Abstract: A wavelength-tunable vertical-cavity surface-emitting laser (VCSEL) with the use of micro-electromechanical system (MEMS) technology is provided as a swept source for Optical Coherence Tomography (OCT). The wavelength-tunable VCSEL comprises a bottom mirror of the VCSEL, an active region, and a MEMS tunable upper mirror movable by electrostatic deflections. The bottom mirror comprising a GaAs based distributed Bragg reflector (DBR) stack, and the active region comprising multiple stacks of GaAs based quantum dot (QD) layers, are epitaxially grown on a GaAs substrate. The MEMS tunable upper mirror includes a membrane part supported by suspension beams, and an upper mirror comprising a dielectric DBR stack. The MEMS tunable quantum dots VCSEL can cover an operating wavelength range of more than 100 nm, preferably with a center wavelength between 250 and 1950 nm, and the sweeping rate can be from a few kHz to hundreds of kHz, and up to a few MHz.

Abstract: A wavelength-tunable vertical-cavity surface-emitting laser (VCSEL) with the use of microelectromechanical system (MEMS) technology is provided as a swept source for Optical Coherence Tomography (OCT). The wavelength-tunable VCSEL comprises a bottom mirror of the VCSEL, an active region, and a MEMS tunable upper mirror movable by electrostatic deflections. The bottom mirror comprising a GaAs based distributed Bragg reflector (DBR) stack, and the active region comprising multiple stacks of GaAs based quantum dot (QD) layers, are epitaxially grown on a GaAs substrate. The MEMS tunable upper mirror includes a membrane part supported by suspension beams, and an upper mirror comprising a dielectric DBR stack. The MEMS tunable quantum dots VCSEL can cover an operating wavelength range of more than 100 nm, preferably with a center wavelength between 250 and 1950 nm, and the sweeping rate can be from a few kHz to hundreds of kHz, and up to a few MHz.

Abstract: A wavelength-tunable vertical-cavity surface-emitting laser (VCSEL) with the use of microelectromechanical system (MEMS) technology is provided as a swept source for Optical Coherence Tomography (OCT). The wavelength-tunable VCSEL comprises a bottom mirror of the VCSEL, an active region, and a MEMS tunable upper mirror movable by electrostatic deflections. The bottom mirror comprising a GaAs based distributed Bragg reflector (DBR) stack, and the active region comprising multiple stacks of GaAs based quantum dot (QD) layers, are epitaxially grown on a GaAs substrate. The MEMS tunable upper mirror includes a membrane part supported by suspension beams, and an upper mirror comprising a dielectric DBR stack. The MEMS tunable quantum dots VCSEL can cover an operating wavelength range of more than 100 nm, preferably with a center wavelength between 250 and 1950 nm, and the sweeping rate can be from a few kHz to hundreds of kHz, and up to a few MHz.

Abstract: A wavelength-tunable vertical-cavity surface-emitting laser (VCSEL) with the use of microelectromechanical system (MEMS) technology is provided as a swept source for Optical Coherence Tomography (OCT). The wavelength-tunable VCSEL comprises a bottom mirror of the VCSEL, an active region, and a MEMS tunable upper mirror movable by electrostatic deflections. The bottom mirror comprising a GaAs based distributed Bragg reflector (DBR) stack, and the active region comprising multiple stacks of GaAs based quantum dot (QD) layers, are epitaxially grown on a GaAs substrate. The MEMS tunable upper mirror includes a membrane part supported by suspension beams, and an upper mirror comprising a dielectric DBR stack. The MEMS tunable quantum dots VCSEL can cover an operating wavelength range of more than 100 nm, preferably with a center wavelength between 250 and 1950 nm, and the sweeping rate can be from a few kHz to hundreds of kHz, and up to a few MHz.

