to-microstrip transitions has been realized on 50 μm thick GaAs substrates demonstrating an insertion loss of less than 0.5 dB at 243 GHz. The realized LNA module achieved a small-signal gain of 30.6 dB and a room temperature (T = 293 K) noise figure of 5.6 dB at the frequency of operation.

A balanced amplifier has been designed and fabricated. The monolithic millimeter-wave integrated circuit (MMIC) has been realized in a 35-nm InAlAs/InGaAs metamorphic high electron mobility transistor (mHEMT) process in grounded coplanar waveguide (GCPW) technology. It demonstrates a measured small-signal gain better than 19 dB between 180 and 200 GHz. The measured saturated output power achieves a maximum value of 10.2 dBm between 180 and 190 GHz.

For use in a millimeter-wave direct detection radiometer for earth remote sensing, we have developed a low-noise amplifier (LNA) module with a small-signal gain of 19.5 dB at 243 GHz and a 3 dB bandwidth of 40 GHz. The implemented three-stage LNA MMIC has been manufactured using a 50 nm gate length metamorphic HEMT (mHEMT) technology on 50 m thick GaAs substrates. Each of the two on-chip integrated E-plane probe waveguide transitions offers a transmission loss of only 0.5 dB at 243 GHz including a 7.5 mm long WR-3.4 waveguide. Due to the low-loss packaging, the LNA module achieves a low noise figure of only 6.0 dB at room temperature.

For the next generation of sensors and communication systems operating at frequencies up to 600 GHz and above, the Fraunhofer IAF is developing a broad variety of millimeter-wave and terahertz monolithic integrated circuits (MMICs and TMICs) and modules. The monolithic integrated circuits are realized using the advanced metamorphic high electron mobility transistor (mHEMT) technology in the InGaAs/InAlAs material system on 4" GaAs substrates. The potential of this technology is demonstrated in this paper by two TMICs operating at 600 GHz: a high-gain amplifier and an active frequency multiplier-by-six.

In 2010, the standard for 100GbE was approved, which specifies the transmission of 100 Gb/s via 4 wavelength channels of 25 Gb/s each. A solution based on a 100 Gb/s single wavelength channel is capable of significant cost reductions should the required components be available. Within the HECTO project, we developed components suitable for single-wavelength 100 Gb/s transmission. In this article, the project is described - its organization, objectives, possible impacts, and results - including the successful demonstration in a final field trial. A complete ETDM system utilizing the monolithically integrated transmitter and receiver modules developed in the project was built to transmit 112 Gb/s over 42 km standard single-mode fiber. Finally, we attempt an outlook on the prospective development of Ethernet standardization beyond 100GbE.

In this paper, we report on the development of a microstrip-to-waveguide transition for the WR-1.5 waveguide band (500-750 GHz). The microstrip lines and E-plane probes have been manufactured on 25 μm thick GaAs substrates. The transmission loss per single microstrip-to-waveguide transition is only 1.0 dB @ 670 GHz. The measured return losses are better than 10 dB up to 720 GHz. The single transition includes a waveguide section with a length of 7.0 mm corresponding to the transitions which will be used in future submillimeter-wave MMIC modules.

In this paper, we present the development and characterization of an H-band (220 - 325 GHz) low-noise amplifier MMIC, realized in metamorphic HEMT technology with a gate length of 35 nm. The active devices in the realized three-stage LNA are common-source and common-gate transistors connected in cascode configuration. The LNA circuit achieves a linear gain of 26.3 dB with a 3-dB-bandwidth from 218 to 260 GHz. The measured noise figure of the LNA is 6.1 dB in the frequency range around 243 GHz.

Traditional intensity modulated two-level electrical time-division multiplexing（ETDM）transmission systems working at 100-112Gbit/s were investigated.The complete ETDM systems based on monolithically integrated transmitter and receiver modules were demonstrated with bit-error-rate（BER）performance of 10-8 at 107Gbit/s,and near error-free standard forward error correction（FEC）threshold（2×10-3）at 112Gbit/s.The experiment results showed that directly modulated high-speed ETDM transmission systems with the symbol rates at 100Gbaud and beyond were promising candidate for cost-effective 100GbE applications and might be a preform of the next generation of Terabit/s Ethernet.

