The ideal light source for datanets

Overcoming limitations in semiconductor alloy design

“…Such frustrations impose severe penalties in device design. An example of this is the technologically important field of vertical cavity surface emitting lasers (VCSELs) used for fiber optic communications [3]. The difficulty with Bragg mirror stacks of quaternary alloys grown on InP substrates lies in their poor thermal conductivity.…”

“…Although high-reflectivity AlAs/GaAs Bragg mirror stacks can readily be grown on GaAs substrates, it is not possible to find an alloy for the active region of the VCSEL with a band gap near 0.8 or 0.95 eV and which is lattice matched to GaAs. To grow such VCSELs, it has thus been necessary to resort to complicated techniques which often involve 'lift-off' and 'fusion bonding' steps in the laser fabrication process [3]. Another alloy constraint example is the quadruple junction solar cell where the optimal heterostructure for realizing a 40% efficient solar cell would be comprised of light absorbing semiconductor active regions grown epitaxially with the sequence of band gaps 0.67/1.05/1.42/1.9 eV on a Ge substrate [4].…”

Equivalency-processing parallel photonic integrated circuit (EP^3IC): equivalence search module based on multiwavelength guided-wave technology

“…The first of these concepts is based on what are known as smart pixels. 1,2 By use of rudimentary electronic logic for processing and optical sources and detectors for communication, arrays of smart pixels have the capacity for the parallel manipulation of large data sets. The second concept to emerge is called the photonic processor.…”

Harnessing light for high-power applications

“…3 VCSELs' rise to fame originated in low-power (a few milliwatts) telecom and datanet applications during the mid-1990s. 4 This success was mainly due to the lasers' lower manufacturing costs and higher reliability compared to edge emitters.…”