T. Higashi

Experimental analysis of temperature dependence of oscillation wavelength in quantum-well FP semiconductor lasers

We experimentally evaluated the temperature dependence of the oscillation wavelength in 1.3-/spl mu/m GaInAsP-InP strained multiple-quantum-well (MQW) semiconductor lasers compared to bulk lasers. The temperature dependence of the oscillation wavelength can be characterized by two newly introduced coefficients /spl alpha//sub 1/ and /spl alpha//sub 2/ which are the gain peak wavelength shift coefficients under the constant current condition and under the constant temperature condition, respectively. These two coefficients of various MQW structure lasers are the same as those of bulk lasers. This result means that the oscillation wavelength shift coefficient d/spl lambda//dT is only a function of the characteristic temperature T/sub 0/. The higher T/sub 0/ induces the large temperature dependence of the oscillation wavelength, When the characteristic temperature T/sub 0/ is equal to the characteristic temperature T/sub ltr/ of the transparency current I/sub tr/, the oscillation wavelength shift coefficient d/spl lambda//dT takes the maximum value which is determined by the thermally induced bandgap narrowing effect d/spl lambda//sub g//dT. One possibility to solve the paradox between a high characteristic temperature T/sub 0/ and the small temperature dependence of the oscillation wavelength is the introduction of the temperature-independent leakage current.

High-temperature CW operation of InGaAsP-InP semi-insulating buried heterostructure lasers using reactive ion-etching technique

We fabricated 1.5-/spl mu/m semi-insulating buried heterostructure (SI-BH) lasers with InGaAsP-InP strained-layer multiple-quantum wells using a reactive ion etching (RIE) technique for mesa definition. A very high CW operating temperature of 150/spl deg/C was obtained in a 300-/spl mu/m-long laser whose rear facet was HR-coated.<<ETX>>

Optimum asymmetric mirror facet structure for high-efficiency semiconductor lasers

A design theory for asymmetric mirror facet structure lasers that takes into account the spatial hole burning (SHB) effect along the cavity is presented. It is shown that the SHB effect reduces the external quantum efficiency in asymmetric mirror facet structure lasers, and the front facet reflectivity has an optimum value depending on the internal loss for high-efficiency operation. A slope efficiency of more than 50% has been obtained in lasers based on the new design theory. It is noted that nonuniform current injection is one of the most useful methods for increasing the external quantum efficiency, which is reduced by the SHB effect. >

Well-thickness dependence of high-temperature characteristics in 1.3-μm AlGaInAs-InP strained-multiple-quantum-well lasers

Well-thickness dependence of temperature characteristics of 1.3-/spl mu/m AlGaInAs-InP strained-multiple-quantum-well lasers was investigated. Higher characteristic temperatures of threshold current density were obtained for thicker wells up to 6 nm. Fabricated ridge-waveguide lasers with 6-nm-thick wells exhibited characteristic temperature of as high as 125 K. Relaxation-oscillation frequency reduced by only 13% between 25/spl deg/C and 85/spl deg/C.

Polarization dependence of photo-detection in strained multiple quantum-well semiconductor lasers

We investigated polarization dependence of photo-detection in strained layer multiple quantum-well (SL-MQW) lasers for time compressive multiplex (TCM) application. The polarization dependence of SL-MQW lasers is larger than that of bulk lasers because of the quantum effect. To improve the polarization dependence of photo-detection, we theoretically and experimentally analyzed the effect of strain quantity on the polarization dependence, and found that large tensile strained quantum-well structure is suitable for the small polarization independence of 0.8 dB and low threshold current characteristics. Moreover, we achieved smaller polarization dependence less than 0.5 dB by applying reverse bias voltage in the photo-detection mode. >

Temperature dependence of gain characteristics in 1.3-/spl mu/m AlGaInAs/InP compressively strained multiple quantum well semiconductor lasers

Summary form only given. So far 1.3 /spl mu/m AlGaInAs-InP strained MQW lasers have achieved high characteristic temperature T/sub 0/ of 120 K and high operating temperature of 185 C. In this paper, we evaluated temperature dependence of the gain characteristics in AlGaInAs-InP lasers, and found that the high T/sub 0/ was caused by the smaller temperature dependence of the spontaneous emission efficiency than that of GaInAsP-InP lasers.

Temperature sensitivity of oscillation wavelength in 1.3 /spl mu/m-GaInAsP/InP quantum-well semiconductor lasers

Characteristics of optical sources for access networks are required to be insensitive to the environment temperature change. In a relatively long-haul (> 10 km) and high bit-rate (>100Mb/s) transmission system, the effect of dispersion of optical fiber could not be negligible. Therefore, the stability of the oscillation wavelength to the temperature change could also be required. In this paper, we experimentally examined the temperature sensitivity of the oscillation wavelength in 1.3 /spl mu/m GaInAsP-InP QW semiconductor lasers.

1.3 /spl mu/m high T/sub 0/ strained MQW laser with AlGaInAs SCH layers on a hetero-epitaxial InGaAs buffer layer

The 1.3 /spl mu/m InGaP clad laser with AlGaInAs SCH layer was fabricated on a hetero-epitaxial InGaAs QW buffer layer. Due to high optical confinement, this laser showed a high characteristic temperature T/sub 0/ of 110 K.

Experimental analysis of characteristic temperature in quantum-well semiconductor lasers

Temperature dependence of the gain characteristics in a 1.31-/spl mu/m GaInAsP/InP quantum-well laser was measured and compared with that in a 0.98 /spl mu/m GaInAs/GaAs laser. It was found that the low characteristic temperature T/sub 0/ in the 1.31-/spl mu/m laser was determined by the temperature dependence of the transparent current density J/sub tr/.