O. Dosunmu

High-speed resonant cavity enhanced Ge photodetectors on reflecting Si substrates for 1550-nm operation

We have designed and fabricated high-speed resonant cavity enhanced germanium (Ge) Schottky photodetectors on a silicon-on-insulator substrate. These back-illuminated detectors have demonstrated 3-dB bandwidths of more than 12 GHz at 3-V reverse bias and a peak quantum efficiency of 59% (R=0.73 A/W) at the resonant wavelength of /spl sim/1540 nm. Time domain measurements of our Ge photodetectors with diameters of up to 48 /spl mu/m show transit-time limited impulse responses corresponding to bandwidths of at least 6.7 GHz, making these detectors compatible with 10-Gb/s data communication systems.

High-speed resonant-cavity-enhanced silicon photodetectors on reflecting silicon-on-insulator substrates

We report a resonant-cavity-enhanced Si photodetector fabricated on a reflecting silicon-on-insulator (SOI) substrate. The substrate incorporates a two period distributed Bragg reflector (DBR) fabricated using a commercially available double-SOI process. The buried DBR provides a 90% reflecting surface. The resonant-cavity-enhanced Si photodetectors have 40% quantum efficiency at 860 nm and response time of 29 ps. These devices are suitable for 10-Gb/s data communications.

Silicon substrates with buried distributed Bragg reflectors for resonant cavity-enhanced optoelectronics

We report on a commercially reproducible silicon wafer with a high-reflectance buried distributed Bragg reflector (DBR). The substrate consists of a two-period DBR fabricated using a double silicon-on-insulator (SOI) process. The buried DBR provides a 90% reflecting surface. We have fabricated resonant cavity-enhanced Si photodetectors with 40% quantum efficiency at 860 nm and a full-width at half-maximum of 29 ps suitable for 10 Gbps data communications. We have also implemented double-SOI substrates with 90% reflectivity covering 1300 and 1550 nm for use in Si-based optoelectronics.

Resonant cavity enhanced Ge photodetectors for 1550 nm operation on reflecting Si substrates

We have fabricated and characterized the first resonant cavity-enhanced germanium photodetectors on double silicon-on-insulator substrates (Ge-DSOI) for operation around the 1550-nm communication wavelength and have demonstrated over four-fold improvement in quantum efficiency compared to its single-pass counterpart. The DSOI substrate is fabricated using an ion-cut process and optimized for high reflectivity (>90%) in the 1300-1600-nm wavelength range, whereas the Ge layer is grown using a novel two-step ultra-high vacuum/chemical vapor deposition direct epitaxial growth technique. We have simulated a Ge-DSOI photodetector optimized for operation at 1550 nm, exhibiting a quantum efficiency of 76% at 1550 nm given a Ge layer thickness of only 860 nm as a result of both strain-induced and resonant cavity enhancement. For this Ge thickness, we estimate a transit time-limited 3-dB bandwidth of approximately 25 GHz.

High-speed high-efficiency large-area resonant cavity enhanced p-i-n photodiodes for multimode fiber communications

In this letter, we report AlGaAs-GaAs p-i-n photodiodes with a 3-dB bandwidth in excess of 10 GHz for devices as large as 60-/spl mu/m diameter. Resonant cavity enhanced photodetection is employed to improve quantum efficiency, resulting in more than 90% peak quantum efficiency at 850 nm.

Realization of high-efficiency 10 GHz bandwidth silicon photodetector arrays for fully integrated optical data communication interfaces

We present a commercially reproducible fabrication technique for producing high quantum efficiency photodiodes with up to 10 GHz bandwidth on double silicon-on-insulator (SOI) wafers. The substrate consists of a two-period distributed Bragg reflector (DBR), which provides a 90% reflecting surface. Resonant-cavity-enhanced (RCE) Si photodetectors with 40% quantum efficiency at 860 nm and a FWHM of 29 ps suitable for 10 Gbps data communications are demonstrated We also demonstrate integrated photodiode arrays in silicon substrate for multi-channel high speed serial interfaces.

High-speed Si resonant cavity enhanced photodetectors and arrays

Over the past decade a new family of optoelectronic devices has emerged whose performance is enhanced by placing the active device structure inside a Fabry–Perot resonantmicrocavity [P. E. Green, IEEE Spectrum 13 (2002)]. The increased optical field allows photodetectors to be made thinner and therefore faster, while simultaneously increasing the quantum efficiency at the resonant wavelengths. We have demonstrated a variety of resonant cavity enhanced (RCE) photodetectors in compound semiconductors [B. Yang, J. D. Schaub, S. M. Csutak, D. J. Rogers, and J. C. Campbell, IEEE Photonics Technol. Lett. 15, 745 (2003)] and Si [M. K. Emsley, O. I. Dosunmu, and M. S. Unlu, IEEE J. Selected Topics Quantum Electron. 8, 948 (2002)], operating at optical communication wavelengths ranging from 850 nm to 1550 nm. The focus of this article is on Si photodetectors and arrays. High bandwidth short distance communications standards are being developed based on parallel optical interconnect fiber arrays to meet the needs of increasing data rates of interchip communication in modern computer architecture. To ensure that this standard becomes an attractive option for computer systems, low cost components must be implemented on both the transmitting and receiving end of the fibers. To meet this low cost requirement silicon based receiver circuits are the most viable option, however, high speed, high efficiency siliconphotodetectors present a technical challenge. Commercially reproducible silicon wafers with a high reflectance buried distributed Bragg reflector (DBR) have been designed and fabricated [M. K. Emsley, O. I. Dosunmu, and M. S. Unlu, IEEE J. Selected Topics Quantum Electron. 8, 948 (2002)]. The substrates consist of a two-period, 90% reflecting, DBR fabricated using a double silicon-on-insulator (SOI) process. Resonant-cavity-enhanced (RCE) Si photodetectors have been fabricated with 40% quantum efficiency at 850 nm and a FWHM of 29 ps suitable for 10 Gbps data communications. Recently, 1×12 photodetector arrays have been fabricated, packaged, and tested with silicon based amplifiers to demonstrate the feasibility of a low cost solution for optical interconnects.

High speed resonant-cavity enhanced Ge photodetectors on reflecting Si substrates for 1550 nm operation

We have fabricated high-speed resonant cavity enhanced Ge-on-SOI photodetectors, demonstrating 3 dB bandwidths of more than 12 GHz at 3 V reverse bias and a peak quantum efficiency of 59% at the resonant wavelength of 1540 nm.

Germanium on double-SOI photodetectors for 1550 nm operation

In this paper, we have fabricated a resonant cavity enhanced (RCE) Ge-on-double-silicon on insulator (SOI) photodetector for operation around the 1550 nm communication wavelength. The enhanced response of this detector is attributed to both the resonant cavity effect as well as the strain induced band gap narrowing of the Ge layer.

Resonant cavity enhanced photodiodes with a broadened spectral peak

We have designed, fabricated, and characterized a novel RCE PD that exhibits a wider and flatter peak quantum efficiency when compared with a standard RCE PD. Unlike conventional RCE devices, these devices that have increased tolerance to wavelength variations can be used in short haul optical communications complementing VCSELs.