Monolithic balanced p-i-n/HBT photoreceiver for coherent optical heterodyne communications

Two InGaAs p-i-n photodetectors connected in a balanced configuration have been monolithically integrated with a transimpedance preamplifier made from InP-InGaAs heterojunction bipolar transistors (HBTs) to realize a balanced optoelectronic integrated circuit (OEIC) receiver. The receiver, with a bandwidth of 3 GHz and a common mode rejection of 25 dB, has a sensitivity of -49 dBm at a bit error rate of 10/sup 9/ under NRZ FSK reception at 200 Mb/s.<>     

Ultracompact monolithic integration of balanced, polarizationdiversity photodetectors for coherent lightwave receivers

The authors have monolithically integrated an optical front-end on InP for balanced, polarization-diversity coherent lightwave reception which is only 1.3-mm long. Low on-chip insertion loss (<4.5 dB) and balanced photoresponse (1.05:1 or better) are achieved at 1.5-μm wavelength using straightforward, regrowth-free fabrication. Low-capacitance photodetectors (⩽0.15 pF) are employed for high bandwidth operation     

Low-loss single-mode GaAs/AlGaAs miniature optical waveguides withstraight and bending structures

Low-loss single-mode GaAs/AlGaAs miniature optical waveguides fabricated for use in monolithically integrated optical circuits are discussed. The propagation characteristics of these waveguides with straight and S-bending structures have been investigated at wavelengths of 1.30 and 1.55 μm. The lowest propagation losses are estimated to be 0.58 dB/cm and 0.69 dB/cm at wavelengths of 1.30 and 1.55 μm, respectively. The total loss of an S-bending waveguide with a curvature radius of 2 mm and with a lateral displacement of 200 μm was 0.61 dB and 0.46 dB at wavelengths of 1.30 and 1.55 μm. The fabricated single-mode strip-loaded waveguides proved to be suitable for application of the semiconductor waveguide into monolithically integrated optical circuits     

2-4 GHz monolithic lateral p-i-n photodetector and MESFET amplifieron GaAs-on-Si

The design, fabrication, and evaluation of broadband lateral p-i-n photodetectors monolithically integrated with multistage MESFET amplifiers on GaAs-on-Si are described. Unique features of this approach are that (a) the lateral p-i-n structure is compatible with monolithic microwave integrated circuit (MMIC) technology and (b) the p-i-n detector is fabricated directly on the GaAs buffer layer without p⁺ and n⁺ implants, thus resulting in a simplified fabrication process. The operation of the circuit is compared to that of a similar circuit fabricated on a GaAs substrate. A quantum efficiency exceeding 60% has been measured for the p-i-n detectors. The 2- to 4-GHz frequency responses of one- and two-stage p-i-n/FET preamplifiers are presented. The response varies ±3 dB over the frequency band     

Flip-chip bonded arrays of monolithically integrated, microlensedvertical-cavity lasers and resonant photodetectors

We present flip-chip bonded arrays of monolithically integrated vertical-cavity lasers (VCLs) and resonant photodetectors. The VCLs and photodetectors are integrated using a novel structure that allows through-the-substrate emission and detection without compromising device performance. Substrate-side microlenses have been integrated to take advantage of the through-the-substrate architecture. Flip-chip bonded VCLs exhibit threshold currents as low as 135 μA with differential efficiencies of ~53%. The detectors have the same operating wavelength as the VCLs and responsivities of 0.48 A/W, corresponding to 60% absorption, with optical bandwidths of 7 nm     

Integrated directional couplers with photodetectors by hydridevapour phase epitaxy

The hydride vapour-phase-epitaxial crystal growth technique has been used to realise integrated waveguide-photodetectors and, for the first time, integrated directional coupler-photodetectors for detection in the 1.3 μm to 1.55 μm wavelength range. The GaInAsP waveguides which formed the directional couplers had propagation losses of 2±0.5 dB/cm and more than 90% of the guided light was coupled into the photodetectors. The directional couplers were symmetric with respect to the launch port and had 3 dB coupling lengths of about 1.45 mm     

