Integratable High Linearity Compact Waveguide Coupled Tapered InGaAsP Photodetectors

• Published in: IEEE journal of quantum electronics Vol. 43; no. 7; pp. 597 - 606
• Main Authors: Agashe, S.S., Kuen-Ting Shiu, Forrest, S.R.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01-07-2007; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Absorption; Applied sciences; Architecture; Bulk; Circuit properties; Current density; Electric, optical and optoelectronic circuits; Electronics; Exact sciences and technology; high power; Integrated optics. Optical fibers and wave guides; Linearity; Noise levels; Optical and optoelectronic circuits; optical integration; Optical saturation; Optical sensors; Optical waveguides; Optoelectronic devices; Photodetectors; Photodiodes; quantum well (QW); Quantum wells; Saturation; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Shape; Waveguides; Quantum well; Density of states; Gallium arsenides; high power; optical integration; Space charge; Multiple quantum well; Gallium phosphide; Photodiode; Photodetector; Bulk; Indium arsenides; Indium phosphide; Response function; Quaternary compound; quantum well (QW); photodiodes; Optical waveguide; Current density
• ISSN: 0018-9197; 1558-1713
• DOI: 10.1109/JQE.2007.897927

We investigate high linear response tapered photodiodes composed of bulk and multiquantum-well absorption layers based on the integratable asymmetric twin waveguide architecture. The tapered shape reduces space-charge induced nonlinearities, enhancing the saturation current densities at high input optical powers. The 1-dB compression current density for an InGaAsP bulk active layer photodiode (BPD) is in excess of (2.8 plusmn 0.3) kA/cm 2 , compared to quantum-well photo- diodes (QWPD) in the same materials system that saturate at (1.2 plusmn 0.1) kA/cm 2 . We find that the limited density of states of QWPDs leads to the early onset of current saturation. The BPD has a polarization sensitivity of S Pol = (1.0 plusmn 0.5) dB and responsivity R = (0.3plusmn0.03) A/W at a wavelength of 1.55 mum, whereas the QWPD has S Pol = (7plusmn1) dB and R = (0.55plusmn0.05) A/W, while both have a bandwidth of (11 plusmn 1) GHz.