InGaAsP double heterostructure lasers (λ=1.3 μm) with etched reflectors

Abstract

Discrete InGaAsP double heterostructure lasers (λ=1.3 μm) have been fabricated by a novel batch process which incorporates chemically etched end reflectors. The etched-mirror lasers have threshold current densities as low as 3.5 kA/cm2. The average threshold current density for the etched-mirror lasers is approxiamtely 40% higher than for standard cleaved-mirror devices fabricated from the same wafer. The laser fabrication process permits batch fabrication of a much wider variety of discrete laser geometries than conventional laser-cleaving techniques.

High-efficiency stripe-geometry InGaAsP DH lasers (λ = 1.3 µm) with chemically-etched mirrors

“…Subsequent photolithographic steps are used to define Si3N4 masks (150pm x 300pm) aligned over the AuZn contact stripes. As in previous work[2]…”

“…Recent results for InGaAsP DH lasers (x -1.3 pm) with one chemically-etched mirror and one cleaved mirror indicated that external differential quantum efficiencies of 2.3-4.50'10 (from the cleaved-mirror) could be obtained [3]. In the present work we have fabricated stripe-geometry InGaAsP DH lasers (X = 1.3 pm) with two chemicallyetched mirrors using the mirror-etching procedure described previously [2]. This etching procedure permits the fabrication of laser mirrors which are very smooth and near vertical, and thus have high reflectivity and low scattering loss.…”

“…3) batch processing of lasers subsequent to mirror formation, and many others, as discussed prevjously [2]. To date it has been difficult -to realize significant advantage from etched-mirror DH lasers due to the difficulty of obtaining mirrors of high reflectivity and low scattering loss.…”

“…olo Br in methanol solution. The preferential etching characteristics of this etchant for InP and InGaAsP have been described before [2] and result in isotropically-etched laser mirrors and preferentially-etched laser sidewalls. Furthermore, extremely smooth mirrors are obtained which permit very high external differential quantum efficiencies to be achieved.…”

“…The excellent performance of the etched-mirror lasers described here represents significant progress toward the fabrication of integrated electro-optical components. Progress has been made also toward realizing significant advantage from etched-mirror DH lasers such as in the fabrication of very short lasers with very low threshold currents and single longitudinal mode operation, and the use of batch processing to form many complete lasers on a common substrate [2]. Other applications such as the sumultaneous fabrication of an on-chip monitoring detector have also been suggested [21*…”