Dj. Sadler et al., OPTICAL REFLECTIVITY OF MICROMACHINED (111)-ORIENTED SILICON MIRRORS FOR OPTICAL INPUT-OUTPUT COUPLERS, Journal of micromechanics and microengineering, 7(4), 1997, pp. 263-269
In this work, bulk-micromachined {111}-oriented silicon mirrors at 54.
7 degrees have been fabricated in 20 wt% KOH solution at various tempe
ratures and characterized with single-mode fibers (10/125 and 5/125).
In fabricating the mirrors, the etch rate of the (100) silicon surface
was widely varied from 5.3 to 73 mu m hr(-1) as the-processing temper
atures were varied from 40 to 80 degrees C. In spite of the tremendous
variation of etch rate, the measured reflectivities of the mirrors sh
owed fairly stable values of 63.7-58% at 1330 nm and 55.4-57.7% at 155
0 nm. This paper describes the silicon mirror processing conditions, m
easured reflectivities, reflected beam profiles, and a prototype integ
rated optical I-O coupler with the realized mirrors. The results obtai
ned from this work show that optical I-O couplers with 54.7 degrees mi
rrors on conventional (100)-oriented silicon wafers are feasible, enab
ling us to envisage a synchronized optical clock distribution system a
s well as a distributed remote optical sensing system with low manufac
turing cost.