Micromachined AlGaAs/GaAs vertical cavity filterwithadjustable temperature dependence and wavelength trimming ability

Amano

Furukawa

et al. 2000

Jpn. J. Appl. Phys.

We propose a micromachined vertical cavity resonator enabling temperature insensitive operation for surface emitting lasers or optical add/drop filters. The strain-induced displacement from differential thermal expansion is used to compensate the wavelength shift caused by temperature variation. Also, a wavelength-trimming technology using the same principle with precise strain control is suggested. The possibility of a drastic reduction in the temperature sensitivity of wavelengths, as well as precise wavelength adjustment, is presented. We fabricated a micromachined vertical cavity filter with a GaAlAs/GaAs multilayer reflector, which is mechanically tuned by differential thermal expansion. We observed a large negative temperature coefficient of the resonant wavelength. It is demonstrated that its temperature dependence can be widely controlled by the proposed concept. The possibility of temperature-insensitive operation is discussed.

Section: Discussionmentioning

confidence: 99%

“…8,9) The upper and lower DBRs consist of 15.5-pair and 20-pair GaAs/Ga 0.2 Al 0.8 As, respectively. A 1.55-µm-thick Ga 0.02 Al 0.98 As spacer layer is inserted between the upper and lower DBRs.…”

Section: Fabrication and Characterization Of Micromachined Gaalas/gaamentioning

confidence: 99%

Micromachined Semiconductor Vertical Cavity for Temperature Insensitive Surface Emitting Lasers and Optical Filters

Amano

Furukawa

et al. 2000

Jpn. J. Appl. Phys.

“…Micro-electro-mechanical system (MEMS) filters with various tuning methods and material systems have been reported by several laboratories. [1][2][3][4] However, micromachined tunable filters for use in WDM networks still have not been available because conventional micromachined filters consist of a single cavity that provides the transmission spectra expressed by a Lorentzian function, resulting in a high interchannel crosstalk and a poor contrast.…”

Section: Introductionmentioning

confidence: 99%

Design, Fabrication, and Characterization of Tunable Micromachined Filter with Double-Cavity Structure

Janto

Matsutani

2006

Jpn. J. Appl. Phys.

The image quality of proton radiography using the method of beam energy modulation was studied to look into its practical uses. Two different depth-dose distributions generated by modulation were applied to investigate their effects on the density and spatial resolutions of the radiographic image. A steeper slope was found to provide higher resolution for the matching thickness of a phantom. The image was taken on a scintillation screen, and the distance between the phantom and the screen was a sensitive parameter on the resolution. For a beam with a range of 1.2 cm in Lucite, high-resolution images were attainable in the whole range. The resolution of proton images for different kinds of phantoms was examined in comparison with x-ray images as well as images simulated by a Monte Carlo code MCNPX. For a longer range of 18 cm, images attained by simulations indicated that density resolution is better maintained compared to spatial resolution, which is deteriorated by multiple Coulomb scattering.

“…We can expect various unique features in the proposed tunable devices [4][5][6][7][8], which include wavelength temperature insensitive operation, multiple-wavelength array integration, thermal wavelength tuning with a low tuning voltage, and so on [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Micromachined vertical cavities and hollow optical waveguides for widely tunable devices

2003

SPIE Proceedings

We present the design and fabrication of micromachined vertical cavity filters with stress control, which give us novel functions including temperature insensitive operation, thermal wavelength tuning, wavelength trimming and 2-D multi-wavelength integration. The temperature dependence could be freely controlled either for temperature insensitive operations or for widely wavelength tuning.In addition, we propose the use of a hollow waveguide in which light can be confined in air for realizing temperature-insensitive waveguide devices. We present various unique features in hollow waveguides and the combination with microelectro-mechanical system (MEMS) gives us novel widely tunable waveguide devices.