METHOD FOR MEASURING MODE DISTRIBUTION CHARACTERISTIC OF SEMICONDUCTOR LASER

摘要

PURPOSE:To obtain a k-value under a condition near to a use state by using a high sensitivity frequency region method and subjecting a semiconductor laser diode to NRZ modulation on the basis of a PN pulse pattern to measure the k-value showing a mode distribution characteristic. CONSTITUTION:A semiconductor laser diode (LD) is subjected to NRZ modulation on the basis of a PN series pulse and the relative intensity of the light output of the LD is measured with respect to at least one vertical mode. Next, a linear frequency spectrum component is measured with respect to said vertical mode and the continuous frequency spectrum of the whole of a measuring system containing the LD is measured with respect to the linear frequency spectrum component. Subsequently, by measuring the continuous frequency spectrum component of the measuring system itself, the continuous frequency component of the LD itself is measured. From these measured values a k-value showing a mode distribution characteristic is calculated.