Glenn Rankin

Blue Pr(3+)-doped ZBLAN fiber upconversion laser.

We demonstrate blue laser emission from a direct semiconductor laser-diode-pumped Pr(3+)-doped upconversion fiber laser. This laser produced more than 1 mW of power at a wavelength of 492 nm from pump lasers operating at 830 and 1020 nm.

Reduced sidelobe integrated acousto-optic filter with birefringence apodization

A two-section integrated acousto-optic tunable filter with significantly reduced sidelobes has been fabricated. The sidelobe reduction was achieved with birefringence apodization in the form of variable-width Ti-stripe waveguides. The design and fabrication of the device, which includes integrated proton-exchanged TE and TM-pass polarizers, are described. Experimental tuning curves for each filter section and the overall device are presented and compared with calculated results. The largest sidelobes were found to be 24 dB below the peak transmission, which represents a 5.3-dB improvement over an ideal filter without birefringence apodization. The FWHM of the filter is 1.36 nm, which is only 16% larger than predicted for its interaction length of 17 mm/section.

Direct integration of dense parallel optical interconnects on a first level package for high-end servers

The direct integration of dense 48-channel parallel multiwavelength optical transmitter and receiver subassemblies directly onto a first level package using a flex lead attach has been demonstrated. Such an approach, at 10 Gb/s/channel would provide a linear edge bandwidth density of 300 Gb/s/cm. By attaching dense multichannel optical subassemblies directly onto an MCM, the performance limitations of the connectors and node card wiring can be avoided and the total bandwidth off the MCM can be increased while also enabling longer distance and higher speed signaling. This approach involves only a modest modification to the bent-flex approach commonly used for parallel optical modules intended for board mounting but enables a significant density and performance improvement for this application.

Universal Photonic Interconnect for Data Centers

Tb/s class, co-packaged CWDM optical engine based on 4 wavelength VCSELs around 1μm is presented. The capability to scale bandwidth and link distance > 2km using single mode VCSELs and standard SMF28 fiber is demonstrated.

CWDM transceiver for mid-board optics

The need for additional IO bandwidth for data center device interconnection is well established. Optical interconnects can deliver required bandwidth along with energy and space efficiency at a cost that encourages adoption. To this end, we are developing an optical transceiver incorporating multimode VCSEL emitters in a coarse wavelength division multiplex (CWDM) system capable of transmission at 25Gbps per channel, 100Gbps/fiber, and a maximum aggregate bidirectional data rate of 1.2Tbps. Electrical connection to the transceiver can be made by solder reflow or LGA connector, and optical connection is made by means of a custom optical connector supporting CWDM transmission.

Progress towards low cost Tbps optical engines

A low cost Tb/s class CWDM optical engine prototype based on four different wavelength VCSELs around 1um is presented. 100Gbps operation per fiber is demonstrated.

Measurement and control of sidelobes in acousto-optic tunable filters

To summarize, we have examined the problems of high sidelobes in acousto optical tunable filters (AOTFs) and various possible solutions. While numerous apodization techniques to reduce sidelobes have been investigated, the experimental results are much worse than predicted due to waveguide nonuniformity. We point out that very little effort has gone into measuring these nonuniformities, eliminating them through better fabrication, or building devices which correct or better tolerate non-uniform waveguides. Finally, a number of techniques were discussed to address these issues.