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Fremont, CA, United States

Murugan G.S.,University of Southampton | Zervas M.N.,University of Southampton | Panitchob Y.,University of Southampton | Panitchob Y.,Opnext | Wilkinson J.S.,University of Southampton
Optics Letters

A neodymium-doped BK7 glass microsphere laser integrated with a planar ion-exchanged waveguide pumped at 0:8 μm has been demonstrated. The pump radiation was launched by evanescent coupling from the waveguide, and the signal radiation was coupled out through the same waveguide, offering the potential for robustly assembled fully integrated active optical circuits. The dependence of the lasing spectra on pump power and wavelength were studied in detail to clarify the whispering-gallery-mode behavior at the pump and lasing wavelengths. © 2010 Optical Society of America. Source

Traverso M.,Opnext

The Optical Internetworking Forum (OIF) has started the development of Implementation Agreements (IA) for optical transmitters and receivers to deal with the need for 100-Gbps DWDM optical interfaces. The OIF has focused on a modulation scheme known as dual-polarization quadrature phase-shift keying (DP-QPSK) paired with coherent detection. The DP-QPSK modulation scheme reduces the symbol rate relative to a 100-Gbps bit rate in two fundamental ways such as the signal is split into two polarization states, allowing the required symbol rate to be divided in half and the signal is phase modulated with two bits per symbol, dividing the required symbol rate in half. The DP-QPSK optical transmitter and receiver require multiple elements to support their operation such as optical transmitter has polarization elements and modulation elements, while the receiver must support polarization elements and optical mixing elements and high-speed photodetectors and electronics. Source

Quad Small Form factor pluggable plus (QSFP+) transceiver modules using multimode optics have gained increasing traction in very short-reach InfiniBand applications. The largest growth area for QSFP+ continues to be in data centers where bandwidth demand continues to increase. Here, most uplinks from the switches to the cluster switch are still multimode 10GbE connections, yet, there has been some migration to 40GbE, mainly using QSFP+ modules. QSFP+ offer significant advantages over the CFP design and can combine four transmitter optical subassemblies (TOSAs) into a single integrated component. The transition from CFP to QSFP+ not only requires significant optical integration, but also power consumption reduction of the optical and electrical components. Studies have found that 40GbE transceivers in a QSFP+ form factor are poised to address both multimode and singlemode applications in a variety of market spaces. Source

Some of the next-generation 40/100 Gigabit Ethernet transceiver technologies and designs are reviewed. The first-generation 40GBase-LR4 optical transceiver is based on a 4×10G architecture that comprises 10G CWDM 1310-nm uncooled directly modulated distributed feedback (DM-DFB) transmit optical subassemblies (TOSA). The CFP 40GBase module power dissipation is typically in the range of 6W, which fits well within the CFP module's 32-W power maximum. CFP 100GBase-LR4/ER4 is similar to the CFP 40GBase transceiver. A 10:4/4:10 gearbox serializer/deserializer IC is used to implement the electrical interface between the 10-lane host data path and the four lane optical data path. The receiver optical specifications for LR4 and ER4 are based upon PIN-PD detector technology with integrated TIA. First generation 40GbE/100GbE CFP optical transceivers are now completing customer qualification. Source

Batshon H.G.,University of Arizona | Djordjevic I.,University of Arizona | Schmidt T.,Opnext
Optics Express

We propose a subcarrier-multiplexed four-dimensional LDPC bit-interleaved coded modulation scheme that is capable of achieving beyond 480 Gb/s single-channel transmission rate over optical channels. Subcarrier-multiplexed four-dimensional LDPC coded modulation scheme outperforms the corresponding dual polarization schemes by up to 4.6 dB in OSNR at BER 10-8. © 2010 Optical Society of America. Source

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