Process gas discharged from a bypass pipe to a gas exhaust system can be prevented from diffusing back to the inside of a process chamber without having to install a dedicated vacuum pump at the downstream side of the bypass pipe. The substrate processing apparatus includes a process chamber accommodating a substrate, a gas supply system supplying process gas from a process gas source to the process chamber for processing the substrate, a gas exhaust system configured to exhaust the process chamber, two or more vacuum pumps installed in series at the gas exhaust system, and a bypass pipe connected between the gas supply system and the gas exhaust system. The most upstream one of the vacuum pumps is a mechanical booster pump, and the bypass pipe is connected between the mechanical booster pump and the rest vacuum pumps located at a downstream side of the mechanical booster pump.

Substrate Processing Apparatus

Tunable semiconductor lasers have been listed in numerous critical technology lists for future optical communication and sensing systems. This paper summarizes a tutorial that was given at OFC '03. It includes some discussion of why tunable lasers might be beneficial, an outline of basic tuning mechanisms, some examples of tunable lasers that have been commercialized, and a discussion of control techniques. More extensive data is given for the widely-tunable sampled-grating distributed-Bragg-reflector (SGDBR) type of laser, including data for such lasers integrated monolithically with modulators to form complete transmitter front ends. A summary of reliability data for the SGDBR laser is also given. It is concluded that tunable lasers can reduce operational costs, that full-band tunability is desirable for many applications, that monolithic integration offers the most potential for reducing size, weight, power and cost, and that sufficient reliability for system insertion has been demonstrated.

/pdf/tunable-semiconductor-lasers-a-tutorial-u60opvuxtv.pdf

Tunable semiconductor lasers: a tutorial

After over two decades of exploration, tunable diode lasers are beginning to find significant applications, driven largely by the huge demand for bandwidth that is guiding many developments in the optical fiber communication business today. In the paper, some of the history and key developments that have led to the technologies available today are reviewed from the perspective of the author. After discussion of some of the early work, the focus shifts to widely tunable diode lasers, which would appear to be key enablers for future dense wavelength-division multiplexing and optical switching and networking systems. The distinguishing characteristics of the current technological alternatives are summarized.

Monolithic tunable diode lasers

A Group III nitride based semiconductor device is disclosed, comprising: a doped Group III nitride layer; and a gallium nitride based superlattice directly on the doped Group III nitride layer, the gallium nitride superlattice being doped with an n-type impurity and having at least two periods of alternating layers of InXGa1-XN and InYGa1-YN, where 0 ≤ X < 1 and X is not equal to Y and wherein a thickness of a first of the alternating layers is less than a thickness of a second of the alternating layers.

Group III nitride based light emitting diode structures with a quantum well and superlattice, group III nitride based quantum well structures and group III nitride based superlattice structures

Opto-electrical systems having electrical and optical interconnections formed in thin layers with thin-film active devices are disclosed. In one embodiment, optical connections are made between the edge of one substrate and the surface of another substrate with the use of photorefractive materials. In another embodiment, the optical connection is made by separating a optical film from the first substrate and coupling the first substrate and the optical film to separate receptacles located on the second substrate. Film optical link modules employing aspects of the invention are also disclosed.

Systems based on opto-electronic substrates with electrical and optical interconnections and methods for making

A light wavelength filtering circuit in a wavelength-division multiplexing light communication system minimizes transmission loss in the waveguide after wavelength discrimination by having a linear output waveguide added to an output end of a light wavelength discriminating element, at which a signal having a long wavelength is outputted. A curved output waveguide is added to the rear stage of the output end at which a signal having a relatively short wavelength is outputted. Hence, a radiation loss at the output waveguide at the output end is minimized, while a space between the output light waveguides is being widened. Additionally, a core layer bandgap wavelength at the output waveguide of the long wavelength signal is set to be longer than a core layer band gap wavelength in another region. Hence, a substantial light confinement is formed in a horizontal direction even in the output waveguide at the long wavelength signal side and even if the output waveguide at the long wavelength signal side is curved, and the radiation loss can be reduced.

Light wavelength filtering circuit and manufacturing method thereof

PROBLEM TO BE SOLVED: To improve reliability of displaying virtual images of vehicle related information.SOLUTION: A stepping motor 40, which rotates a reflector 32 to adjust a display position of a virtual image 36 when energized by a drive signal applied thereto, has an electrical stability point θe, where the motor is electrically stable due to a holding torque while being energized, and a mechanical stability point θm where the motor is mechanically stable due to a detent torque when not being energized. A control system 70 controls the drive signal fed to the stepping motor 40 in accordance with externally entered adjustment commands. Such a configuration allows the stepping motor 40 to work in an energized rotation mode Me, where the control system 70 continues to feed the drive signal when the adjustment command input has stopped until the electrical stability point θe is reached and, upon reaching the electrical stability point θe, the control system 70 stops feeding the drive signal to the stepping motor 40, and then in a momentum rotation mode Mm where the stepping motor 40 inertially rotates toward the mechanical stability point θm.

Vehicle-mounted head-up display

Growth pressure dependence of neighboring mask interference in densely arrayed narrow-stripe selective MOVPE for integrated photonic devices

We developed compact (1.136 mm ) eight-channel wavelength-selectable microarray distributed feedback laser diodes (DFB-LD's) with a monolithically integrated mul- timode-interference (MMI) optical combiner, a semiconductor optical amplifier (SOA), and an electro-absorption (EA) modu- lator. By using C thermal tuning, an addressable wavelength range of 15.3 nm with uniform device characteristics and 2.5-Gb/s modulation performance were successfully demonstrated. Index Terms—Distributed-feedback (DFB) laser, microarray, modulator, multimode-interference (MMI), selective MOVPE, semiconductor optical amplifier (SOA), wavelength division multiplexing (WDM), wavelength-selectable light source.

1.55- m Wavelength-Selectable Microarray DFB-LD's with Monolithically Integrated MMI Combiner, SOA, and EA-Modulator

Here we propose novel active multi-mode-interferometer (MMI) laser diodes (LDs) for 14XXnm fiber amplifier pump applications. The waveguide of the LDs is consisted from 1x1-MMI couplers integrated with 1st order-mode permitted waveguides to enhance the total active area. Although there is no single-mode waveguide region inside the cavity, the novel active MMI-LDs emitted in stable single-transverse-mode output up to maximum output power. Moreover, they achieved high output power of 1.46W, and low driving voltage of only 1.75V at 1W output power.

Tatsuya Sasaki

Papers

Light wavelength filtering circuit and manufacturing method thereof

Vehicle-mounted head-up display

Growth pressure dependence of neighboring mask interference in densely arrayed narrow-stripe selective MOVPE for integrated photonic devices

1.55- m Wavelength-Selectable Microarray DFB-LD's with Monolithically Integrated MMI Combiner, SOA, and EA-Modulator

First demonstration of novel active multi-mode interferometer (MMI) LDs integrated with 1st order-mode permitted waveguides