Single-mode fiber packaging for semiconductor optical devices

An approach is described that increases package assembly alignment tolerances substantially while demonstrating coupling efficiencies as high as 40% on the bench and 25% in the package. Since working distances inside the package of 2-4 mm allow for the insertion of some microoptics, a spherical lens was used to couple from the device into single-mode fiber. The ball lens is mounted directly on the chip carrier for maximum thermal and mechanical stability and is aligned mechanically rather than actively. The single-mode fiber alignment is done actively and the fiber positioned to compensate for misalignments both directly and by using a second lens affixed to the end of the fiber. The optical characteristics of the devices are discussed. Alignment tolerance tradeoffs are discussed. Results of bench measurements are given