An EDFA with integrated input and output modules is presented. The integrated
input module has a packaged pump laser diode mounted to the metal EDFA package
to provide a heat sink for the pump laser diode which sends the pump laser light
over a optical fiber section connected to the amplifying erbium-doped optical fiber
section. The fiber section is formed from an optical fiber which better matches
the transmission modes in the erbium-doped optical fiber section and has an end
subsection of the single mode fiber for a larger numerical aperture. Collimating
lenses also increase the coupling efficiency of the laser diode to the erbium-doped
fiber section. The integrated output module has a photodiode with a tap filter
to monitor the output power of the EDFA, an optical isolator to prevent interference
in the erbium-doped optical fiber section. With a twin optical isolator, the integrated
input and output modules can be arranged in different ways and combinations with
the erbium-doped optical fiber section. The resulting EDFAs can be manufactured
relatively inexpensively into an very small packages compared to current EDFA packages.
