The SLD1550S-A2 from Thorlabs Inc is a Superluminescent Diode with Wavelength 1520 to 1580 nm, Output Power 2 to 2.5 mW, Bandwidth (FWHM) 85 to 90 nm, Forward Voltage 1.6 to 2 V, Operating Current 550 to 600 mA. More details for SLD1550S-A2 can be seen below.