Katsumi Kishino

Wavelength variation of 1.6 µm wavelength buried heterostructure GaInAsP/InP lasers due to direct modulation

Wavelength shift during the period of direct modulation (dynamic wavelength shift) for injection lasers having a BH structure has been investigated both experimentally and theoretically. A GaInAsP/InP BH laser emitting a nominal wavelength of 1.61 μm was modulated by a sinusoidal current at frequencies in the range of 0.2-2 GHz. The full width of the dynamic wavelength shift was 0.35 nm at a modulation frequency of 1.8 GHz, and a modulation depth of 63 percent at a bias current 1.14 times the threshold current. It was found that the width of the dynamic wavelength shift increases with proportion to the modulation depth, and with inverse proportion to the bias current at a frequency below 1 GHZ. The differential coefficientdn/dNof refractive indexnfor carrier densityNin the active region was measured for the purpose of the analysis. The value obtained is-1.2 times 10^{-20}cm3. The dynamic shift of the lasing wavelength was found to be characteristic of the change of the refractive index induced by the oscillation of carrier density in the active region during intensity modulation. The theoretical shift shows maximum value at a resonance-like modulation frequency. The peak height of the resonance wavelength shift is strongly affected by carrier diffusion in the transverse direction, and has a minimum value when stripe width is nearly equal to carrier diffusion length.

Fabrication and lasing properties of mesa substrate buried heterostructure GaInAsP/InP lasers at 1.3 µm wavelength

Fabrication and lasing properties of novel GaInAsP/InP injection lasers at 1.3 μm, with buried heterostructure grown on mesa substrate and fabricated by single-step crystal growth are reported. In this mesa substrate buried heterostructure (MSB) laser, the GaInAsP active layer was grown separately on the top of a mesa structure formed along the surface of a

Chapter 4 Dynamic Single-Mode Semiconductor Lasers with a Distributed Reflector

Publisher Summary This chapter discusses the progress of dynamic single-mode (DSM) lasers and the basic principles and conditions of DSM operation are given. The structure and basis of lasing properties are detailed, in which the coupling problems between the active and passive regions, the coupling parameters, the reflectivity of the distributed reflector, the lasing threshold condition, and the theoretical static- and dynamic-lasing properties are discussed. DSM lasers can be applied to other fields such as optical video disks, fiber gyroscopes, and optical measurements. To optimize the distributed-Bragg-reflector (DBR) and distributed-feedback lasers (DFB), it is necessary to know various physical parameters such as details of the wavelength dependence of refractive index of Ga x In 1–x As y P 1–y . Therefore, further study and development of DSM lasers are very essential in future. Monolithic integration of optical devices and optical circuits can also be accelerated by DBR and DFB-integrated lasers developed for the DSM laser.