High-power cw vertical-cavity top surface-emitting GaAs quantum well lasers

Abstract

We have devised a novel vertical-cavity top surface-emitting GaAs quantum well laser structure which operates at 0.84 μm. The laser combines peripheral current injection with efficient heat removal and uses only the epitaxially grown semiconductor layers for the output mirrors. The structure is obtained by a patterned deep H+ implantation and anneal cycle which maintains surface conductivity while burying a high resistance layer. Peripheral injection of current occurs from the metallized contact area into the nonimplanted nonmetallized emission window. For 10-μm-diam emitting windows, ∼4 mA thresholds with continuous-wave (cw) room-temperature output powers ≳1.5 mW are obtained. Larger diameter emitting windows have maximum cw output powers greater than 3 mW. These are the highest cw powers achieved to date in current injected vertical-cavity surface-emitting lasers.

VCSEL Fundamentals

“…2.2, several methods have been successfully employed to achieve current confinement to a predefined active area. Among those are simple mesa etching of the top mirror [13,17] (often called air-post VCSELs), ion implantation (predominantly using protons) to create highly resistive semiconductor regions [14,15], or selective lateral oxidation [18] of a some 10 nm thick semiconductor layer with high aluminum content like Al 0.98 Ga 0.02 As or even AlAs. Mesa etching incurs scattering losses of the optical field and may cause reliability problems if the active region is exposed to air.…”

“…VCSELs were first commercially offered by Honeywell in 1996. As a result of standardization, these first-generation lasers were made from GaAs-AlGaAs mixed compound semiconductors for emission close to 850 nm and relied on proton implantation [14,15] for current confinement. During the years to follow, in particular 1999-2002, many companies were founded, aiming to capitalize on the enormous projected growth in the optical datacom and telecom markets.…”

Development of a high-power vertical-cavity surface-emitting laser array with ion-implanted current apertures

“…In spite of the fact, the detailed characteristics of the ion-implanted VCSELs had been researched only in ten milliwattclass output power 13,14 . In this paper, we report on development of a high power VCSEL with proton-implanted current aperture.…”

Many-valley electron transport in AlGaAs VCSELs

“…This issue arises from the potential barriers at the heterointerfaces, which are also the main cause of self-heating in VCSELs. In the early '90s, several solutions such as modulation doping [4] or AlGaAs intermediate layers [5,6] were proposed. These approaches were not decisive, since they were temperaturedependent or did not provide an adequate reduction of the series resistance.…”