High-speed directly modulated distributed feedback laser based on detuned loading and photon-photon resonance effect

A monolithic integrated two-section distributed feedback(TS-DFB)semiconductor laser for high-speed direct modulation is proposed and analyzed theoretically.The grating structure of the TS-DFB laser is designed by the reconstructionequivalent-chirp(REC)technique,which can reduce the manufacturing cost and difficulty,and achieve high wavelength controlling accuracy.The detuned loading effect and the photon-photon resonance(PPR)effect are utilized to enhance the modulation bandwidth of the TS-DFB laser,exceeding 37 GHz,while that of the conventional one-section DFB laser is only 16 GHz.When the bit rate of the non-return-to-zero(NRZ)signal reaches 55 Gb/s,a clear eye diagram with large opening can still be obtained.These results show that the proposed method can enhance the modulation bandwidth of DFB laser significantly.

Study on Effect of Anxious Emotion of the Female Who Enter IVF-ET Treatment Cycle on Treatment Outcome

Objective To detect effect of anxious emotion of the female who enter IVF-ET treatment cycle on treatment outcome.Methods Ninety infertilio, women who joined in IVF-ET treatment were collected and they were tested with the State-Trait Anxiety Form at the day entering treatment cycle, with State Anxiety Form at 1 h before oocyte retrieval and 12 d after ET waiting for blood β-hCG result.Results The average of trait anxiety score （38.5） was used to divide patients into two groups. There were significant differences in state anxiety at the first and second test points between high score group （39.9 ± 7.8, 41.5 ± 11.2） and low score group （33.1 ±6.9, 33.7 ±8.1）, but there was no difference at the third point. At three test points, the changes of state anxiety in high-trait anxiety score group showed no difference, but in low-trait anxiety score group there was higher level at the third point than at the first point （38.4 ± 10.6 vs 32.7 ±7.4）（P〈0.05）. Compared variables of psychology, the results demonstrated that trait anxiety, score of success group （β-hCG〉 25 IU/L 12 d after IVF-ET） was higher than that of failure group （40.9 ± 9.2 vs 36.8 ± 7.6）（P〈0.05）.Conclusion Trait anxiety, may be one of mental influential factors on treatment outcome.

1.3-μm 4×25-Gb/s hybrid integrated TOSA and ROSA

The design and fabrication of a compact and low-cost 4×25-Gb/s transmitter optical sub-assembly(TOSA) and receiver optical sub-assembly(ROSA) using a hybrid integrated technique are reported. TOSA and ROSA are developed without thermoelectric cooler for coarse wavelength division multiplexing applications. Physical dimension of the packaged optical subassembly is limited to 11.5 mm×5.4 mm×5.4 mm. The design of TOSA and ROSA is employed using a silica-based arrayed waveguide grating chip to select the specific channel wavelength at O-band. In TOSA, the wavelength of four 1.3-μm discrete directly modulated laser chips is well controlled based on the reconstruction equivalent chirp technique. In the back-to-back transmission test, bit error rates for all lanes of cascade of the TOSA and ROSA are small. A clear opening eye diagram is obtained.