No abstract

In current telecommunications systems, there is a strong need to increase the data rate. The next generation of optical communication systems will operate at 40 Gb/s. As high-speed receivers for such systems, monolithic photoreceiver OEICs are very attractive, because of their potential for lower parasitics and higher performances compared to hybrid approaches. We report here the monolithic integration of a InP[Zn]/GaInAshP[Si] PIN photodiode with GaInAshP composite channel HEMTs. The PIN-HEMT structure is grown by single-step LP-MOVPE on pre-recessed semi-insulating InP substrate. This quasi-planar integration scheme allows a standard microelectronics processing. The O.1pm T-shape HEMT gates are defined by e-beam lithography, as close as 70pm to the 3pm deep photodiode pockets. As a preliminary result, a 4-channel receiver OEIC has photodiodes with 0.8 A/W responsivity, 30nA dark current at -1OV, two-stage amplifiers with 20 to 28 dB gain and a bandwith of 3GHz.

No abstract

The design, fabrication and characteristics of a coplanar distributed ultra broadband amplifier are presented. The circuit is fabricated using a composite channel InP CC-HEMT high breakdown voltage technology with developed in Alcatel OPTO+. It exhibits an average gain of 13dB over a 92 GHz -3dB cut-off frequency that corresponds to a state of the art gain-bandwidth product of 410 GHz for baseband amplifier IC's. It still presents 8 dB gain at 110 GHz Such an amplifier is a good candidate for 40 and 80Gbit/s optoelectronic driver modules applications. We will discuss the use of coplanar wave-guide lines and low impedance bias micro-stnp transmission lines in such a design. We will also highlight the need of largest bandwidths for 40 Gbit/s eye diagram quality and the needed gain-bandwidth product for 80 Gbith ETDM communications.variation to get the same penalty as for 10 Gbit/s systems [5]. We present a broadband amplifier that will be useful for both 40 Gbit/s improved quality transmissions and 80 Gbit/s applications. The 13 dB broadband gain is the typically required value for driver module building blocks [6]. In this paper, we present the design, fabrication and measurements of a travelling wave amplifier based on 0.1 ym gate length InP composite channel High Electron Mobility Transistor (CC-HEMT) suitable for 40 Gbit/s high quality transmissions and future 80 Gbit/s bit rates.In a first part we give an overview of the technology used. Then the circuit structure and its specific electric and layout design aspects are reviewed. Experimental results, are given with comments on the needed bandwidth for 80 Gbit/s transmissions and specific D.C characteristics of the coplanar designs. Device Fabrication I. IntroductionIn fibre communication systems, high bit rates are obtained using two complementary methods : Dense Wavelength Division Multiplexing (DWDM) combined with high bit rate (40 Gbit/s per wavelength) Electrical Time Division Multiplexing (ETDM) [1][2][3]that allows global bit rate over 1 Tbit/s 141. In this configuration, the transmission quality strongly depends on the front-end circuits . The modulator driver is the most critical circuit because it operates at the maximum bit rate while requiring both high gain and output voltages. Distributed amplifier IC's are widely used as broadband gain building blocks in high speed transmission systems. The high performance required now for 43 Gbit/s long haul systems directly implies wider bandwidth amplifiers to get low system penalty. The bit error rate as a global transmission quality parameter is the final optimisation value. Even through transmissions at 43 Gbith have already been demonstrated, it is still necessary to improve signal waveform by transmitting higher harmonics and achieving very low group delay 0-7803-7447-9/02/$17.0002002 IEEE The chip is fabricated with an InGaAsAnP HEMT technology developed at OPTO+ [7]. All layers are grown by MOVPE process. The high breakdown voltage is obtained by using a double channel structure (GaInAs, InP) and a thi...