In this paper, we present the development and performance of a 940nm multimode VCSEL with 3-dB small-signal modulation bandwidth exceeding 25GHz over temperature and relative intensity noise (RIN) below -145dB/Hz, suitable for 100Gb/s per lane data transmission. The VCSEL's 940nm center wavelength. What are Vertical Cavity Surface-emitting Lasers? VCSELs are semiconductor lasers, more specifically laser diodes with a monolithic laser resonator, where the emitted light leaves the device in a direction perpendicular to the chip surface. These include: These features make VCSELs better suited to a wide range of applications than conventional edge-emitting diode lasers and LEDs.