Naoto Jikutani

Threshold Current Density Analysis of Highly Strained GaInNAs Multiple Quantum Well Lasers Grown By Metalorganic Chemical Vapor Deposition

Highly strained GaInAs/GaAs quantum wells (QWs) [single quantum well (SQW), double quantum well (DQW) and triple quantum well (TQW)] are grown by metalorganic chemical vapor deposition (MOCVD), and GaInNAs/GaAs lasers (SQW and TQW) are fabricated with different numbers of wells to investigate their characteristics. The low threshold current density of 541 A/cm2 and the lasing wavelength of 1.276 µm are obtained by the SQW laser with cavity length of 2070 µm. The threshold current density of 1.41 kA/cm2 and the lasing wavelength of 1.296 µm are obtained by the TQW laser with cavity length of 1140 µm under pulsed operation at room temperature. From the threshold current density analysis, it is evident that their crystal growth and fabrication are successful. The threshold current density of the vertical cavity surface-emitting laser (VCSEL) is also discussed.

780nm-range VCSEL array for laser printer system and other applications at Ricoh

A 780 nm-range 40 channels vertical-cavity surface-emitting laser (VCSEL) array was developed as a writing light source for printers. A 15° off missoriented GaAs substrate, an aluminum-free GaInAsP/GaInP compressively-strained multiple quantum well and an anisotropic-shape transverse-mode filter were employed to control polarization characteristics. The anisotropic-shape transverse-mode filter also suppressed higher transverse-mode and enabled high-power single-mode operation. Thus, orthogonal-polarization suppression-ratio (OPSR) of over 22 dB and side-mode suppression-ratio (SMSR) of 30 dB were obtained at operation power of 3mW at same time for wide oxide-aperture range below 50 μm2. Moreover, a thermal resistance was reduced for 38% by increasing a thickness of high thermal conductivity layer (3λ/4-AlAs layer) near a cavity. By this structure, a peak-power increased to 1.3 times. Moreover, a power-fall caused by self-heating at pulse-rise was decreased to 10% and the one caused by a thermal-crosstalk between channels was decreased to 46%. The VCSEL array was mounted in a ceramic package with a tilted seal glass to prevent optical-crosstalk caused by other channels. Thus, we achieved stable-output and high-quality beam characteristics for long-duration pulse drive.

MOCVD grown GaInNAs lasers

Summary form only given. We demonstrated the first electrically pumped CW operation of a 1.26 /spl mu/m MOCVD grown GaInNAs VCSEL. Thus far this is the only report of an electrically pumped GalnNAs VCSEL grown by MOCVD, which is suitable for mass production. The threshold current and voltage of a 10 /spl times/ 10 /spl mu/m/sup 2/ aperture device under CW operation were 7.6 mA and 2.8 V, respectively. Highly strained GaInAs QWs were grown by MOCVD. We report the well number dependence of the photoluminescence (PL) and laser characteristics of highly strained GaIn(N)As MQWs. We also discuss the possibility of applying them to 1.3 /spl mu/m GaInNAs VCSELs. The PL intensity versus the PL peak wavelength of the GaInAs QWs is shown. The high luminescence intensities were obtained up to 1.20 /spl mu/m, 1.18 /spl mu/m and 1.17 /spl mu/m in the SQW, DQW and TQW, respectively.

Well number dependence of highly strained GaIn(N)As MQW structures by metalorganic chemical vapor deposition

Highly strained GaInAs/GaAs MQWs (SQW, DQW, TQW) were grown by MOCVD and highly strained GaInNAs/GaAs lasers (SQW, TQW) grown by MOCVD were fabricated to evaluate their characteristics difference by well number. A low threshold current density of 541 A/cm/sup 2/ and a lasing wavelength of 1.276 /spl mu/m were obtained in a 2070 /spl mu/m-cavity length SQW laser. A threshold current density of 1.46 k A/cm/sup 2/ and a lasing wavelength of 1.296 /spl mu/m were obtained in a 1140 /spl mu/m-cavity length TQW laser under pulse operation at room temperature.