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     

A Novel 4$, times ,$4 Optical Switch Using an Anisotropically Etched Micromirror Array and a Bistable Mini-Actuator Array

This letter presents a novel approach to realize a 4 times 4 optical switch. The optical switch consists of a micromachined silicon micromirror array and a bistable mini-actuator array. The micromirror array, which comprises vertical mirrors, cantilevers, and trenches, can be monolithically fabricated by a simple anisotropic silicon etching process in high precision and high yield. The mini-actuator array consists of 16 commercially available bistable actuators integrated with L-shape arms. The advantages of this approach include high precision, easy alignment, high fabrication yield, and low cost. Because of bistable actuation, the power consumption is very low and thus the temperature elevation of a working device is less than 0.3 K. The measured insertion losses of the four channels are between - 1.6 and - 2.3 dB. The measured crosstalk is less than -60 dB, and the measured switching time is about 13 ms.     

Integrated laser and add-drop optical multiplexer for narrowband wavelength division multiplexing

The fabrication and characterisation of a monolithically integrated narrowband add-drop multiplexer and DBR laser are reported. Multiplexer bandwidth of 2-3.5 nm have been measured with a Bragg extinction ratio >23 dB.<>     

Polarization independent dilated WDM cross-connect on InP

A four wavelength 2×2 optical wavelength-division-multiplexed cross-connect with dilated switches is reported. The device is monolithically integrated on InP and consist of two eight-channel PHASAR's combined with 16 electrooptic Mach-Zehnder interferometer switches. On-chip loss is less than -17 dB and crosstalk is better than -20 dB     

Silicon-on-Insulator CWDM Power Monitor/Receiver With Integrated Thin-Film InGaAs Photodetectors

In this letter, we demonstrate a compact and cost-effective four-channel demultiplexer with integrated photodetectors for application in coarse wavelength-division-multiplexing systems. The device consists of a silicon-on-insulator planar concave grating (PCG) demultiplexer and heterogeneously integrated InAlAs-InGaAs metal-semiconductor-metal photodetectors, and has a footprint of only 0.1 mm² . The PCG and integrated photodetectors have a responsivity of 0.6 A/W for TE-polarized light. The integrated device has an optical crosstalk of -25 dB.     

Monolithically integrated optical channel monitor for DWDM transmission systems

The design, fabrication, and performance of an InP-based monolithically integrated optical power monitor are presented. It contains 44 wavelength channels separated by 100 GHz and demonstrates record small footprint size. The device's major components, which include the echelle diffractive grating demultiplexer, passive waveguide circuitry and single-mode vertically integrated waveguide PIN photodetectors, are characterized and discussed as generic building blocks of InP-based planar lightwave technology for DWDM.     

Ku-band antenna array feed distribution network with ferroelectric phase shifters on silicon

This paper presents the design, fabrication, and experimental results of a 1 : 4 monolithic power distribution network for Ku-band array antenna applications. The network integrated on a high-resistivity silicon (HRS) substrate surface stabilized by polysilicon consists of three Wilkinson power dividers, four dc blocking filters, and four coplanar waveguide (CPW)-to-microstrip (MS) transitions. Each output ports are fed with a barium-strontium-titanate phase shifter. It is found that the introduction of the polysilicon layer between the oxide and HRS reduces RF losses significantly, which will enable the monolithic integration of high-power controller modules onto silicon because of the existence of the oxide layer, preventing any degradation of RF performances. The individual components show insertion losses ranging from 0.4 to 2.6 dB at 15 GHz, and the interconnecting CPW lines result in a loss of 0.064 dB/mm. This network was successfully integrated with MS patch antennas monolithically, showing good performance of 32-dB return loss at 14.85 GHz, and 10/spl deg/ beam-steering capability.     

