Monolithically integrated multichannel SiGe/Si p-i-n-HBTphotoreceiver arrays

A low-power, short-wavelength eight-channel monolithically integrated photoreceiver array, based on SiGe/Si heterojunction bipolar transistors, is demonstrated. The photoreceiver consists of a photodiode, three-stage transimpedance amplifier, and passive elements for feedback, biasing and impedance matching. The photodiode and transistors are grown by molecular beam epitaxy in a single step. The p-i-n photodiode exhibits a responsivity of 0.3A/W and a bandwidth of 0.8 GHz at λ=0.88 μm. The three-stage transimpedance amplifier demonstrates a transimpedance gain of 43 dBΩ and a -3 dB bandwidth of 5.5 GHz. A single channel monolithically integrated photoreceiver consumes a power of 6 mW and demonstrates an optical bandwidth of 0.8 GHz. Eight-channel photoreceiver arrays are designed for massively parallel applications where low power dissipation and low crosstalk are required. The array is on a 250-μm pitch and can be easily scaled to much higher density. Large signal operation up to 1 Gb/s is achieved with crosstalk less than -26 dB. A scheme for time-to-space division multiplexing is proposed and demonstrated with the photoreceiver array     

GaAs optoelectronic integrated receiver array exhibiting high-speed response and little crosstalk

The letter focuses on the measurement of speed and crosstalk characteristics of a photoreceiver array which is composed of metal-semiconductor-metal (MSM) photodiodes and metal-semiconductor field-effect transistors (MESFETs) monolithically integrated on a semi-insulating (SI) GaAs substrate. We have obtained excellent eye diagrams at 2 Gbit/s, NRZ, and little crosstalk between nearest-neighbour channels of ?27 dB at 1.2 GHz.     

37-GHz bandwidth monolithically integrated InP HBT/evanescently coupled photodiode

In this letter, we demonstrate a monolithically integrated optoelectronic integrated circuit (OEIC) for 1.55-/spl mu/m wavelength application. The presented OEIC consists of an evanescently coupled photodiode (ECPD) and a single-stage common-base InP-InGaAs heterojunction bipolar transistor (HBT) amplifier. The guide structure was grown first by metal-organic chemical vapor deposition and pin/HBT was then regrown by molecular beam epitaxy. The ECPD exhibits a responsivity of 0.3 A/W and a -3-dB electrical bandwidth of 30 GHz. The photoreceiver demonstrates a -3-dB electrical bandwidth of 37 GHz with a transimpedance gain of 32 dB/spl middot//spl Omega/. This is, to our knowledge, the first ECPD/HBT ever reported for a monolithically integrated OEIC.     

7.1 GHz bandwidth monolithically integratedIn0.53Ga0.47As/In0.52Al0.48As PIN-HBT transimpedance photoreceiver

A monolithically integrated photoreceiver using an InAlAs/InGaAs HBT-based transimpedance amplifier has been fabricated and characterized. The p-i-n photodiode is implemented using the base-collector junction of the HBT. The 5 μm×5 μm emitter area transistors have self-aligned base metal and non-alloyed Ti/Pt/Au contacts. Discrete transistors demonstrated f_T and f_max of 54 GHz and 51 GHz, respectively. The amplifier demonstrated a -3 dB transimpedance bandwidth of 10 GHz and a gain of 40 dBΩ. The integrated photoreceiver with a 10 μm×10 μm p-i-n photodiode showed a -3 dB bandwidth of 7.1 GHz     

Monolithically integrated four-channel receiver array using diffused InGaAs (JFET technology)

Four-channel receiver arrays have been fabricated by monolithically integrating diffused InGaAs JFET-based electronics with InGaAs pin photodiodes. Cascode and simple inverter transimpedance amplifier circuits have been produced, both of which use a micro-FET as a tunable feedback element to vary bandwidth between 20 and 800 MHz. A sensitivity of -28.2 dBm was achieved at 1.25 Gbit/s with crosstalk between adjacent channels of -50 dB (electrical).<>     

Ultra-wideband monolithic photoreceivers using HBT-compatible HPTswith novel base circuits, and simultaneously integrated with an HBTamplifier

