A far-end measurement instrument for baseband frequency response, based on the swept frequency method, has been designed and constructed. It is important to stabilize modulation frequency characteristics of the laser diode which is significantly affected by externally reflected light to the laser diode. It has been found that by coupling the laser diode to a fiber with obliquely polished end face, the influence of externally reflected light can be negligibly small. Optimum coupling conditions, concerning tilt angle of fiber end and distance between fiber and laser facet are clarified. Moreover, an automatic power control and temperature control circuit has been applied to the laser diode. As a result, sufficient stabilization of modulation frequency characteristics to measure baseband frequency response of graded-index optical fiber has been attained.
|Number of pages||5|
|Journal||Transactions of the Institute of Electronics and Communication Engineers of Japan. Section E|
|Publication status||Published - 1981 Jan 1|
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