M.K. Emsley

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 Single-Photon Avalanche Diodes on Reflecting Silicon Substrates

In this letter, we report the first resonant-cavity-enhanced single-photon avalanche diode (RCE SPAD) fabricated on a reflecting silicon-on-insulator (SOI) substrate. The substrate incorporates a two-period distributed Bragg reflector fabricated using a commercially available double-SOI process. The RCE SPAD detectors have peak photon detection efficiencies ranging from 42% at 780 nm to 34% at 850 nm and time resolution of 35-ps full-width at half-maximum. Typical dark count rates of 450, 3500, and 100 000 c/s were measured at room temperature with RCE SPADs having, respectively 8-, 20-, and 50-mum diameter.

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.

Silicon resonant-cavity-enhanced photodetector arrays for optical interconnects

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 inter-chip 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, manufacturing high speed, high efficiency silicon photodetectors presents a technical challenge. Resonant cavity enhanced (RCE) Si photodetectors have been shown to provide the required bandwidth-efficiency product and we have recently developed a method to reproduce them through commercially available fabrication techniques. In this work, commercially reproducible silicon wafers with a 90% reflectance buried distributed Bragg reflector (DBR) are used to create Si-RCE photodetector arrays for optical interconnects. The Si-RCE photodetectors have 40% quantum efficiency at 860 nm, a FWHM of 25 ps, and a 3dB bandwidth in excess of 10 GHz. We also demonstrate Si-RCE 12×1 photodetector arrays that have been fabricated and packaged with silicon based amplifiers to demonstrate the feasibility of a low cost monolithic silicon photoreceiver array.

High-efficiency, 10 GHz bandwidth resonant-cavity-enhanced silicon photodetectors operating at 850 nm wavelength

We present RCE Si pin photodetectors capable of quantum efficiency of /spl sim/40% and bandwidth of /spl sim/10 GHz at 850 nm with a buried distributed Bragg reflector fabricated by means of a double-SOI technique. The reflecting wafers are commercially reproducible and have single crystalline silicon device layers for fabricating silicon RCE photodiodes with high bandwidth efficiencies as well as low dark current. These wafers are well suited for VLSI integration and are compatible with standard CMOS processing making them ideal for monolithic integration of receiver circuits with photodetectors.