This paper presents two kinds of monolithically integrated ultra-wideband photoreceivers that use HBT-compatible HPTs with novel base circuits. The HPT photoreceiver, which consists of an HPT with an inductor and series resistor base circuit, yields ultra-broadband operation with 3 dB bandwidth from 0.43-12.1 GHz and over 11 dB gain compared to a photodiode with identical quantum efficiency. The HPT/HBT photoreceiver, which consists of an HPT with an inductor at the base terminal followed by an HBT amplifier circuit, yields ultra-wideband operation from 8.5-20.5 GHz (bandwidth of 12 GHz) with over 20 dB gain. The bandwidths of these photoreceivers are state-of-the art for monolithically integrated photoreceivers using HPT/HBT structures. The proposed photoreceivers, which are based on mature MMIC technologies, offer several other remarkable features such as good design accuracy and extremely small chip size     

Monolithically integrated InP-based front-end photoreceivers

The performance characteristics of a monolithically integrated front-end photoreceiver, consisting of a photodiode and a MODFET amplifier, were analyzed and measured. A vertical scheme of integration was initially used to realize a photoreceiver circuit on InP consisting of an InGaAs p-i-n diode, an InGaAs/InAlAs pseudomorphic MODFET, and passive circuit elements. The device structures were grown by single-step molecular beam epitaxy with an isolating layer in between. The microwave performance of 1-μm-gate MODFETs in the circuit is characterized by f_T=9 GHz, although identical discrete devices have f_T=30-35 GHz. The degradation is due to additional parasitic capacitances present in this integration scheme. In spite of this disadvantage the bandwidth of the circuit is 2.1 GHz. Integration of the p-i-n diode with 1.0- and 0.25-μm-gate MODFETs has also been done in a planar scheme using regrowth, and receiver bandwidths of 6.5 GHz were measured. This value is comparable to that of hybrid circuits with InP-based devices     

A 622 Mb/s monolithically integrated InGaAs/InP four-channel p-i-nFET receiver array

The authors describe the sensitivity and crosstalk characteristics of a long-wavelength monolithically integrated four-channel photoreceiver array. This receiver consists of 4 p-i-n PDs, 24 JFETs, and 28 level-shift diodes. The device is fabricated using MOVPE-grown crystals and a Be ion implantation technique. The receiver chip demonstrates a sensitivity of between -30.6 and -31.4 dBm, and crosstalk below -20 dB over its operating frequency range. Sensitivity deterioration due to crosstalk is demonstrated and is shown to be a critical factor in system performance. The crosstalk is mainly due to parasitic inductances on the external power supply circuits     

Design, modeling, and characterization of monolithically integratedInP-based (1.55 μm) high-speed (24 Gb/s) p-i-n/HBT front-endphotoreceivers

High-speed, long-wavelength InAlAs/InGaAs OEIC photoreceivers based on a p-i-n/HBT shared layer integration scheme have been designed, fabricated and characterized. The p-i-n photodiodes, formed with the 6000 Å-thick InGaAs precollector layer of the HBT as the absorbing layer, exhibited a responsivity of ~0.4 A/W and a -3 dB optical bandwidth larger than 20 GHz at λ=1.55 μm. The fabricated three-stage transimpedance amplifier with a feedback resistor of 550 Ω demonstrated a transimpedance gain of 46 dBΩ and a -3 dB bandwidth of 20 GHz. The monolithically integrated photoreceiver with a 83 μm p-i-n photodiode consumed a small dc power of 35 mW and demonstrated a measured -3 dB optical bandwidth of 19.5 GHz, which is the highest reported to date for an InAlAs/InGaAs integrated front-end photoreceiver. The OEIC photoreceiver also has a measured input optical dynamic range of 20 dB. The performance of individual devices and integrated circuits was also investigated through detailed CAD-based analysis and characterization. Transient simulations, based on a HSPICE circuit model and previous measurements of eye diagrams for a NRZ 2³¹-1 pseudorandom binary sequence (PRBS), show that the OEIC photoreceiver is capable of operation up to 24 Gb/s     