It is now clear that 112-Gb/s data rate is the next step in the network evolution (100-Gb/s Ethernet). Due to its high speed and high breakdown voltage, the InP double-heterojunction bipolar transistor (DHBT) technology is particularly suited for signal processing and high-speed communication systems. This paper summarizes our InP DHBT device and integrated circuit (IC) technology developed for >; 100-Gb/s-class medium scale mixed-signal ICs. Key features and issues important for the growth and manufacturing of InP DHBTs with step-graded collectors are first discussed. The molecular-beam-epitaxy-grown transistors have cut-off frequencies (f T and f max ) of over 350 GHz, current gains of ~90, and common-emitter breakdown voltages of >; 4.5 V. Using this technology, we then fabricated and succeeded in 112-Gb/s testing of multiplexers and integrated clock and data recovery/1:2 demultiplexer ICs and modules with very clear eye waveforms. Using the same technology, a distributed amplifier intended for use as a modulator driver exhibited an output voltage swing of ~2 V pp . These building-block ICs combine high-speed operation with high signal quality and enable 112-Gb/s optical fiber transmission.

In this paper, we present the development of submillimeter-wave monolithic integrated circuits (S-MMICs) and modules for use in next-generation sensors and high-data-rate wireless communication systems, operating in the 300-500-GHz frequency regime. A four-stage 460-GHz amplifier MMIC and a 440-GHz class-B frequency doubler circuit have been successfully realized using our 35-nm InAlAs/InGaAs-based metamorphic high-electron mobility transistor (mHEMT) technology in combination with grounded coplanar circuit topology (GCPW). Additionally, a 500-GHz amplifier MMIC was fabricated using a more advanced 20-nm mHEMT technology. To package the submillimeter-wave circuits, a set of waveguide-to-microstrip transitions has been fabricated on both 50-μm-thick quartz and GaAs substrates, covering the frequency range between 220 and 500 GHz. The E-plane probes were integrated in a four-stage 20-nm cascode amplifier circuit to realize a full H -band (220 to 325 GHz) S-MMIC amplifier module with monolithically integrated waveguide transitions.

Key components and architecture options are being actively investigated to realize next generation transport technology in optical networks. Serial transmission systems using a single wavelength have, so far, provided cost effective solutions and therefore remain desirable. For 100 Gbit/s Ethernet, this option will, however, depend on the availability of the electronic and optical components. Due to its high speed and high breakdown voltage, the InP double-heterojunction bipolar transistor (DHBT) technology is particularly suited for signal processing and high-speed communication systems. This contribution describes our InP DHBT based integrated circuit (IC) technology developed for 100 Gbit/s class mixed-signal ICs. Using this technology, we fabricated and succeeded in 112 Gbit/s testing of key electronic components, including a multiplexer (MUX), a distributed amplifier, and an integrated clock and data recovery (CDR)/1:2 demultiplexer (DEMUX), with very clear eye waveforms. These high-speed building block ICs are described and the main results are presented.

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.

A high-speed pin-TWA photoreceiver, comprising a photodiode and a travelling-wave amplifier, monolithically integrated on a single InP chip, are characterized in OOK system experiments. Error-free performance below the FEC limit is achieved in back-to-back measurements up to 112 Gb/s.

A compact H-band (220-325 GHz) submillimeter-wave monolithic integrated circuit (S-MMIC) amplifier has been developed, based on a grounded coplanar waveguide (GCPW) technology utilizing 50 nm and 35 nm metamorphic high electron mobility transistors (mHEMTs). By applying the 35 nm gate-length process, a four-stage cascode amplifier circuit achieved a small-signal gain of 26 dB at 320 GHz and more than 20 dB in the bandwidth from 220 to 320 GHz. Based on the 50 nm mHEMT technology, the same amplifier design demonstrated a linear gain of 19.5 dB at 320 GHz and more than 15 dB between 240 and 320 GHz. Coplanar topology in combination with cascode transistors resulted in a very compact die size of only 0.6 mm2. For low-loss packaging of the circuit, a set of waveguide-to-microstrip transitions has been realized on 50 μm thick GaAs and quartz substrates demonstrating an insertion loss S21 of less than 2 dB and 1.25 dB at 320 GHz, respectively. Finally, successful mounting and packaging of the amplifier chip into an H-band waveguide module was accomplished with only minor reduction in performance.