Method and apparatus including improved vertical-cavity surface-emitting lasers

Abstract

VCSELs and methods having improved characteristics. In some embodiments, these include a semiconductor substrate; a vertical-cavity surface-emitting laser (VCSEL) on the substrate; a first electrical contact formed on the VCSEL; a second electrical contact formed on the substrate, wherein the VCSEL includes: a first resonating cavity having first and second mirrors, at least one of which partially transmits light incident on that mirror, wherein the first second mirrors are electrically conductive. A first layer is between the first mirror and the second mirror and has a first aperture that restricts the path of current flow. A second layer is between the first layer and the second mirror and also restricts the electrical current path. A multiple-quantum-well (MQW) structure is between the first mirror and the second mirror, wherein the first and second apertures act together to define a path geometry of the current through the MQW structure.

What is claimed is: 
     
         1 - 21 . (canceled) 
     
     
         22 . An apparatus comprising:
 a semiconductor substrate;   a vertical-cavity surface-emitting laser (VCSEL) formed on the substrate, wherein the VCSEL includes:
 a first mirror structure; 
 a second mirror structure; 
 at least a first aluminum-containing layer and a second aluminum-containing layer between the first and second mirror structures; and 
 a multiple-quantum-well (MQW) structure between the first and second mirror aluminum-containing layers, the MQW structure comprising one or more GaInP quantum wells; 
   wherein an emission wavelength of the VCSEL is greater than 700 nm.   
     
     
         23 . The apparatus of  claim 22 , wherein the MQW structure comprises GaInAlP barrier layers interposed between the one or more GaInP quantum wells. 
     
     
         24 . The apparatus of  claim 22 , wherein the first and second aluminum-containing layers are AlGaInP layers. 
     
     
         25 . The apparatus of  claim 22 , wherein at least one of the first and second mirror structures comprises a plurality of layers. 
     
     
         26 . The apparatus of  claim 25 , wherein each of the first and second mirror structures comprises a plurality of layers. 
     
     
         27 . The apparatus of  claim 26 , wherein each layer of the first and second mirror structures has a thickness of a quarter-wavelength optical thickness of the emission wavelength of the VCSEL. 
     
     
         28 . The apparatus of  claim 26 , wherein the first and second mirror structures are distributed Bragg reflector (DBR) mirror structures. 
     
     
         29 . The apparatus of  claim 26 , wherein the layers of one of the first and second mirror structures are doped to be of n-type conductivity and the layers of the other of the first and second mirror structures are doped to be of p-type conductivity. 
     
     
         30 . The apparatus of  claim 26 , wherein the plurality of layers comprise alternating layers of differing compositions of AlGaAs having different indexes of refraction. 
     
     
         31 . The apparatus of  claim 28 , wherein at least one of the first and second mirror structures comprises a graded spacer layer between at least one pair of adjacent alternating layers. 
     
     
         32 . The apparatus of  claim 30 , wherein at least one of the first and second mirror structures comprises a graded spacer layer between at least one pair of adjacent alternating layers, the graded spacer layer formed such that aluminum and gallium distributions of the graded spacer layer is monotonically mole-fraction graded over a thickness of the graded spacer layer to match the gallium content in the adjacent alternating layers. 
     
     
         33 . An apparatus comprising:
 a semiconductor substrate;   a vertical-cavity surface-emitting laser (VCSEL) formed on the substrate, wherein the VCSEL includes:
 a first mirror structure; 
 a second mirror structure; and 
 a multiple-quantum-well (MQW) structure between the first and second mirror structures; 
   wherein at least one of the first and second mirror structures comprises alternating layers of InP and InGaAs.   
     
     
         34 . The apparatus of  claim 33 , wherein each of the first and second mirror structures comprises alternating layers of InP and InGaAs. 
     
     
         35 . The apparatus of  claim 34 , wherein each of the first and second mirror structures comprises a graded spacer layer of InGaAsP between at least one pair of adjacent alternating layers. 
     
     
         36 . The apparatus of  claim 33 , wherein the VCSEL is configured to emit a laser-light signal having a wavelength of greater than 1700 nm.