Mode-selective amplification in a large mode area Yb-doped fiber using a photonic lantern.

We demonstrate selective spatial mode amplification in a few mode, double-clad Yb-doped large mode area (LMA) fiber, utilizing an all-fiber photonic lantern. Amplification to multi-watt output power is achieved while preserving high spatial mode selectivity. We observe gain values of over 12 dB for all modes: LP01, LP11a, and LP11b, when amplified individually. Additionally, we investigate the simultaneous amplification of LP01+LP11a and LP11a+LP11b, and the resultant mode competition. The proposed architecture allows for the reconfigurable excitation of spatial modes in the LMA fiber amplifiers, and represents a promising method that could enable dynamic spatial mode control in high power fiber lasers.

Fiber chirped pulse amplifier at 2.08 µm emitting 383-fs pulses at 10 nJ and 7 MHz.

An all-polarization maintaining (PM) fiber chirped pulse amplifier system at 2.08 µm based on thulium:holmium codoped gain fibers is reported. An inhouse built oscillator emits pulses at a repetition rate of 7 MHz with a spectral full width at half-maximum (FWHM) bandwidth of 23.5 nm at 2.8 mW average output power. The pulses are temporally stretched and subsequently amplified in a double-stage amplifier setup. The stretched pulses are compressed to 383 fs by use of a Martinez-style setup at an output pulse energy of 10.2 nJ. By neglecting temporal stretching, high peak powers in a single amplifier stage led to Raman soliton formation at 2.3 µm.

Gadopentetate dimeglumine excretion into human breast milk during lactation.

PURPOSE: To analyze the amount of gadopentetate dimeglumine excreted into human breast milk following intravenous injection of a clinical dose. MATERIALS AND METHODS: Gadopentetate dimeglumine was injected intravenously in 20 lactating women (23-38 years of age). Breast-feeding was interrupted for at least 24 hours. Serial samples of expressed milk were collected and analyzed for gadolinium concentration by means of inductively coupled plasma atomic emission spectrometry at a wavelength of 342.247 nm. RESULTS: The cumulative amount of gadolinium excreted in human breast milk during 24 hours was 0.57 micromol +/- 0.71 (SD; range, 0.05-3.0 micromol). The excreted dose was thus less than 0.04% of the administered intravenous dose (range, 0.001%-0.04%; mean, 0.009% +/- 0.010) for all cases. CONCLUSION: Less than 0.04% of administered gadopentetate dimeglumine is excreted into human breast milk. The amount transferred to a nursing infant orally would be far more than 100 times less than the permitted intravenous dose (200 micromol per kilogram of body weight) for neonates. The recommendation of a 24-hour suspension of breast-feeding for lactating women should thus be reconsidered.

[Status of the fallopian tube following pelviscopic surgery (conventional versus laser) of tubal pregnancy]. / Tubenzustand nach pelviskopisch operierter (konventionell versus Laser) Tubargravidität.

From 1984 to 1988, 136 patients with ectopic pregnancy were treated by endoscopic means. In 29 cases the fallopian tube was removed. In 107 patients conservative treatment was undertaken. The salpingotomy was performed with the endocoagulator and with scissors or using lasers. The postoperative status of the tube was controlled in 54 patients by hysterosalpingography (n = 17) or by second-look laparoscopy (n = 37). In 38 cases the patency test was positive. The incidence of postoperative adhesions was minimal after laser salpingotomy (16%). The complication rate was low (2%).