1.55 μm InGaAsP/InP laser buried in a high-resistivity epitaxiallayer on a semi-insulating InP substrate

A buried heterostructure (BH) 1.55 μm laser embedded in a high resistivity epitaxial layer on a semi-insulating substrate is described. This device has a planar surface and both a p- and an n-type electrode on the same side, facilitating integration of electronic devices. Its threshold current is typically 9 mA. Its small signal 3 dB modulation bandwidth was 14 GHz due to the reduction of device resistance and capacitance. No degradation was observed in an aging test at 50°C even after more than 3000 h     

Reliability and degradation behaviors of semi-insulating Fe-doped InP buried heterostructure lasers fabricated by movpe and dry etching technique

We clarified the degradation behavior of semi-insulating buried heterostructure lasers in which mesa structures were fabricated by RIE and then buried by MOVPE. The degradation rate and mode correlated with the quality of the BH interface. Based on the correlation, a condition for highly stable SIBH lasers was demonstrated and confirmed experimentally and statistically.     

GaxIn1-xAsyP1-y/InP injection laser partially loaded with first-order distributed Bragg reflector

GaInAsP/InP distributed Bragg reflector (DBR) lasers with a first-order grating were demonstrated experimentally for the first time at a wavelength of 1.3 μm. Single longitudinal mode oscillation was obtained at low temperature, and the temperature dependence of the lasing wavelength was 0.7-0.8 Å/deg. The equivalent refractive index of GaInAsP at the lasing wavelength of 1.3 μm was 3.50 at 186 K.     

New 1.6 ?m wavelength GaInAsP/InP buried heterostructure lasers

1.6 ?m wavelength GaInAsP/InP buried heterostructure (b.h.) lasers were fabricated by a new process. The low threshold of 25 mA was obtained for a cavity length of about 300 ?m and stripe width of 3?5 ?m. Room temperature c.w. operation was also obtained with the threshold of 37 mA. Transverse single-mode operation up to more than three times the threshold was obtained.     

HEAT AND MASS TRANSFER WITH POLYCONDENSATION IN RESIN FILM DURING DRYING

ABSTRACT

In a drying process of dielectric resin films coated on electric conductive substances, phenomena such as polymerization of monomers, by-products yield, shrinkage and stress generation lake place simultaneously in addition to heat and mass transfer. For the enhancement of the drying with high efficiency and high quality, it is important to understand the drying mechanism. In this paper, the characteristics of heat and mass transfer in the resin film including polycondensation reaction are presented. The apparent drying rate of polyamideimide varnish films was measured in two different heating modes of radiation and convection. The reaction rate of polycondensation was analyzed both by the thermogravimetry and the differential scanning calorimetry. The apparent drying rate began to drop remarkably when the reaction rate became significant. It implies that the diffusion of the solvent is inhibited by skinning at the surface. Applying the Vrentas/Duda free-volume diffusion model to the prediction of diffusivity, the heat and mass transfer in the resin film were analyzed theoretically with a reasonable accuracy.     

Longitudinal mode behaviors of 1.5 µm range GaInAsP/InP distributed feedback lasers

Longitudinal mode behaviors of asymmetric structure distributed feedback buried heterostructure (DFB-BH) lasers are examined theoretically and experimentally. A 1.5 μm range GaInAsP/InP DFB-BH laser was fabricated by a three-step LPE growth process. We measured the stopband in the spectrum of the DFB laser. It was found that no resonance mode emission occurred in the gain spectrum and its spectrum was asymmetric with respect to the Bragg wavelength. Most of the lasing power concentrated on the DFB mode adjacent to the stop-band which was determined by the Bragg condition. The measured spectrum was explained by the calculated results of the coupled wave theory with external reflectors. The asymmetric spectrum was caused by the relative position of the cleaved facet on the corrugation grating. It was shown that the asymmetric structure DFB laser, which consisted of two end facets with different reflection coefficients, gives a stable single longitudinal mode. There was no mode jump up to 2.3 times threshold. At a modulation depth of 100 percent, the ratio of the highest nonlasing mode intensity to the lasing DFB mode was estimated to be -16.0 dB.