Optical properties of epitaxialLaF3/SrF2/GaAs(111) heterostructure waveguidesfabricated by molecular beam epitaxy

Thin film slab waveguides of lanthanum fluoride clad with strontium fluoride grown epitaxially on GaAs (111) are characterized by optical and structural techniques. Crystallinity, surface roughness, refractive indexes and propagation loss measurements suggest that these structures show promise for monolithically integrated infrared (IR) pumped IR down-conversion and visible upconversion laser devices. Propagation losses as low as 3.7 dB/cm at 633 nm were measured in samples which show waveguide propagation over distances of several centimeters. Simulation of the scattering losses due to surface roughness provides an approximate delineation of surface and nonsurface contributions to the optical loss. Typical root-mean-square surface roughness of the lanthanum fluoride layer was on the order of 3 nm. The morphology appears to be dominated by grain boundaries     

Fabrication of (Pb,La)(Zr,Ti)O/sub 3/ thin-film arrayed waveguide grating

The design and fabrication of an 8-ch, 500 GHz-spacing arrayed waveguide grating on (Pb,La)(Zr,Ti)O₃ has been successfully achieved for the first time. An insertion loss of 22.1 dB, including a 10 dB coupling loss, and an adjacent crosstalk of -23.1 dB have been obtained. The device is expected to be monolithically integrated into high-speed optical switches to form integrated chips such as a reconfigurable add-drop multiplexer     

2 Gb/s operation of an optical-clock-driven monolithicallyintegrated GaAs D-flip-flop with metal-semiconductor-metalphotodetectors for high-speed synchronous circuits

Two Gb/s operation of an optical-clock-driven GaAs D-flip-flop is demonstrated which is monolithically integrated with metal-semiconductor-metal photodetectors. Optical-clock pulses of 100-ps pulsewidth generated from a semiconductor laser were used for the optical clock input. The relationship between optical clock input power and output signal waveform is determined     

Investigation of adjacent channel crosstalk in multichannelmonolithically integrated 1.55 μm photoreceiver arrays

We have investigated adjacent channel crosstalk in 3-, 8-, and 16-channel InP-based monolithically integrated p-i-n/HBT photoreceiver arrays, with a channel bandwidth of 11 GHz. By using a novel monolithically integrated radiation shield, we have been able to reduce the crosstalk to -35 dB at 10 GHz. These parameters represent the best performance in multichannel integrated photoreceiver arrays. The two main components of crosstalk are found to be radiation crosstalk and electrical crosstalk and these are separately dependent on interchannel spacing and single- or dual-source biasing schemes. An electromagnetic full-wave solution shows that the measured crosstalk in arrays without the radiation shield could be dominated by radiation crosstalk, which can be modeled as a capacitive coupling between adjacent channels. Similarly, electrical crosstalk can be modeled by equivalent parasitic resistive and inductive elements. Values of these circuit elements have been determined by analyzing experimental data     

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     

Photodétecteurs en intégration monolithique sur guides optiques : modélisation et vérifications expérimentales

The authors developed a model on optical guided structures with complex refractive indices, on 9 desktop-computer. This model allows to predict the coupling efficiency of photodetectors monolithically integrated with optical waveguides. An oscillatory behaviour of the absorption coefficient versus the absorbing layer thinkness has been pointed out. Comparisons with experimental resuylts obtained with device made in different laboratories show a good agrement     

Integration of a laser diode with a polymer-based waveguide forphotonic integrated circuits

The fabrication and characterization of BRS lasers monolithically integrated with butt-coupled polymer-based buried strip waveguides is presented. Threshold currents of lasers with one cleaved and one etched mirror facets are 15-18 mA and waveguide output powers are in excess of 5 mW at 100 mA laser driving currents and for 600 μm long waveguides. The device exhibits a total waveguide insertion loss less than 5 dB. The integrated device is potentially suitable as a building-block for photonic integrated circuits