Mike Morse

High speed silicon Mach-Zehnder modulator

We demonstrate a silicon modulator with an intrinsic bandwidth of 10 GHz and data transmission from 6 Gbps to 10 Gbps. Such unprecedented bandwidth performance in silicon is achieved through improvements in material quality, device design, and driver circuitry.

31 GHz Ge n-i-p waveguide photodetectors on Silicon-on-Insulator substrate.

We report on evanescently coupled Ge waveguide photodetectors that are grown on top of Si rib waveguides. A Ge waveguide detector with a width of 7.4mum and length of 50 mum demonstrated an optical bandwidth of 31.3 GHz at -2V for 1550nm. In addition, a responsivity of 0.89 A/W at 1550 nm and dark current of 169 nA were measured from this detector at -2V. A higher responsivity of 1.16 A/W was also measured from a longer Ge waveguide detector (4.4 x 100 mum2), with a corresponding bandwidth of 29.4 GHz at -2V. An open eye diagram at 40 Gb/s is also shown.

Demonstration of a High Speed 4-Channel Integrated Silicon Photonics WDM Link with Hybrid Silicon Lasers

The demonstration of a 4λ×10Gbps Silicon Photonics CWDM link integrating all optical components, electronics and packaging technologies required for system integration is reported. Further demonstration of the link operating at 50Gbps, 4λ×12.5Gbps, is also shown.

Frequency response and bandwidth enhancement in Ge/Si avalanche photodiodes with over 840GHz gain-bandwidth-product

In this work we report a separate-absorption-charge-multiplication Ge/Si avalanche photodiode with an enhanced gain-bandwidth-product of 845 GHz at a wavelength of 1310 nm. The corresponding gain value is 65 and the electrical bandwidth is 13 GHz at an optical input power of -30 dBm. The unconventional high gain-bandwidth-product is investigated using device physical simulation and optical pulse response measurement. The analysis of the electric field distribution, electron and hole concentration and drift velocities in the device shows that the enhanced gain-bandwidth-product at high bias voltages is due to a decrease of the transit time and avalanche build-up time limitation at high fields.

40Gb/s Ge-on-SOI waveguide photodetectors by selective Ge growth

Ge waveguide photodetectors with dimension of 7.4 μm × 50 μm and 4.4 μm × 100 μm demonstrated optical bandwidth of 31.3 GHz and 29.4 GHz, responsivity of 0.89 A/W and 1.16 A/W at 1550 nm, and 40 Gb/s open eye diagrams at -2V.

Epitaxially-grown Ge/Si avalanche photodiodes for 1.3µm light detection

We designed and fabricated Ge/Si avalanche photodiodes grown on silicon substrates. The mesa-type photodiodes exhibit a responsivity at 1310nm of 0.54A/W, a breakdown voltage thermal coefficient of 0.05%/°C, a 3dBbandwidth of 10GHz. The gain-bandwidth product was measured as 153GHz. The effective k value extracted from the excess noise factor was 0.1.

Integrated silicon photonics for optical networks [Invited]

Feature Issue on Nanoscale Integrated Photonics for Optical Networks Fiber optic communication is well established today in long-haul, metro, and some data communication segments. Optical technologies continue to penetrate more into the network owing to the increase in bandwidth demands; however, they still suffer from too expensive solutions. Silicon photonics is a new technology developing integrated photonic devices and circuits based on the unique silicon material that has already revolutionized the face of our planet through the microelectronics industry. This paper reviews silicon photonics technology at Intel, showing how using the same mature, low-cost silicon CMOS technology we develop many of the building blocks required in current and future optical networks. After introducing the silicon photonics motivation for networks, we discuss the various devices--waveguides, modulators, Raman amplifiers and lasers, photodetectors, optical interconnects, and photonic crystals--from the points of view of applications, principle of operation, process development, and performance results.

Micron-sized channel-dropping filters using silicon waveguide devices

High density integrated optics on the scale of VLSI is of interest as it allows complicated optical interconnect circuitry to be mass produced. In this paper we present micron-sized high Q resonant cavity structures based on silicon on insulator devices. These resonant cavities may be used in channel dropping filters and modulators. Because of their small size, they have high packing densities on the order of one million devices per square centimeter. This technology has the added advantage in that it can utilize the embedded VLSI electronics manufacturing capacity. In previous work, we studied silicon on oxide photonic band gap (PBG) devices and demonstrated devices with a 400 nm stop band and with a defect which had a Q of 265 centered at a wavelength of 1560 nm. In addition, we fabricated 3 to 5 micrometer radii micro-rings with Qs of approximately 250 and free spectral widths of over 20 nm. In this work, we report results on micro-racetracks, which are oval shaped resonators, with resonances that are approximately 16 nm apart and Qs of about 1000. These racetracks incorporate a vertical coupling technology in which the bus waveguides and the ring are on separate planes. This vertical coupling scheme allows for independent control of the Q of the ring via the distance between the ring and the bus. We demonstrate higher order multi-resonator filters with similar Q and free spectral range to the single resonator filters. The individual resonators in each filter have slightly different resonant frequencies from each other resulting in multi-peaked resonances and lower drop efficiencies. Finally, we show that it is possible to thermally tune the resonances by 1 nm leading to a 10:1 contrast ratio.

Monolithic Ge/Si avalanche photodiodes

We demonstrate mesa-type and waveguide-type Ge/Si avalanche photodiodes both with high performances. The gain-bandwidth product was measured as high as 340GHz and the receiver sensitivity was −28dBm and −30.4dBm for mesa-and waveguide-type devices, respectively.

Resonant normal-incidence separate-absorption-charge-multiplication Ge/Si avalanche photodiodes.

In this work the impedance of separate-absorption-charge-multiplication Ge/Si avalanche photodiodes (APD) is characterized over a large range of bias voltage. An equivalent circuit with an inductive element is presented for modeling the Ge/Si APD. All the parameters for the elements included in the equivalent circuit are extracted by fitting the measured S(22) with the genetic algorithm optimization. Due to a resonance in the avalanche region, the frequency response of the APD has a peak enhancement when the bias voltage is relatively high, which is observed in the measurement and agrees with the theoretical calculation shown in this paper.