Abstract: A wavelength-tunable vertical-cavity surface-emitting laser (VCSEL) with the use of microelectromechanical system (MEMS) technology is provided as a swept source for Optical Coherence Tomography (OCT). The wavelength-tunable VCSEL comprises a bottom mirror of the VCSEL, an active region, and a MEMS tunable upper mirror movable by electrostatic deflections. The bottom mirror comprising a GaAs based distributed Bragg reflector (DBR) stack, and the active region comprising multiple stacks of GaAs based quantum dot (QD) layers, are epitaxially grown on a GaAs substrate. The MEMS tunable upper mirror includes a membrane part supported by suspension beams, and an upper mirror comprising a dielectric DBR stack. The MEMS tunable quantum dots VCSEL can cover an operating wavelength range of more than 100 nm, preferably with a center wavelength between 250 and 1950 nm, and the sweeping rate can be from a few kHz to hundreds of kHz, and up to a few MHz.

Abstract: A wavelength-tunable vertical-cavity surface-emitting laser (VCSEL) with the use of microelectromechanical system (MEMS) technology is provided as a swept source for Optical Coherence Tomography (OCT). The wavelength-tunable VCSEL comprises a bottom mirror of the VCSEL, an active region, and a MEMS tunable upper mirror movable by electrostatic deflections. The bottom mirror comprising a GaAs based distributed Bragg reflector (DBR) stack, and the active region comprising multiple stacks of GaAs based quantum dot (QD) layers, are epitaxially grown on a GaAs substrate. The MEMS tunable upper mirror includes a membrane part supported by suspension beams, and an upper mirror comprising a dielectric DBR stack. The MEMS tunable quantum dots VCSEL can cover an operating wavelength range of more than 100 nm, preferably with a center wavelength between 250 and 1950 nm, and the sweeping rate can be from a few kHz to hundreds of kHz, and up to a few MHz.

Abstract: A wavelength-tunable vertical-cavity surface-emitting laser (VCSEL) with the use of micro-electromechanical system (MEMS) technology is provided as a swept source for Optical Coherence Tomography (OCT). The wavelength-tunable VCSEL comprises a bottom mirror of the VCSEL, an active region, and a MEMS tunable upper mirror movable by electrostatic deflections. The bottom mirror comprising a GaAs based distributed Bragg reflector (DBR) stack, and the active region comprising multiple stacks of GaAs based quantum dot (QD) layers, are epitaxially grown on a GaAs substrate. The MEMS tunable upper mirror includes a membrane part supported by suspension beams, and an upper mirror comprising a dielectric DBR stack. The MEMS tunable quantum dots VCSEL can cover an operating wavelength range of more than 100 nm, preferably with a center wavelength between 250 and 1950 nm, and the sweeping rate can be from a few kHz to hundreds of kHz, and up to a few MHz.

Abstract: A printed wiring board on which a package to be arranged, including: a first layer that is relatively rigid; and a second layer that is relatively flexible and on which the package is to be soldered, wherein an area other than a package arrangement area of the second layer is joined to the first layer by an adhesion layer.

Abstract: A gain-coupled distributed feedback (DFB) semiconductor laser includes a grating formed by grooves through at least a part of an active region of a laser cavity. The DFB laser may be configured with a substantially pure gain-coupled grating and may be configured to provide facet power asymmetry. The grating may include at least a first-order grating section and a second-order grating section. A lasing wavelength may be obtained at the Bragg wavelength of the second-order grating section by substantially eliminating index coupling in the grating. The first-order grating section may act as a reflector for the lasing wavelength, thereby producing asymmetric power distribution in the laser cavity.

Abstract: A method whereby a compound having HCV replication inhibitory activity and desired optical activity can be synthesized selectively and at high yield in a small number of steps by using a compound having a specific chiral auxiliary as a starting compound is provided. A compound represented by the formula (1-8): wherein Y represents a group represented by the following formula: Q represents a protected carbonyl group; D represents —(CH2)m—R?, etc.; and n represents an integer of 0 to 10.

Abstract: A method whereby a compound having HCV replication inhibitory activity and desired optical activity can be synthesized selectively and at high yield in a small number of steps by using a compound having a specific chiral auxiliary as a starting compound is provided. A compound represented by the formula (1-8): [wherein Y represents a group represented by the following formula: Q represents a protected carbonyl group; D represents —(CH2)m—R?, etc.; and n represents an integer of 0 to 10].

