We could have the 30-year anniversary since a VCSEL was invented by Kenichi Iga. We have seen various
applications including datacom, sensors, optical interconnects, spectroscopy, optical storages, printers, laser
displays, laser radar, atomic clock, optical signal processing and so on. A lot of unique features have been shown,
low power consumption, a wafer level testing and so on. In this paper, the brief history and our recent research
activities on VCSEL photonics will be reviewed. We present the wavelength engineering of VCSEL arrays for
use in high speed short-reach systems, which includes the wavelength integration and wavelength control. The
joint research project on ultra-parallel optical links based on VCSEL technologies will be introduced for high
speed LANs of 100Gbps or higher. The small footprint of VCSELs allows us to form a densely packed VCSEL
array both in space and in wavelength. The wavelength engineering of VCSELs may open up ultra-high capacity
networking. Highly controlled multi-wavelength VCSEL array and novel multi-wavelength combiners are
developed toward Tera-bit/s-class ultrahigh capacity parallel optical links. In addition, the MEMS-based VCSEL
technology enables widely tunable operations. We demonstrated an "athermal VCSEL" with avoiding temperature
controllers for uncooled WDM applications. In addition, new functions on VCSELs for optical signal processing
are addressed. We present an optical nonlinear phase shifter based on a VCSEL saturable absorber.
Also, highly reflective periodic mirrors commonly used in VCSELs enables us to manipulate the speed of light.
This new scheme provides us ultra-compact intensity modulators, optical switches and so on for VCSEL-based
photonic integration. Also, this paper explores plasmonic VCSELs.