11 GHz ultrawide-bandwidth monolithic photoreceiver using InGaAspin PD and InAlAs/InGaAs HEMTs

A very-wide-bandwidth long-wavelength monolithically integrated photoreceiver is presented which comprises an InGaAs pin PD and a transimpedance amplifier. The receiver uses epilayers grown by one-step MOVPE. The InGaAs channel high-electron-mobility field effect transistor (HEMT) employs an Si planar-doped carrier supplying layer to obtain larger transconductance and uniform threshold voltage. The 0.5 μm gate length is used for HEMTs to enhance the speed of operation. This receiver shows a very wide bandwidth of 11 GHz, and opened eye for a 15 Gbit/s NRZ signal. This is the first demonstration of a long-wavelength monolithic photoreceiver receiving a 15 Gbit/s light signal     

Modulator driver and photoreceiver for 20 Gb/s optic-fiber links

Two integrated circuits, a modulator driver and a photoreceiver integrating a metal-semiconductor-metal (MSM) photodetector, a differential transimpedance amplifier and two limiting amplifier stages for high-speed optical-fiber links are presented. The IC's were manufactured in a 0.2 μm gate-length AlGaAs-GaAs high-electron mobility transistor (HEMT) technology with a f_T of 60 GHz. The modulator driver IC operates up to 25 Gb/s with an output voltage swing of 3.3 V_p-p at each output. The 1.3-1.55 μm wavelength monolithically integrated photoreceiver optoelectronic integrated circuit (OEIC) has a bandwidth of 17 GHz with a high transimpedance gain of 12 kΩ. Eye diagrams are demonstrated at 20 Gb/s with an output voltage of 1 V_p.p     

Crosstalk investigation of laser-diode pairs

The crosstalk between the lasers of different laser-diode pairs has been investigated experimentally in the frequency domain. The mutual crosstalk of two lasers diodes monolithically integrated on a single transmitter chip and separated by 100 μm was measured to be about -50 dB up to a modulation frequency of 100 MHz. At higher frequencies, it rises linearly with the frequency to -40 dB at 1 GHz. Measurements and calculations indicate that the origin of this crosstalk is the leakage current in the chip and inductive coupling of the bond wires. With these crosstalk values, digital data transmission at high bit rates is possible without significantly reducing the receiver sensitivity     

8-element linear array monolithic p-i-n MODFET photoreceivers usingmolecular beam epitaxial regrowth

An 8-element linear array of single-stage integrating front-end photoreceivers using molecular beam epitaxial (MBE) regrowth was investigated. Each element consisted of a p-i-n In_0.53Ga_0.47As photodiode integrated with a selectively regrown pseudomorphic In_0.65Ga_0.35As/In_0.52Al_0.48 As MODFET. Cutoff frequencies of 1.0-μm discrete regrown MODFETs were f_t=24 GHz and f_max=50 GHz. Transconductance of the regrown MODFETs was as high as 495 mS/mm with a current density (I_ds) of 250 mA/mm. The 3-dB bandwidth of the photoreceiver was measured to be 1 GHz. The bit rate sensitivity at 1 Gb/s was -31.8 dBm for BER 10^-9 using 1.55 μm excitation for a photoreceiver with an anti-reflection coating. The single-stage amplifier exhibited up to 25 dB flatband gain of the photocurrent, and a two-stage amplifier was up to 31 dB of gain. Good uniformity between each photoreceiver element in the array was achieved. Electrical crosstalk between photoreceiver elements was estimated to be ~-34 dB     

Monolithically integrated, photoreceiver with large, gain-bandwidth product

A direct-detection 800 nm GaAs monolithically integrated photoreceiver is reported with a photocurrent gain of 200 and a 1 GHz bandwidth capable of driving a 50 ? load with IV peak pulses. The integrated NPN photodiode has over 7GHz bandwidth and requires no modifications to the ion-implanted GaAs MESFET process. The 200GHz gain-bandwidth product and 3200 V/W responsivity are among the highest reported for similar receivers.     

