| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical fiber amplifier and an optical fiber type amplifier which enable amplification of signal light with low excitation power and ease of incidence of the signal light. SOLUTION: An optical fiber of an optical fiber amplifier 120 is formed by a pumping light core 54 as a first core of a center portion, a second core 50 provided around the pumping light core 54 and having a refractive index lower than the pumping light core 54, and a cladding 52 provided around the second core 50 and having a refractive index lower than the second core 50. Pumping light 302 propagates within the pumping light core 54 and excites an optical amplifying section 56 as an optical amplification medium contained in the pumping light core 54. A signal light 300 is propagated through the second core 50 and is amplified by the excited optical amplifying section 56. Thus, the signal light 300 may be amplified with a low excitation power, and incidence of the signal light 300 may be facilitated. |
