摘要:

The fabrication and operation of the first cleaved‐coupled‐cavity (C3) semiconductor lasers with large cavity length ratios are described. The internal cleaved facet is precisely positioned by photochemically etching a groove through most of the wafer. Single longitudinal mode operation is obtained over a temperature range of 21 °C and over a current range of threshold to greater than four times threshold. Sidemode suppression of 100:1 was measured when the laser was modulated at 350 MHz with an extinction ratio greater than 10:1. These results are experimentally and theoretically compared to approximately equal length C3lasers.

ISSN:0003-6951    

DOI:10.1063/1.94952

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

The stimulated emission from lasers with a linear light‐current characteristic is polarized in the TE mode. For some lasers with a kink in theL‐Icurve, the kink represents the onset of a higher order TM polarized stimulated emission. Both TE and TM modes are present above the kink. These TE and TM emissions usually have separate groups of longitudinal modes. Under pulsed operation, the TE mode appears before the TM mode. X‐ray diffraction measurements suggest the presence of an internal stress in lasers exhibiting stimulated TM emission. A possible explanation for the observation is discussed. The mechanism is based on (i) higher optical gain of the TM mode than that of the TE mode in the presence of a compressive stress and (ii) larger reflectivity of the higher order TM modes. The power output at which a kink appears can be increased by decreasing the active layer width.

ISSN:0003-6951    

DOI:10.1063/1.94953

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

We report our observations attributable to optical gain through stimulated emission in the violet when sodium vapor is optically pumped with the 350.7‐nm line of a krypton ion laser. In addition we present the accompanying fluorescence spectrum which shows previously unreported discrete structure on the short wavelength side of the violet bands.

ISSN:0003-6951    

DOI:10.1063/1.94954

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

A new numerical approach is outlined to the problem of calculating the normal modes of electromagnetic wave propagation in a graded‐index planar optical waveguide. The method is versatile, directed at the type of refractive‐index profile produced by ion implantation, and promises to facilitate the investigation of multiregion problems.

ISSN:0003-6951    

DOI:10.1063/1.94955

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

The dispersion relations for waves guided by thin dielectric films surrounded on one or both sides by media with intensity‐dependent refractive indices are solved numerically. A number of new modes as well new features in the usual low power modes are predicted.

ISSN:0003-6951    

DOI:10.1063/1.94956

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

We describe measurements of pulses consisting of only eight optical periods. The pulses were produced by compression with a short optical fiber and a grating pair. Measurement was by autocorrelation using noncollinear second harmonic generation in a thin crystal of potassium dihydrogen phosphate.

ISSN:0003-6951    

DOI:10.1063/1.94957

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

We present here the first simple double‐heterostructure channeled‐substrate laser with lateral index guiding grown by molecular beam epitaxy. The channel is along [110] direction. The threshold current is 60 mA. Linear light‐current relation and stable far‐field patterns have been observed over the range of currents tested (from 60 to 160 mA). The lasers operate in single longitudinal mode over a wide range of current. The intensity ratio of the dominant mode and the neighboring mode is greater than 100:1.

ISSN:0003-6951    

DOI:10.1063/1.94941

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

It is suggested that the lasing frequency of GaAs‐GaAlAs quantum well lasers can be tuned when the quantum well structure is irradiated with a pulsed low‐energy long‐wavelength laser. This new tuning mechanism is based on the decrease of the electron binding energy, in the well, with increasing intensity of the external laser field. Typically, 0.60 mJ of 10.6‐&mgr;m radiation in a 1‐ns pulse may blue‐shift the quantum well laser frequency by approximately 20 nm.

ISSN:0003-6951    

DOI:10.1063/1.94942

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

The effects of external optical feedback on the spectral properties of cleaved‐coupled‐cavity (C3) single mode lasers have been investigated. cw mode rejection ratios and intensity dropout rates have been measured at different optical feedback strengths. The study shows some individual variations in sensitivity to optical feedback between lasers of the same structure. Optical feedback as small as −22 dB can cause a significant number of intensity dropouts from the main lasing mode in some units whereas other units can tolerate a −15 dB optical feedback without causing dropouts or degradation in the mode rejection ratio. By taking some simple steps in preventing reflections in fiber optic systems, it is shown that even the most sensitive C3laser can be operated without penalty due to optical feedback. cleaved‐coupled‐cavity semiconductor lasers

ISSN:0003-6951    

DOI:10.1063/1.94943

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

A technique was developed and used to measure the rotatory power of 90° twisted nematic liquid crystals in the visible and infrared spectral regions. Experimental results for two liquid crystal mixtures, BDH‐E7 and ZLI‐1132, are in very good agreement with theoretical calculations for a wide spectral range and for different liquid crystal thicknesses. A quantitative relationship between liquid crystal birefringence, wavelength, and cell thickness was derived for use in the design of IR liquid crystal light valves with high contrast ratios and minimum response times.

ISSN:0003-6951    

DOI:10.1063/1.94944

出版商:AIP    

年代:1984

数据来源: AIP