The SLD1550S-A1 from Thorlabs Inc is a Superluminescent Diode with Wavelength 1520 to 1580 nm, Output Power 0.75 to 1 mW, Bandwidth (FWHM) 100 to 110 nm, Operating Current 450 to 500 mA, Forward Voltage 1.6 to 2 V. More details for SLD1550S-A1 can be seen below.