Abstract: Apparatus and a method are provided for aligning an analog laser transmitter. Operational characteristics of the laser are determined. These characteristics are used to derive the power level required of a communication signal to properly modulate the laser for communication across an optical fiber. The magnitude of an input communication signal is then adjusted to the derived level, and maintained at this level for proper modulation. The alignment is performed upon the replacement of laser components in the field. The alignment may also be periodically effected to compensate for normal degradation of laser components over time.

Abstract: Optical apparatus for performing wavelength-dependent beam combination. The apparatus relies on a polarization beam splitter in combination with other optical elements to develop combined beams with the same polarization type and that are therefore suitable for polarization-dependent combination with other beam arrays. A dichroic mirror, which is used as the wavelength-dependent element of the apparatus, is oriented such that the incident beams are substantially perpendicular to the mirror. With this orientation, the dichroic mirror achieves near-ideal performance even with beam arrays having a substantial angular field. The apparatus also uses two plates which, although designed for operation as quarter-wave plates at one of the two wavelights being combined, are oriented with their respective fast axes substantially perpendicular to each other such that polarization conversions, effected by the plates on beams having the other of the two wavelengths, substantially cancel each other.