摘要:

Very low loss GaAs/AlGaAs miniature bending waveguides with curvature radii less than 1 mm have been fabricated. Their propagation characteristics have been measured at wavelengths of 1.30 and 1.55 &mgr;m. Total loss of the fabricated S‐bending waveguide shows no increase due to radiation loss even at small radii less than 1 mm. The measured total loss at a radius of 500 &mgr;m, for example, is 0.55 and 1.4 dB at wavelengths of 1.30 and 1.55 &mgr;m, respectively. These very low loss bending waveguides with small radii prove to be suitable for compact optical integrated circuits.

ISSN:0003-6951    

DOI:10.1063/1.101223

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

We demonstrate a new method to measure the nonlinear damping factor in 1.5 &mgr;m distributed feedback lasers from the phase difference between FM and AM signals due to carrier density modulation. The damping factor is found to have the same linear relation to the square of the resonance frequency for devices having different wavelength detuning.

ISSN:0003-6951    

DOI:10.1063/1.101225

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Time and space domain holography by persistent spectral hole burning in photochemically active media is shown to permit storage, recall, and conjugation of temporal profiles of light signals as short as 100 fs. This limit for the temporal resolution is set by the finite spectral width of the impurity absorption bands of presently available recording materials.

ISSN:0003-6951    

DOI:10.1063/1.101226

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

In this letter we describe the operation of a new high‐speed, high‐gain amorphous silicon sensor. The device gain originates from the photoconductive properties of amorphous silicon but good light to dark sensitivity is obtained by suppressing the sensor dark current by means of a lightlyp‐type barrier layer. Optical gains in excess of 100 have been achieved with response times of approximately 200 &mgr;s.

ISSN:0003-6951    

DOI:10.1063/1.101200

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Guided wave surface polaritons (GWSPs) propagating in a dielectric slab adjacent to a metal surface are investigated both theoretically and experimentally. It is shown that GWSPs can be used for high‐resolution analysis of dielectric surfaces by means of the well‐known attenuated total reflectance technique. From our experimental results we conclude that changes in the system equivalent to the adsorption of 1/30 of a monolayer can easily be resolved. A well‐established surface characterization method, which had been restricted to few systems up to now, is thus immensely generalized.

ISSN:0003-6951    

DOI:10.1063/1.101201

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Excimer lasers excited by electron or ion beams having energy deposition of 100’s J/lover many microseconds experience a temperature rise of hundreds of degrees (K). The increase in gas temperature may greatly impact both the kinetics and spectroscopic parameters. In this letter we discuss the high‐temperature (≤900 K) plasma kinetics and absorption in He and Ne buffered gas mixtures for particle beam pumped XeF lasers. We find both gain and absorption depend differently on gas temperature in these mixtures (absorption decreasing in He mixtures, increasing in Ne mixtures). The differences are attributed to a reduction in diatomic absorbing species with increasing temperature and differences in the temperature dependence of the optical absorption cross sections for NeXe+and Xe+2.

ISSN:0003-6951    

DOI:10.1063/1.101241

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

A new technique is demonstrated for the formation of narrow active regions in quantum well lasers. In temperature engineered growth (TEG), the substrate temperature is varied during the growth of epitaxial layers by metalorganic chemical vapor deposition (MOCVD) on nonplanar substrates, allowing two‐dimensional control of device features. Buried heterostructure designs with submicron active region stripe widths are obtained without the need for fine process control of lateral dimensions. The contact area above the active region is coplanar with the surrounding surface and wide enough to allow easy contacting and heat sinking. Carrier confinement is accomplished by lateral thickness variation of the quantum well active region resulting in a local strip of minimum band gap. Lasers grown in this manner exhibit cw threshold currents as low as 3.8 mA (3.4 mA pulsed), having an as‐grown active region width of 0.5 &mgr;m. The near‐field optical profile indicates stable, single transverse mode operation and minimal current leakage in these devices.

ISSN:0003-6951    

DOI:10.1063/1.101242

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

A buried crescent InGaAsP/InP laser with a double active layer was fabricated. The laser showed very high characteristic temperatureT0and highly nonlinear light versus current characteristics. A theoretical model using a rate equation approach showed good agreement with the experimental results.

ISSN:0003-6951    

DOI:10.1063/1.101243

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

The temporal profiles of harmonic cross phase modulation pulses from 500 to 570 nm generated in ZnSe by a 1054 nm picosecond pulse have been observed and theoretically modeled. The pulse shape of these harmonic‐modulated pulses is accounted for by the interference and induced phase matching of the harmonic generated waves in ZnSe by cross phase modulation.

ISSN:0003-6951    

DOI:10.1063/1.101244

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

We have fabricated an integrated 1.5 &mgr;m distributed feedback laser (DFB) with a Y‐branching waveguide and a monitoring photodetector, grown entirely by metalorganic chemical vapor deposition. The integrated device is designed to resolve the frontface‐backface mistracking problem of the DFB laser and to demonstrate monolithic integration of fundamental building blocks for photonic integrated circuits.

ISSN:0003-6951    

DOI:10.1063/1.101245

出版商:AIP    

年代:1989

数据来源: AIP