This PDF file contains the front matter associated with SPIE Proceedings Volume 9390, including the Title Page, Copyright information, Table of Contents, Authors, Introduction (if any), and Conference Committee listing.

A high-performance InAlAs avalanche photodiode (APD) with a vertical-illumination structure for 50-Gbit/s applications is presented. The vertical-illumination structure we employed is advantageous for large optical tolerance and thus enables easier optical coupling than waveguide structures. Although the vertical illumination structure generally has disadvantages in terms of both responsivity and bandwidth, our fabricated APD exhibits a high responsivity of 0.69 A/W with a large 3-dB bandwidth of over 30 GHz at a multiplication factor (M) of 4.6 and a large gain-bandwidth product of 270 GHz, thanks to an unique hybrid absorption layer of p-doped/undoped InGaAs and a thin InAlAs avalanche layer. Furthermore, an optical receiver assembled with the APD and a trans-impedance amplifier (TIA) successfully demonstrates 50-Gbit/s error-free operation for the first time. The receiver sensitivity of -10.8 dBm at a BER of 10-12 is obtained against non-return-to-zero optical input signals at a wavelength of 1310 nm. In these operating conditions, the power consumption of the APD receiver module is less than 500 mW, where more than 98 % of the power is consumed by the TIA. The obtained minimum receiver sensitivity is enough for 20-km transmission at 50 Gbit/s when we assume a launch power of 0 dBm and transmission loss in the optical fiber of 0.5 dB/km. These results indicate our APD is promising for the systems with a serial baud rate of 50 Gbit/s such as 400-Gbit/s Ethernet systems.

Seeing the recent vast data increase in information industry, IT society will move into the new era of Zettabyte in a few years. Under these circumstances, high-speed and high-capacity optical communication systems have been deployed in the industry. Especially high speed optical transceivers are key devices to realize high-speed systems, and the practical development is accelerated. In order to develop these leading edge products timely, the global standard criteria are strongly required in the industry. Based on these backgrounds, the forum standardization bodies such as OIF PLLWG/ IEEE802.3 are energetically creating the de-fact standards. With regard to 100G/400G standardization activities, IEEE802.3 leads the client side, and OIF PLL-WG leads the line side, and both of them play important roles in the industry. In the previous Photonics West conferences, the activities of these standardization bodies till 2013 were reported. In 2014, the discussions of 400G client side transceiver projects have made some progress in IEEE802.3, whose baseline technologies are about to be fixed. Also 100G transceiver projects for metro applications in the line side, whose target profile is CFP2 form factor, have been discussed in OIF PLL-WG. In this paper, these high-end standardization topics are introduced and the future products direction is also discussed from the technical point of view. In order to realize these small form factor and cost effective transceivers, the device integration technologies, the low power device/electrical circuit technologies, and the development of high speed electrical interface such as 25G/50G are key factors.

A complete single mode dual-core fiber system for short-reach optical interconnects is fabricated and tested for high-speed data transmission. It includes dual-core fibers capable of bi-directional data transmission, dual-core simplex LC connectors, and fan-outs. The transmission system offers simplified bi-directional traffic engineering with integrated bidirectional transceivers and compact system design, utilizing simplex dual-core LC connectors that use half the space while increasing the bandwidth density by a factor of two. The fiber has two cores that are compatible with single mode fiber and conforms to the industry standard outer diameter of 125 μm. This reduces operational complexity by reducing the size and number of fibers, cables and connectors. Measured OTDR loss for both cores was 0.34 dB/km at 1310 nm and 0.19 dB/km at 1550 nm. Crosstalk for a piece of 5.8 km long dual-core fiber was measured to be below -75 dB at 1310 nm, and below -40 dB at 1550 nm. Both free-space optics fan-outs and tapered-fiber-coupler based MCF fan-outs were evaluated for the transmission system. Error-free and penalty-free 25 Gb/s bi-directional transmission performance was demonstrated for three different fiber lengths, 200 m, 2 km and 10 km, using the complete all-fiber-based system including connectors and fan-outs. This single mode, dual-core fiber transmission system adds complementary value to systems where additional increases in bandwidth density can come from wavelength division multiplexing and multiple bits per symbol.

A failure recovery system utilizing a multi-core fiber (MCF) link with field programmable gate array-based optical switch units was developed to achieve high capacity and highly reliable optical networks in access areas. We describe the novel MCF link based on a multi-ring structure and a protection scheme to prevent link failures. Fan-in/ -out devices and connectors are also presented to demonstrate the development status of the MCF connection technology for the link. We demonstrated path recovery by switching operation within a sufficiently short time, which is required by ITU-T. The selection of a protecting path as a failure working path was also optimized as the minimum passage of units for low loss transmission. The results we obtained indicate that our proposed link has potential for the network design of highly reliable network topologies in access areas such as data centers, systems in business areas, and fiber to the home systems in residential areas.

