Michael Tan

Low threshold 1.2 μm InGaAs quantum well lasers grown under low As/III ratio

We have achieved 160 A/cm2 threshold current density of a 1.21 μm InGaAs/GaAs quantum well (QW) laser grown under a very low As/III ratio. We investigated the As/III ratio dependence on the optical quality of InGaAs QWs grown with arsine and tertiarybutylarsine (TBA). We found that TBA allows us to grow high quality InGaAs QWs under a very low As/III ratio (∼3), while a higher As/III ratio (∼10) with arsine is necessary to obtain the similar quality QWs. This high quality InGaAs QW grown under the low As/III ratio leads to the realization of high quality InGaAsN QW which should be grown under a low As/III ratio and a high N/V ratio.

Demonstration of a compact low-power 250-Gb/s parallel-WDM optical interconnect

In this letter, we demonstrate error-free operation of a 12-fiber /spl times/4-wavelength /spl times/5.21-Gb/s parallel-wavelength-division-multiplexed (PWDM) optical link. The 250-Gb/s transmitter and receiver assemblies each have a 5/spl times/8-mm footprint and consume a combined power of 1.5 W. To our knowledge, this is the first publication of a fully functional PWDM optical interconnect as well as the highest demonstrated bandwidth per unit area and bandwidth per unit power consumption for any multiple-channel fiber-optic interconnect. This technology is intended for short-distance high-bandwidth-density applications such as multiprocessor computer backplanes.

500-Gbps Parallel-WDM Optical Interconnect

This paper describes a 500-Gbps parallel wavelength-division multiplexed (PWDM) optical interconnect where 48 channels of 10.42-Gbps data are transmitted over a parallel 12-fiber ribbon with 4 wavelengths per fiber. The transmitter and receiver are each chip-scale packages with a footprint of 5 mm times 8 mm and a combined power consumption of 3 W. This work is motivated by the continually increasing bandwidth needs of short-distance computer processor interconnects, which are demanding optical solutions that maximize bandwidth per unit area, power consumption, and cost

Al Contamination in InGaAsN Quantum Wells Grown by Metalorganic Chemical Vapor Deposition and 1.3 µm InGaAsN Vertical Cavity Surface Emitting Lasers

We obtained high-quality InGaAsN quantum wells (QWs) by metalorganic chemical vapor deposition (MOCVD). Our InGaAsN QWs showed low threshold current densities and high-temperature characteristics (550 A/cm2, 150 K at 1275 nm for 3QWs) in broad-area lasers. High output power (2.8 mW at 1280 nm) was also obtained from the room-temperature continuous operation of InGaAsN 3QW vertical cavity surface emitting lasers. We revealed the first solid evidence that unexpected Al incorporation (Al contamination) occurred in InGaAsN QWs continuously grown on GaAs/AlGaAs structures by MOCVD. Our results suggest that Al contamination leads to a rough surface and low photoluminescence intensity of the InGaAsN QWs. By minimizing Al contamination, high-quality InGaAsN QWs were obtained. Al contamination in InGaAsN QWs should be carefully considered in the MOCVD growth of InGaAsN-based devices.

Parallel-WDM for multi-Tb/s optical interconnects

This article presents a promising approach for multi-Tb/s optical interconnects. This approach is contained in the MAUI project, which develops a parallel multiwavelength optical subassembly (PMOSA) that uses PWDM to gain the component-density advantages of two-dimensional parallel optics and the connector and cabling density advantages of CWDM. In the MAUI approach, a standard multimode 12-fiber ribbon is used with 4 wavelengths transmitted through each fiber, for a total of 48 optical channels.

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.

Progress in long wavelength VCSELs

Advances in long wavelength VCSEL technology have demonstrated the feasibility of fabricating monolithic long wavelength VCSELs. Several new technologies such as InGaAsN quantum wells, low voltage tunnel junctions and novel DBR mirrors have dramatically improved the performance of long wavelength VCSELs. Common to both technologies is the need to have a manufacturable single mode, polarization locked VCSEL design. It will only be a matter of time before the long wavelength VCSEL will displace both FP and DFB lasers for medium reach applications. For the metro/access market, cost and performance will determine which technology choice will prevail.

MOCVD growth of InGaAsN QWs and 1.3 /spl mu/m VCSELs

This paper demonstrates MOCVD growth of InGaAsN quantum wells and fabrication of vertical cavity surface emitting lasers (VCSELs). Results on the modulation and high temperature characteristics of 1.3 /spl mu/m-range InGaAsN vertical cavity surface emitting lasers (VCSELs) are also presented. Over 1 mW of single-mode output power is obtained at 80/spl deg/C. Clear eye opening at 2.5 Gb/s and 10 Gb/s are obtained up to 120/spl deg/C and 90/spl deg/C, respectively.

Demonstration of a high-density parallel-WDM optical interconnect

This work presents the first fully-functional 48-channel parallel-wavelength-division-multiplexed (PWDM) transmitter, receiver and link results at a per-channel data rate of 5.21-Gb/s. This high-density PWDM optical interconnect gives an aggregate link bandwidth of a quarter terabit per second.

Self-aligned, buried heterostructure AlInGaAs laser diodesby micro-selective-area epitaxy

We describe the growth and characteristics of AlInGaAs, self-aligned buried heterostructure quantum well lasers deposited by micro-selective-area growth. The lateral waveguide is defined by metalorganic vapor-phase epitaxy in narrow stripe openings; and the natural tendency to form smooth, no-growth {111} sidewall planes produces a low-loss, single-mode waveguide. By proper adjustment of the growth conditions after the waveguide formation, the waveguide may be buried in p-type InP. A buried heterostructure (BH) laser is there formed in a single growth step, eliminating the deterioration associated with air exposure and etch damage, especially for AlInGaAs active regions. The AlInGaAs BH lasers formed in this simple manner exhibit good performance characteristics, with room-temperature threshold current of 4mA.