RESUMEN
We experimentally demonstrate an all-fiber high-power fiber amplifier with high beam quality and a slope efficiency of 81.8%, using a fiber-Bragg-grating-stabilized laser diode as a narrow spectral linewidth (0.08 nm) seed source. During amplification, the spectral linewidth of the laser output is broadened from 0.08 to 0.24 nm due to nonlinear phenomena. To the best of our knowledge, we report the first experimental observation of the suppression of stimulated Brillouin scattering (SBS), with increased output power. In addition, we investigated the SBS suppression by simultaneously measuring the optical backscattered power, backscattered spectrum, and output spectrum at different values of output power. The beam quality, M2, was measured to be â¼1.28 at the maximum output power of 2.05 kW, and modal instability was not observed.
RESUMEN
RATIONALE: Thoracic disc herniation (TDH) is an infrequent spinal disease and difficult to treat well. Various surgical approaches and procedures were introduced in many literatures. The authors report a patient with dorsal migrated TDH compressing the spinal cord at T10-11 level. PATIENT CONCERNS: A 65-year-old male patient presented with complaints of severe paresthesia of both legs and progressive motor weakness for 1 week. DIAGNOSES: Magnetic resonance imaging (MRI) of the thoracic and lumbar spine revealed TDH and migration of dorsal side on spinal cord at T10-11 level. INTERVENTIONS: Successful decompressive surgery was performed through a posterior interlaminar approach using only endoscopic instruments. OUTCOMES: After the operation, patient's symptoms, paraparesis and paresthesia, immediately improved. LESSONS: The successful results of this case suggest that full endoscopic laminotomy and discectomy may be an attractive minimally invasive surgical technique for treating TDH with dorsal migrated fragments.