Geometrical tolerance of optical fiber and laser diode for passive alignment using LTCC technology

The upsurge in the demand for high capacity communication links results in a rapid growth in the field of optical fiber communication. Recent advances in satellite communications urge for the transmission of high-frequency signals with minimal losses, and it is regarded that radio-over-fiber is the solution for such broadband analog applications. Considering the many advantages offered by low-temperature co-fired ceramics multilayer technology, it is promising to use this technology for passive alignment of an optical fiber to a laser diode, eventually hybrid-integrated with an electro-optical modulator for microwave frequencies. In this paper, we analyzed the necessity of efficient coupling of optical power into the fiber in an optical link, based on intensity modulation and direct detection. We also estimated the alignment tolerance as +/-20 μm, which can be realized exploiting recent advances of the ceramic multilayer technology.