摘要:

The nonamplified spontaneous emission of AlGaAs single quantum well graded index separate confinement heterostructure laser diodes has been measured for photon energies between 1.35 and 2.05 eV and at pump currents up to 19 kA cm−2and optical flux densities up to 35 MW cm−2. The spectra are very complex and we observe the following three features. First, the spontaneous emission intensity increases slowly with current, even above threshold. Second, the carrier temperature increases slightly above the lattice temperature, 28 K at a pump rate of 1.5×1029cm−3s−1. Third, at high power densities the high‐energy spontaneous emission at a photon energy of 1.9 eV increases dramatically.

ISSN:0003-6951    

DOI:10.1063/1.105856

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

In a parabolic quantum well, the shift in optical transition energy due to the quantum confined Stark effect is independent of the carrier effective mass. This fact enables us to realize polarization‐independent optical waveguide intensity switches with high on/off ratio. An absorption‐type switch with GaAs/Al0.3Ga0.7As equivalent parabolic quantum wells is fabricated with molecular beam epitaxy. Both transverse‐electric and transverse‐magnetic mode lights exhibit an on/off ratio of 27.6 dB at an applied voltage of 6.84 V at 850 nm wavelength. To our knowledge, this is the first polarization‐independent optical waveguide intensity switch based on the electric‐field‐induced effect in the semiconductor quantum well.

ISSN:0003-6951    

DOI:10.1063/1.105857

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We report on the first room‐temperature operation of aluminum‐free In0.2Ga0.8As/GaAs/ In0.49Ga0.51P multiple‐quantum‐well lasers grown by gas‐source molecular beam epitaxy. These lasers have low threshold current densityJthof 177 A/cm2, high internal quantum efficiency of 91%, and low internal waveguide loss of 9.1 cm−1. The characteristic temperatureT0is 150 K, which is the highest value ever reported. These results demonstrate that gas‐source molecular beam epitaxy is suitable for growing high‐quality In0.2Ga0.8As/GaAs/In0.49Ga0.51P lasers.

ISSN:0003-6951    

DOI:10.1063/1.105858

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

High‐temperature operation of the InGaAs/GaAs/AlGaAs quantum well lasers with an expanded vertical optical mode is demonstrated for the first time using a periodic index separate confinement heterostructure (PINSCH) laser. Continuous wave (cw) operation up to 145 °C is achieved with a coated 3 &mgr;m×508 &mgr;m PINSCH laser. The measured characteristic temperature (170 K) and external differential quantum efficiency (0.75 mW/mA) are comparable to those obtained in a graded index separate confinement heterostructure laser fabricated at the same time. These results illustrate the excellent capability of the PINSCH laser to compress the transverse beam divergence without sacrificing the electrical carrier confinement.

ISSN:0003-6951    

DOI:10.1063/1.105859

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We have used molecular beam epitaxy to grow at 500 °C a graded InAlGaAs superlattice structure sandwiched by two heavily doped window layers which are directly connected to the gate and source of a discrete field‐effect transistor (FET). Upon band‐gap illumination, a steady‐state photovoltage controllable by the light intensity is generated by the superlattice structure, which then modulates the drain current of the FET to the same amount as does a dc voltage source. The intrinsic response time of the photovoltaic effect is on the order of picoseconds, thus the modulation speed on the drain current is completely limited by the FET.

ISSN:0003-6951    

DOI:10.1063/1.105860

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We have demonstrated high‐power linear arrays of InGaAs/InGaAsP grating‐surface‐emitting lasers operating at a wavelength of 1.5 &mgr;m and emitting over 200 mW cw and 400 mW pulsed power. Arrays 1 cm in length exhibit coherent, mutual‐injection‐coupled laser action; single‐wavelength‐mode operation with a linewidth of 100 MHz at a power output of 55 mW has been observed.

ISSN:0003-6951    

DOI:10.1063/1.105861

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

An electro‐optic measuring technique is reported by which higher‐order susceptibilities of nonlinear optical polymer films can be determined. The basis of the evaluation is the separation of linear and quadratic electro‐optic effects by means of a dc and ac modulated electric field in the experiment. The method is demonstrated with results for an unpoled and a poled polymer film.

ISSN:0003-6951    

DOI:10.1063/1.105862

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We examine the dependence upon unpumped length of the lasing threshold current in partially pumped InGaAs/AlGaAs graded index, separate confinement heterojunction lasers and demonstrate the tunability of our devices using current injection into the previously unpumped section.

ISSN:0003-6951    

DOI:10.1063/1.105863

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

An all‐optical serial‐to‐parallel conversion technique, which is the inverse process of the real‐time pulse shaping, is reported. A conversion of 0.14‐Tbits/s signals using excitonic‐giant nonlinearity of ZnSe film is reported. The response of this conversion system is faster than 13 ps with a conversion efficiency of 0.1%.

ISSN:0003-6951    

DOI:10.1063/1.105864

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

A novel scheme using second‐order‐optical nonlinear effects for optical time‐division demultiplexing is proposed. This scheme is all‐optical, and has potential bandwidth on the order of tera (1012) Hz. A prototype demultiplexer using this scheme has been demonstrated, achieving bit rate capacity of 100 Gb/s and crosstalk of −20 dB. This scheme could be realized in a compact form with further advances in nonlinear‐waveguide devices and high‐peak power semiconductor lasers.

ISSN:0003-6951    

DOI:10.1063/1.105865

出版商:AIP    

年代:1991

数据来源: AIP