There are two types of optics for coupling a laser diode (LD) to an optical fiber: optics with a hemispherical-ended fiber, and with a discrete lens. The latter has the great advantage in alignment of the optics and the hermetic seal of the LD, but it Is difficult to develop a low-aberration lens to get high efficiency. We have realized very low-aberration optics with a truncated Si spherical lens. The Si crystal has good transparency in the 1.2-10-μm wavelength region and a high refractive index (n = 3.5), so this is suitable for low-aberratin lens material.
© 1985 Optical Society of AmericaPDF Article