Читать книгу VCSEL Industry - Babu Dayal Padullaparthi - Страница 35

Stage‐III of VCSEL development started in 1999, shown in Figure 1.12, as we entered a new information and technology era in 2000. The third stage (1999–2010) brought on new development of wavelengths, single mode, VCSEL arrays, volume manufacturing driven by Internet traffic demand, autofocus, and so forth, and the focus has shifted to commercial efforts. Why did 1310–1550 nm VCSELs not become widely adopted? That was primarily due to the technical difficulty of making mirrors and overcoming optical loss in materials.

In 2000 one of the authors (Iga) wrote a VCSEL review paper [49] and in the same special issue, DARPA managers Elias Towe, Robert F. Leheny, and Andrew Yang wrote the following about VCSEL in their review paper [50]: “Its size, manufacturability, and potential ease of heterogeneous integration of electronics promise a range of applications that have yet to be explored.” This was the time when DARPA invested considerable human and monetary resources in the R&D of VCSEL, in particular the massive integration of VCSELs, detectors, micro‐optics and driving electronics for free‐space optical interconnects and all optical switching. However, practical and commercial free‐space interconnect and all optical switching did not really pick up during the subsequent years. This investment nonetheless continued to drive VCSEL innovations such as high‐power VCSEL arrays, high‐contrast gratings, athermal VCSELs, coupled cavity VCSELs, VCSELs‐based slow light waveguide devices, multi‐wavelength VCSELs/WDM [51], quantum dot VCSELs, high‐bandwidth VCSELs (>20 GHz), and so forth.

VCSELs are currently applied in various optical systems, such as optical networks, parallel optical interconnects, laser printers, computer mice, and so on. The three critical application areas that provided the commercial impetus for continued VCSEL expansion were high‐speed data connectivity, computer mice, and laser printing.