All issues
Volume 28, Issue 4
Displaying 1-11 of 11 articles from this issue
- |<
- <
- 1
- >
- >|
-
Takeshi KAMIYA2000 Volume 28 Issue 4 Pages 201
Published: April 15, 2000
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSDownload PDF (167K) -
Hirofumi KAN2000 Volume 28 Issue 4 Pages 202
Published: April 15, 2000
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSDownload PDF (156K) -
Toshiro HAYAKAWA2000 Volume 28 Issue 4 Pages 203-208
Published: April 15, 2000
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSBasic technology and its progress in broad-area high power laser diodes are reviewed. Brief overview of research history and overall technology have been presented. Recent progress of Al-free active region lasers and broad waveguide structure in our laboratory is described in detail. In addition to the low surface recombination velocity of Al-free materials, optimization of the waveguide thickness in broad waveguide structure has lead to reliable operation of 50-μm wide stripe lasers at 1.5 W and 70°C.View full abstractDownload PDF (1024K) -
2000 Volume 28 Issue 4 Pages 208-208,220
Published: April 15, 2000
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSDownload PDF (777K) -
Hiroshi TAKIGAWA, Yuji NISHIKAWA2000 Volume 28 Issue 4 Pages 209-213
Published: April 15, 2000
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSThis paper reviews techniques to improve the optical output power density and reliability of high-power laser diode arrays. Architecture and performance of monolithic laser diode (LD) bars and LD stacks are described. In addition, packaging and cooling technologies which are essential to LD stacks with high average power densities are discussed.View full abstractDownload PDF (1678K) -
Fumihiko KANNARI, Yuko KONO2000 Volume 28 Issue 4 Pages 214-220
Published: April 15, 2000
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSCharacteristics of lateral phase control with a Talbot self-imaging cavity, which can offer lateral coherence among array type semiconductor lasers, is described. A Talbot cavity with a 1/4 Talbot distance can select a highest array mode, which is characterized by a double peak far-field pattern. So far, the number of broad area diodes that are coherently coupled with the highest array mode is limited around 10. Precise management of emission characteristics of emitters in arrays, and optimization of array fill factors could increase the number of phased arrays, resulting in higher brightness in the far-field.View full abstractDownload PDF (1261K) -
Hiromitsu ASAI2000 Volume 28 Issue 4 Pages 221-225
Published: April 15, 2000
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSThis paper reviews recent activities of quantum cascade lasers in research of mid and far infrared (>μm) semiconductor lasers. The quantum cascade laser has unique characteristics, such as tailored lasing wavelength from mid to far infrared regions and apparent quantum efficiency exceeding 100%, due to the light emitting mechanism based on the sequential steps of the transitions between artificially created subband levels in semiconductor quantum wells. We discuss the lasing mechanism, the specific performance, and the future potentiality of this new type of mid and far infrared semiconductor lasers.View full abstractDownload PDF (940K) -
Masamichi SAKAMOTO2000 Volume 28 Issue 4 Pages 226-230
Published: April 15, 2000
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSApplications of high-power laser diodes in the telecommunications and printing areas are reviewed . Specifically, the following lasers are reviewed: 980 nm laser diodes for EDFAs, Raman Fiber Lasers for Raman amplifiers, 830 nm fiber coupled multi-mode laser diodes for external drum printing, and Fiber Lasers for internal drum printing applications.View full abstractDownload PDF (890K) -
Kazuhiko HARA, Ichiro KOBAYASHI, Ichiro YAMASAKI2000 Volume 28 Issue 4 Pages 231-235
Published: April 15, 2000
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSWe have developed optical fibers with an antireflection coating on the output end of the fiber for a copper vapor laser and have carried out experimental estimation of the characteristics. The used coating material are HfO2 and SiO2. The core diameter of the fiber is 0.6mm and 1.0mm. The reflectance of the coating at 511nm is 0.2-0.6%. The damage threshold was determined at a laser power density of above 35 kWatt/cm2 (7.3J/cm2 at 4.8kHz). We could use the coated fibers to transmit a copper vapor laser-beam for dye laser pumping. In that case the maximum laser power in one fiber was up to 100 Watt. During 100 hours operation there was no damage and little decreasing transmittance of the coated fibers.View full abstractDownload PDF (1022K) -
Taku SAIKI, Tadashi KANABE, Hisanori FUJITA, Masahiro NAKATSUKA, Sadao ...2000 Volume 28 Issue 4 Pages 236-242
Published: April 15, 2000
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSThe multi-pass laser amplifier has been often used as the final power amplification stage in the high peakpower laser systems. The Amplified Spontaneous Emission (ASE) at such a strongly pumped laser generally results in a parasitic oscillation that limits a high gain operation of the amplifier. The three dimensional propagation of the finite-band-width ASE from laser glasses has been calculated for a 30-m long Cassegranian 3-pass disk amplifiers of 35-cm clear aperture. The computational code includes the temporal behavier of flashlamp pumping, the gain reduction in a laser disk due to ASE generation, the long-path back-and-force propagation of ASE between Cassegranian mirrors, and the reduction effect on ASE of spatial filter installed after the amplifier. The ASE energy and its profile have been compared for the on-axis and off-axis arrangement of Cassegranian optics, and also z-pass geometries for three pass configuration. The off-axis alignment of the mirror pairs is very preferable to reduce ASE to one hundredth level than that appeared in the on-axis geometry.View full abstractDownload PDF (1264K) -
Hideyuki NASU, Kaoru SUZUKI, Noriyuki AOKI2000 Volume 28 Issue 4 Pages 243-248
Published: April 15, 2000
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSWe theoretically considered suitable configurations of a fiber grating laser (FGL) to be used in wavelength division multiplexing (WDM) systems. We focused on the effect of composite reflectors where the effect of the front facet of a semiconductor optical amplifier (SOA) is especially significant. We simulated relaxation oscillation frequency and optical power to determine a configuration enabling high bit rates, up to 2.5 Gbit/s. After arriving at a suitable configuration, a packaged FGL has been fabricated. This laser achieves higher output power than any previously reported, and the potential for a rate of 2.5 Gbit/s was confirmed. Compared with a typical 1.55 μm MQW DFB laser, the lasing wavelength temperature dependence is less than half that of a DFB laser. As frequency chirping is remarkably reduced, the power penalty of the FGL is 3 times smaller than that of a DFB laser in transmission experiment with SMF of 70 km.View full abstractDownload PDF (916K)
- |<
- <
- 1
- >
- >|