Toyoji Chino

Improvement of Coupling Efficiency for Passive Alignment of Stacked Multifiber Tapes to a Vertical-Cavity Surface-Emitting Laser Array

High-efficiency coupling of stacked multifiber tapes to a vertical-cavity surface-emitting laser (VCSEL) array is demonstrated. Three fiber tapes, each of which includes four multimode fibers, are coupled to a 4 x 3 VCSEL array simply by inserting fibers into guiding holes fabricated on the back side of the substrate. Mirrorlike smooth floors of the holes are formed by electron cyclotron resonance reactive ion beam etching, which results in great improvement of coupling efficiency. The average measured coupling efficiency is 81.3%.

Surface-Emitting Laser with a Common-Anode Configuration for Application to the Photonic Parallel Memory

A novel structure of a vertical-cavity surface-emitting laser (VCSEL) was proposed and demonstrated. Using a common-anode configuration, lower mesa height and lower electrical resistance were realized. The threshold current was 6 mA for a 10-µm-diameter device under room-temperature pulsed operation. The lasing wavelength was 939 nm. This configuration is suitable for large-scale integration. We also propose an optoelectronic integrated circuit (OEIC) with the common-anode configuration, which consists of a VCSEL and a heterostructure phototransistor (HPT) for optical parallel processing.