Development of a Low-Impedance Traveling Wave Amplifier based on InAlAs/InGaAs/InP-HFET for 20 Gb/s Optoelectronic Receivers

The applicability of the transimpedance amplifier for optoelectronic receivers becomes doubtful for bit rates higher than 20 Gb/s. So recently the traveling wave amplifier (TWA) concept for high bit rate receiver systems is of increasing interest because it is the preferred amplifier concept for broadband applications like hierarchically organized communication interlinks. TWAs usually are designed with an input and output impedance of 50 Ω. Thus a main problem of the TWA-concept for an optoelectronic receiver is matching the photo-detector (PD) and the TWA input and reach the requested input RC-bandwidth. The conventional approach is a TWA with an additional 50 Ω match resistor at the input line, which has to be integrated directly into the PD itself in order to avoid parasitics. The aim of this paper is to present an alternative concept to the match resistor realized by a TWA with a low-impedance input (25 Ω), which yields significantly reduced design and fabrication efforts. All simulations for the investigated and optimized designs of the TWA in coplanar technique have been carried out using a commercially available software. For exact noise and sensitivity simulations, an extended temperature noise model (TNM) for heterostructure field-effect transistors was developed and implemented. Finally a comparison with measurement results of the realized TWA is presente

On the Applicability of the Transimpedance Amplifier Concept for 40 Gb/s Optoelectronic Receivers based on InAlAs/InGaAs Heterostructure Field-effect Transistors

We examine the design considerations and include a general discussion of the applicability of the transimpedance amplifier concept for optoelectronic receivers at extremely high bit rates up to 40 Gb/s. The receiver design is based on a low gate-leakage InAlAs-InGaAs-InP heterostructure field effect transistor (HFET). The noise modeling of these devices is done using an extended temperature noise model in order to produce a reliable extrapolation far beyond the frequency limits of common measurement setups. The fitted transistor model shows excellent agreement with measured data concerning RF as well as the noise performance. The evidence of inductive peaking near the corner frequency of the transimpedance Z_T is correlated to a phase difference between the voltage gain V_u and Z_ T itself. Furthermore, the distinct influence of the length of the feedback line on the receiver performance is discussed. Based on 0.7 μm gate HFETs produced by optical lithography and offering a current gain cut off frequency of fT=40 GHz the following receiver features can be predicted: low frequency transimpedance Z_T0=39.4 dBΩ, corner frequency f3dB=22 GHz, mean equivalent input noise current density i¯na≈43 pA/√Hz. Thus the receiver shows an excellent calculated sensitivity of ηPmin=-13.2 dBm at 40 Gb/

Ultrafast Monolithically Integrated InP-Based Photoreceiver: OEIC-Design, Fabrication, and System Application

An InP-based photoreceiver OEIC for λ=1.55 μm with a bandwidth of 27 GHz is reported. The receiver design, fabrication and characterization is presented. The device consists of an optical waveguide-fed pin-photodiode and a coplanar traveling-wave amplifier being composed of four GaInAs-AlInAs-InP-HEMT's. The photodiode exhibits an external quantum efficiency of 30% and a 3-dB power bandwidth of 35 GHz. HEMT's with 0.7-μm gate length, integrated on semi-insulating optical waveguide layers show cutoff frequencies fT/fmax of 37/100 GHz at zero gate bias. Traveling-wave amplifiers with 0.5-μm gate HEMT's have 28-GHz bandwidth. The receiver OEIC is packaged into a module with fiber pigtail and operates successfully within an SDH based 20-Gb/s transmission system. An overall system sensitivity of -30.5 dBm was achieved at a BER=10-9 after signal transmission over 198-km dispersion shifted fibe

10 Gb/s low-noise transimpedance amplifier for optoelectronic receivers based on InAlAs/InGaAs/InP HEMTs

A transimpedance amplifier based on 0.7 μm InAlAs/InGaAs/InP HEMTs and applicable for bit rates in the range of 2.5-10 Gb/s has been developed and realized. Compact chip layout guarantees extremely flat gain, linear phase and very small group delay time variations, respectively. Measured transimpedance is ZTO=51.6 dBΩ (f3 dB=8.5 GHz) for the 10 Gb/s version. Mean equivalent input noise current density is ina=7.98 pA/√(Hz) over the bandwidth 0⩽f⩽10 GHz. Calculated receiver sensitivity is ηPmin=-24.1 dBm@10 Gb/s and BER=10-

20 Gbit/s InP-based Photoreceiver Module: Application in nonrepeatered TDM with 198 km DSF

A 20 Gbit/s monolithic InP-based photoreceiver module for /spl lambda/=1.55 /spl mu/m is reported. It operates successfully with an overall receiver sensitivity of -30.7 dBm (BER=10/sup -9/) within an electrical TDM transmission system comprising 198 km of dispersion-shifted fibre

27 GHz Bandwidth Integrated Photoreceiver Comprising a Waveguide Fed Photodiode and a GaInAs/AlInAs-HEMT based Travelling Wave Amplifier

Optical front-ends are considered to play a major role in future communication systems operating at bit rates of 20 or even 40 Gbit/s, as well as in mobile communication systems with fibre-optic distribution networks. Consequently, different approaches for the monolithic integration of high-speed receivers for a wavelength of 1.55 /spl mu/m can be found in the literature. In this paper, we report on the first monolithical integration of an optical receiver OEIC, which combines the advantageous high-speed characteristics of the waveguide integrated pin photodiode and of the travelling wave amplifier (TWA) circuit, both based on the InP material system

Ultrafast GaInAs/AlInAs/InP Photoreceiver based on Waveguide Architecture

An InP-based photoreceiver OEIC with a bandwidth of 27 GHz is reported. The device consists of a pin-photodiode with integrated optical waveguide and a coplanar travelling wave amplifier being composed of four HEMTs