No abstract

We present a theoretical analysis on the II. INVESTIGATED STRUCTURES quantum efficiency of a resonant cavity InGaAs/GaAs P-i-nThe schematic of a In02Ga08As/GaAs RCE PD is in Fig. Ia. photodetector (PD) for the ultrashort optical connections. The In0.2Ga0.8As absorbing layer sandwiched between two GaAs numerical method of calculation of quantum efficiency combining a transfer matrix method and a energy conservation law is spacer layers. Since the increase of length of the resonator offered. Using anomalous dispersion (AD) mirror as the top leads to narrowing the spectrum, optical length of mirror flattopped QE spectrum has been obtained. Conditions for In0.2Ga0.8As/GaAs cavity is equal to the wavelength. The top ideal flattopped the spectral response have been received. We and the bottom mirrors are quarter-wave stacks of present a design with a maximum QE of 93.5% and 3 nm Al065Ga035As/GaAs designed for high reflectance at 980nm bandwidth at 0.02 dB below the peak.center wavelength. Fig. lb shows design with a 2/2-defect in top mirror leading I. INRODUCTION to anomalous dispersion effect. The values of parameters for Today resonant cavity enhanced photodetectors are both structures presented in Table I. promising devises for optical interconnects [1], optical sensing applications, and metrology. Inserting a photosensitive active Air Light medium into Fabry-Perrot resonator results in enhanced 4 G W quantum efficiency due to multiple reflections between mirrors . G { Light a 14A0_65Gao.35As [2]. As mirrors can be used distributed Bragg reflectors Air + ____________X . (DBRs), since the reflectivity of DBRs is very high. Resonant-0 e 4 GaAs cavity enhanced photodetector (RCE PD) possesses high speed X./4 A06Ga3A AS defec operation and wavelength selectivity and is proper devise for 00 4 A G A * 1 r ron 1 r 1 * 1 a E-°~~~~~~~~~~/ hlA10.65Gall.35AM X O 4 A0.65Gao3As data transfer systems [3]. The presence of the cavity leadls to a !! narrow bandwidth (BW) determined first of all by cavity length Spacer layer GaAs Spacer layer GaAs and reflectance of mirrors. However, for the certain Active layer ln0,Ga,,As Active layer In2Ga0,,As applications (e.g. high-speed telecommunications, optical Spacer layer GaAs Spacer layer GaAs interconnects and free-space communications) receivers with , /4 Al,65Ga.35As X XI4 Al065Gao35As the broad-band flat-topped spectral response are required. -_ _ _ _ Moreover, for application of the photodetector in bi-directional V G J GaAs optical interconnects the successful decision of the cavity-p/ A106,5Ga035As X]4 A!0.65Gao,3,AAs Substrate Substrate mode misalignment problem is important. Even a slight mismatch of the cavity-mode wavelengths of paired VCSELs a) b) and RCE-PDs may considerably degrade the receiver Fig. 1. Schematic model of a) conventional RCE PD and sensitivity. Cavity-mode tuning method offered earlier [4] b) RCE PD with a k/2-defect complicates fabrication of PDs, which can raise the production cost. Therefore, creation of the flat-topped quantum efficiency TABLE I MAIN PA...

No abstract

A theoretical analysis of the optical absorption and quantum efficiency (QE) in a resonant cavity enhanced InGaAs/GaAs P-i-n photodetector (RCE PD) is presented. Using anomalous dispersion (AD) mirror flattopped QE spectrum is obtained. The influence of the thickness and position of AD layer on the optical absorption and QE is shown and design with a maximum QE of 92.5% and 6 nm spectral flattop is presented.

No abstract