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Showing papers on "Microheater published in 1992"


Journal ArticleDOI
TL;DR: In this article, a novel fiber tapering process using a microheater is proposed and fiber couplers have been fabricated by means of this method, which is excellent for producing a 12.4mm-wide, stable heat region controlled by applied current.
Abstract: A novel fiber tapering process using a microheater is proposed and fiber couplers have been fabricated by means of this method. This heater is excellent for producing a 12.4-mm-wide, stable heat region controlled by applied current. Wavelength-flattened couplers with very low losses are fabricated. Taper slope angles are far more gradual than that obtained by stationary burner flames, and the length of the fiber region deformed by tapering is 11.8 mm. The average excess loss at 1.31 and 1.55 mu m is 0.13 dB with a maximum value of 0.3 dB. >

27 citations


Journal ArticleDOI
TL;DR: In this paper, a microheater made of heavily Boron doped single crystal Si beam covered with SiO 2 film, 1000×300×3 μm, is fabricated on the n type Si substrate by the anisotropic etching technique.
Abstract: Microheater made of heavily Boron doped single crystal Si beam covered with SiO 2 film, 1000×300×3 μm, is fabricated on the n type Si substrate by the anisotropic etching technique. As this microheater has an air bridge structure of low resistivity semiconductor material with positive but small temperature coefficient of resistance, a broad heating area up to 800 °C is easily obtained and it has quick response with the thermal time constant t of about 4 ms and has small power consumption. Since this heating area is made of p type layer in the n type substrate,this area can be electrically isolated from the substrate because of the formation of p-n junction.

13 citations


01 Jan 1992
TL;DR: In this paper, a microheater was fabricated on a thermally isolated silicon (Si) membrane and its electrical and thermomechanical properties were assessed, which was adjusted for good thermal isolation and good resistance to thermal shock.
Abstract: A microheater was fabricated on a thermally isolated silicon (Si) membrane and its electrical and thermomechanical properties were assessed. The sensor design was adjusted for good thermal isolation and good resistance to thermal shock. The heater was a platinum (Pt) thin-film meandering filament deposited with electron beam evaporation and patterned with lift-off methods. In order to operate the heater at high temperatures with minimum loss of Pt by evaporation, the heater was encapsulated with a ceramic film. During the heater operation, most of the heat was dissipated via conduction through the Si membrane which supported the multi-layered heater. When the Si membrane was completely etched away to suspend the heater, the power needed to heat the filament to strong incandescence (about 700-800°C) was 110 mW. Structural failure was not observed when the device was subjected to thermocycling up to approximately 500°C. The importance of the thermomechanical match of layers in a multi-layered heater structure, especially for use at high temperatures, is addressed.

9 citations


Journal ArticleDOI
TL;DR: In this article, a microheater was fabricated on a thermally isolated silicon (Si) membrane and its electrical and thermomechanical properties were assessed, which was adjusted for good thermal isolation and good resistance to thermal shock.
Abstract: A microheater was fabricated on a thermally isolated silicon (Si) membrane and its electrical and thermomechanical properties were assessed. The sensor design was adjusted for good thermal isolation and good resistance to thermal shock. The heater was a platinum (Pt) thin-film meandering filament deposited with electron beam evaporation and patterned with lift-off methods. In order to operate the heater at high temperatures with minimum loss of Pt by evaporation, the heater was encapsulated with a ceramic film. During the heater operation, most of the heat was dissipated via conduction through the Si membrane which supported the multi-layered heater. When the Si membrane was completely etched away to suspend the heater, the power needed to heat the filament to strong incandescence (about 700-800°C) was 110 mW. Structural failure was not observed when the device was subjected to thermocycling up to approximately 500°C. The importance of the thermomechanical match of layers in a multi-layered heater structure, especially for use at high temperatures, is addressed.

3 citations


Journal ArticleDOI
TL;DR: In this paper, a widely tunable, power-controlled oscillation method of AlGaAs semiconductor lasers in the visible region, based on temperature modulation by a microheater placed on the laser chip, is described.
Abstract: We describe a widely tunable, power-controlled oscillation method of AlGaAs semiconductor lasers in the visible region, based on temperature modulation by a microheater placed on the laser chip. The continuous frequency tuning range for a single-axial-mode operation is extended to 0.28 nm (132 GHz) at 779 nm by the heater current modulation. Cutoff frequency of the temperature modulation response is 50 Hz. The injection current is used mainly for the power control of the FM oscillation. By using a short external mirror for axial mode selection, the continuous tuning range is further increased to 0.49 nm (237 GHz), which corresponds to almost five times the value with the injection current modulation.

2 citations


Patent
04 Mar 1992
TL;DR: In this paper, the authors measured the heat conductivity of a thin film by placing heat sources between the thin film and its substrate at constant intervals and measuring the temperature variation of the surface of the thin material while the heat sources generate heat periodically.
Abstract: PURPOSE:To measure the heat conductivity of a thin film by arranging heat sources between the thin film and its substrate at constant intervals and measuring the temperature variation of the surface of the thin film while the heat sources generate heat periodically. CONSTITUTION:The microheaters 3 are embedded between the substrate 2 and thin film 1 to be measured at the constant gap intervals and generate heat at a specific period to separate thermal influence between the thin film 1 and substrate 2; and a radiation thermometer is used to measure the phases of temperature amplitudes on the gaps of the heaters embedded in the surface of the thin film 1, the phase difference from the phase of microheater heating is found to calculate heat diffusivity from the phase difference, and the result is multiplied by heat capacity per unit volume of the thin film 1 to find the heat conductivity from a specific expression. Consequently, the heat conductivity of the thin film which can not be present as a single layer can accurately be measured.

2 citations