摘要:

It is shown that a 39 fs output pulse from a colliding‐pulse mode‐locked cw dye laser is directly compressed to 22 fs, without amplification, using a highly nonlinear 4‐(N, N‐dimethylamino)‐3‐acetamidonitrobenzene single‐crystal cored fiber followed by a dispersive delay line of a grating pair.

ISSN:0003-6951    

DOI:10.1063/1.104767

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We present and demonstrate a self‐transverse‐mode organization effect (passive transverse mode locking?) in a cavity that contains a saturable absorber. It gives narrowing and filamentation of the oscillating beam in the region of the absorber. In the demonstration, we have used a resonator formed by two photorefractive phase conjugate mirrors. The saturable absorber was bacteriorhodopsin in a polymer film. Light powers of 1–100 mW were used.

ISSN:0003-6951    

DOI:10.1063/1.104768

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We report blue light generation in a LiTaO3waveguide by quasi‐phase‐matched (QPM) second‐harmonic generation (SHG). A periodically domain‐inverted structure for QPM is fabricated in LiTaO3by proton exchange of a selective Ta‐masked area using pyrophosphoric acid followed by heat treatment. By utilizing this structure and low‐loss proton‐exhanged waveguides, we have realized a third‐order QPM‐SHG device. As a result, 0.13 mW of harmonic blue light was generated for a conversion efficiency of 18%/W.

ISSN:0003-6951    

DOI:10.1063/1.104769

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Controllable enhancement of excitonic spontaneous emission is demonstrated with the tuning of emission wavelength by electric fields applied to GaAs single quantum wells located inside half‐wavelength microcavities at low temperature, ∼50 K. Radiation patterns of the spontaneous emission from the microcavities, containing the quantum wells are found to be well controlled by the electric fields.

ISSN:0003-6951    

DOI:10.1063/1.104770

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

The sign of the strain in a multiquantum well (MQW) active layer of an InGaAs/InP laser determines whether lasing occurs from the electron–heavy hole transition or from the electron‐light hole transition. Lasing from the electron‐light hole transition is reported to provide a much better performance than predicted by theory. It is concluded that this gives the best device performance, providing a higher differential gain, a lower threshold current, a record low linewidth enhancement factor of 1.5, and a K factor of 0.22 ns, potentially allowing a 3 dB modulation bandwidth of 40 GHz.

ISSN:0003-6951    

DOI:10.1063/1.104771

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

The dielectric constants &egr; of LaAlO3, NdGaCO3and MgO substrates were measured using a dielectric filled resonant cavity. Precise values of &egr; were obtained for NdGaO3and MgO. An inhomogeneous dielectric constant was observed for LaAlO3. Optical studies indicated that the extensive twinning in this material was the source of the inhomogeneity.

ISSN:0003-6951    

DOI:10.1063/1.104772

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We have fabricated and characterized the first GexSi1−xoptical directional couplers. These structures were fabricated from GexSi1−xgrown by rapid thermal processing chemical vapor deposition. The average attenuation of single, straight waveguide sections was 3.3 dB/cm at a wavelength of 1.52 &mgr;m. For the directional couplers, the coupling coefficient was 3.9 cm−1for a waveguide separation of 1.5 &mgr;m.

ISSN:0003-6951    

DOI:10.1063/1.104773

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Using a novel technique, we are able to controllably switch the polarization of microchip lasers in under 5 &mgr;s. The technique is applicable to a broad variety of lasers and theoretical modeling indicates that switching rates of several megahertz are possible.

ISSN:0003-6951    

DOI:10.1063/1.105229

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We demonstrate vertical integration of InGaAs mesa photodiodes with InGaAsP rib waveguides employing an intermediate optical impedance matching layer. The diode length necessary for 90% light absorption at 1.52 &mgr;m wavelength was 42 &mgr;m, a threefold reduction in diode length with respect to previous work employing similar waveguides without a matching layer. The quantum efficiency was observed to be almost independent of the optical wavelength and polarization. The influence of spatial transient intensity redistribution effects on these devices is investigated in detail.

ISSN:0003-6951    

DOI:10.1063/1.104774

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

The operation of ultralow threshold current GaAs and InGaAs quantum well lasers at cryogenic temperatures has been studied. In particular the threshold currentIthand lasing wavelength of GaAs and strained InGaAs lasers have been measured as a function of temperature from 300 down to 5 K.Ithcan in both lasers be characterized by a linear function of temperature up to 200 K, with a significantly (2.5×) largerdIth/dTfor the GaAs laser. We measured a minimum threshold current of 120 &mgr;A for the GaAs laser and 165 &mgr;A for the InGaAs laser at 5 K. We derive a simple expression for the transparency carrier density as a function of temperature and effective masses to explain our results.

ISSN:0003-6951    

DOI:10.1063/1.104775

出版商:AIP    

年代:1991

数据来源: AIP