Abstract: A method whereby a compound having HCV replication inhibitory activity and desired optical activity can be synthesized selectively and at high yield in a small number of steps by using a compound having a specific chiral auxiliary as a starting compound is provided. A compound represented by the formula (1-8): wherein Y represents a group represented by the following formula: Q represents a protected carbonyl group; D represents —(CH2)m—R?, etc.; and n represents an integer of 0 to 10.

Abstract: A method whereby a compound having HCV replication inhibitory activity and desired optical activity can be synthesized selectively and at high yield in a small number of steps by using a compound having a specific chiral auxiliary as a starting compound is provided. A compound represented by the formula (1-8): wherein Y represents a group represented by the following formula: Q represents a protected carbonyl group; D represents —(CH2)m—R?, etc.; and n represents an integer of 0 to 10.

Abstract: A printed wiring board on which a package to be arranged, including: a first layer that is relatively rigid; and a second layer that is relatively flexible and on which the package is to be soldered, wherein an area other than a package arrangement area of the second layer is joined to the first layer by an adhesion layer.

Abstract: In general, a complex-coupled distributed feedback (DFB) semiconductor laser includes a grating formed by grooves through at least a part of an active region of a laser cavity. The complex-coupled DFB laser may be configured with a wavelength monitoring section and may be configured to provide facet power asymmetry. The wavelength monitoring section may include a second-order grating section configured to emit radiation (e.g., vertical radiation) from a side of the DFB laser for monitoring.

Abstract: A distributed feedback semiconductor laser may have (1) a controlled complex-coupling coefficient which is not affected by grating etching depth variation, and (2) facet power asymmetry with no facet reflection which eliminates a random effect of facet grating phase. The device comprises a multiple-quantum-well active region, and a complex-coupled grating formed by periodically etching grooves through a part of the active region. The semiconductor materials for a barrier layer where the groove etching is to be stopped, a regrown layer in the etched groove, and a laser cladding layer, are chosen all the same, so as to form an active grating entirely buried in the same material, providing a complex-coupling coefficient which is defined independently of the etching depth. Facet power symmetry may also be provided by composing the laser cavity of two sections (“front” and “back” sections) having different (“front” and “back”) Bragg wavelengths.

Abstract: A gain-coupled distributed feedback (DFB) semiconductor laser includes a grating formed by grooves through at least a part of an active region of a laser cavity. The DFB laser may be configured with a substantially pure gain-coupled grating and may be configured to provide facet power asymmetry. The grating may include at least a first-order grating section and a second-order grating section. A lasing wavelength may be obtained at the Bragg wavelength of the second-order grating section by substantially eliminating index coupling in the grating. The first-order grating section may act as a reflector for the lasing wavelength, thereby producing asymmetric power distribution in the laser cavity.

Abstract: A method whereby a compound having HCV replication inhibitory activity and desired optical activity can be synthesized selectively and at high yield in a small number of steps by using a compound having a specific chiral auxiliary as a starting compound is provided. A compound represented by the formula (1-8): [wherein Y represents a group represented by the following formula: Q represents a protected carbonyl group; D represents —(CH2)m—R?, etc.; and n represents an integer of 0 to 10].

Abstract: In general, a complex-coupled distributed feedback (DFB) semiconductor laser includes a grating formed by grooves through at least a part of an active region of a laser cavity. The complex-coupled DFB laser may be configured with a wavelength monitoring section and may be configured to provide facet power asymmetry. The wavelength monitoring section may include a second-order grating section configured to emit radiation (e.g., vertical radiation) from a side of the DFB laser for monitoring.

Abstract: The invention provides a distributed feedback semiconductor laser, having (1) a controlled complex-coupling coefficient which is not affected by grating etching depth variation, and (2) facet power asymmetry with no facet reflection which eliminates a random effect of facet grating phase. The device comprises a multiple-quantum-well active region, and a complex-coupled grating formed by periodically etching grooves through a part of the active region. The semiconductor materials for a barrier layer where the groove etching is to be stopped, a regrown layer in the etched groove, and a laser cladding layer, are chosen all the same, so as to form an active grating entirely buried in the same material, providing a complex-coupling coefficient which is defined independently of the etching depth. The second feature, “facet power asymmetry”, is provided by composing the laser cavity of two sections (“front” and “back” sections) having different (“front” and “back”) Bragg wavelengths.