Multimode light generating module, semiconductor laser apparatus, and optical fiber amplifier

摘要

A multimode light generating module comprises an optical cavity and a light-receiving element. The optical cavity is constituted by a semiconductor optical amplification element, and an optical fiber having a grating. The optical fiber comprises a grating having an apodized periodic refractive index distribution, and the slope of the reflection spectrum in a longer wavelength region with respect to the peak wavelength lambda_p is gentler than that in the shorter wavelength region therewith. The grating satisfies the relationship of 0.5 nm>lambda_0.2-lambda_p>0.1 nm. Here, lambda_0.2 is defined by lambda_0.2^h-lambda_0.2^l, where lambda_0.2^h is the longer one of two wavelengths exhibiting a relative reflectivity of 0.2 with respect to the maximum reflectivity, and lambda_0.2^l is the shorter one of two wavelengths exhibiting a relative reflectivity of 0.2 with respect to the maximum reflectivity.