We manufacture and compare parallel optical transceiver and receiver assemblies on test boards for parallel data transmission over multimode fiber using single mode (SM) and multimode (MM) vertical-cavity surface-emitting laser (VCSEL) arrays. VCSELs, GaAs PIN photodetector arrays, commercially-available 12 channel VCSEL driver arrays and 12 channel limiting amplifier arrays were assembled into multi-channel transceiver and receiver assemblies on testboards designed to operate up to 16 channels and coupled to multimode fiber ribbon through industrial connectors. MM VCSEL arrays easily allow 25 Gb/s error-free data transmission over 100m of OM4 fiber with only a minor penalty in the sensitivity (0.5 dB). As opposite increasing the distance to 150-200 m causes a strong increase in the noise level making the error free transmission at 200 m impossible. Using of single mode SM VCSEL arrays allows error-free 25 Gbit/s NRZ PRBS 2¹⁵-1 transmission over 1 km distances over OM4 fiber and above 600 m over OM3 fiber. In a different set of experiments PAM4 transmission up to 50 Gbit/s using SM VCSEL arrays is studied.

Silicon photonics has been widely researched as a potential technology for the next generation of optical devices due to its high integration capabilities. After presenting the first Brazilian high speed integrated 100G-DPQPSK transmitter, this paper brings the design and characterization of a compact integrated silicon coherent receiver, with a footprint of are 4.5 mm x 1 mm. The characterization was performed with 112 Gb/s DP-QPSK modulation resulting in an estimated BER of 5.46 x10^-7.

We propose, experimentally demonstrate, and evaluate the performance of a multimode (MM) transmission fiber data link which is based on orbital angular momentum (OAM) modes. The proposed scheme uses OAM modes to increase capacity or reach without recurring to mode division multiplexing (MDM) or special fibers: we first excite an OAM mode and couple it to a 50 m, 100 m, 200 m and 400m MM fibers. We compare three OAM modes and a conventional optical multimode under the same launch and received optical power conditions. The proposed OAM based solution is a promising candidate for the data centers interconnects and short range links that employ the existing multimode fiber infrastructure.

Monolithic integration of photonic functionality in the frontend-of-line (FEOL) of an advanced microelectronics technology is a key step towards future communication applications. This combines photonic components such as waveguides, couplers, modulators, and photo detectors with high-speed electronics plus shortest possible interconnects crucial for high-speed performance. Integration of photonics into CMOS FEOL is therefore in development for quite some time reaching 90nm node recently [1]. However, an alternative to CMOS is high-performance BiCMOS, offering significant advantages for integrated photonics-electronics applications with regard to cost and RF performance. We already presented results of FEOL integration of photonic components in a high-performance SiGe:C BiCMOS baseline to establish a novel, photonic BiCMOS process. Process cornerstone is a local-SOI approach which allows us to fabricate SOI-based, thus low-loss photonic components in a bulk BiCMOS environment [2]. A monolithically integrated 10Gbit/sec Silicon modulator with driver was shown here [3]. A monolithically integrated 25Gbps receiver was presented in [4], consisting of 200GHz bipolar transistors and CMOS devices, low-loss waveguides, couplers, and highspeed Ge photo diodes showing 3-dB bandwidth of 35GHz, internal responsivity of more than 0.6A/W at λ= 1.55μm, and ~ 50nA dark current at 1V. However, the BiCMOS-given thermal steps cause a significant smearing of the Germanium photo diodes doping profile, limiting the photo diode performance. Therefore, we introduced implantation of non-doping elements to overcome such limiting factors, resulting in photo diode bandwidths of more than 50GHz even under the effect of thermal steps necessary when the diodes are integrated in a high performance BiCMOS process.

We previously proposed a photonics-electronics convergence system to solve bandwidth bottlenecks among large scale integrations (LSIs) and demonstrated a high bandwidth density with silicon optical interposers at room temperature. For practical applications, interposers should be usable under high temperature conditions and rapid temperature changes so that they can cope with the heat generated by mounted LSIs. We designed and fabricated athermal silicon optical interposers integrated with temperature-insensitive components on a silicon substrate. An arrayed laser diode (LD) chip was flip-chip bonded to the substrate. Each LD had multiple quantum dot layers with a 1.3-µm lasing wavelength. The output power was higher than 10 mW per channel up to 100^º C. Silicon optical modulator and germanium photo detector (PD) arrays were monolithically integrated on the substrate. The modulators were structured as symmetric Mach- Zehnder interferometers, which were inherently temperature insensitive. The phase shifters composed of p-i-n diodes were stable against temperature with constant bias currents. The PD photo current was also temperature insensitive and the photo-to-dark current ratio was higher than 30 dB up to 100^º C. We achieved error-free data links at 20 Gbps and high bandwidth density of 19 Tbps/cm² operating from 25 to 125^º C with the interposers without adjusting of the LDs, modulators, or PDs. The interposers are tolerant of the heat generated by the mounted LSIs and usable over the extended industrial temperature range without complex monitoring or feedback controls. The bandwidth density is sufficient for the needs of the late 2010s.