High isolation, planar filters using EBG substrates

The concept of electromagnetic bandgaps (EBGs) has been utilized to develop a high-quality filter that can be integrated monolithically with other components due to a reduced height, planar design. Coupling adjacent defect elements in a periodic lattice creates a filter characterized by its ease of fabrication, high-Q performance, high-port isolation, and integrability to planar or 3-D circuit architectures. The filter proof of concept has been demonstrated in a metallo-dielectric lattice. The measured and simulated results of 2-, 3-, and 6-pole filters are presented at 10.7 GHz     

Eight-channel p-i-n/HBT monolithic receiver array at 2.5 Gb/s perchannel for WDM applications

We report a monolithic chip incorporating an eight channel p-i-n/HBT photoreceiver array designed for multichannel WDM applications. The p-i-n photodetectors are edge illuminated and centered at a 250 μm pitch for mating with either ribbon fiber connectors or waveguide demultiplexers. Each channel operates at 2.5 Gb/s with an electrical crosstalk of -20 dB between adjacent channels. The average sensitivity of each receiver in the array was measured to be (-20±1) dBm for a bit error rate of 10^-9 at a wavelength of 1.5 μm     

Monolithically integrated long wavelength photoreceiver OEIC based on InP/InGaAs HBT technology

The epitaxial structure and growth, circuit design, fabrication process and characterization are described for the photoreceiver opto-electronic integrated circuit (OEIC) based on the InP/lnGaAs HBT/PIN photodetector integration scheme. A 1.55 μm wavelength monolithically integrated photoreceiver OEIC is demonstrated with self-aligned InP/lnGaAs heterojunction bipolar transistor (HBT) process. The InP/lnGaAs HBT with a 2 μm × 8 μm emitter showed a DC gain of 40, a DC gain cutoff frequency of 45 GHz and a maximum frequency of oscillation of 54 GHz. The integrated InGaAs photodetector exhibited a responsivity of 0.45 AAV at λ = 1.55 μm, a dark current less than 10 nA at a bias of -5 V and a -3 dB bandwidth of 10.6 GHz. Clear and opening eye diagrams were obtained for an NRZ 223-l pseudorandom code at both 2.5 and 3.0 Gbit/s. The sensitivity for a bit error ratio of 10-9 at 2.5 Gbit/s is less than -15.2 dBm.     

A 3 GHz transimpedance OEIC receiver for 1.3-1.55 μm fiber-opticsystems

A high-performance metal-semiconductor-metal high-electron-mobility transistor (MSM-HEMT) transimpedance photoreceiver fabricated using OMCVD-grown InAlAs/InGaAs heterostructures on an InP substrate is discussed. This is the first demonstration of a monolithically integrated receiver amplifier that incorporates a cascode amplifier stage and a Schottky diode level-shifting stage implemented on InP-based optoelectronic integrated circuit (OEIC) photoreceivers. The transimpedance amplifier has an open-loop gain of 5.7 and a bandwidth of 3.0 GHz, which represent the highest gain and the highest speed performance reported for 1.3-1.55-μm-wavelength OEIC receivers     

A new photoreceiver concept using InGaAs-transferred-electrondevices

A new optical receiver is proposed incorporating an InGaAs-transferred-electron device with Schottky gate-electrode (STED) and an InGaAs-metal-semiconductor-metal detector (MSM). This photoreceiver is applicable to the detection of digital, intensity modulated signals and can be integrated on an InP-substrate. The monolithically integrated circuit has been fabricated. Both the integrated STED and the MSM detector has been characterized. From the measurements the receiver can be expected to offer high current gain and inherent pulse shaping. Based on experiments the sensitivity and the gain of the photoreceiver as a function of the bit-rate has been calculated     

Low-loss phased-array based 4-channel wavelength demultiplexerintegrated with photodetectors

A 4-channel phased-array wavelength division demultiplexer with 1.8 nm channel spacing at 1.54 μm has been monolithically integrated with photodetectors in InP/InGaAsP. On chip losses are 3.5 to 4.5 dB. These are the lowest losses reported so far for demultiplexers monolithically integrated with photodetectors. Nearest neighbor crosstalk ranges from -12 to -21 dB