Method and device for delaying an electrical signal, the method and device being useable in various signal processing applications. A buried channel (41) is formed by disposing a portion of a layer of piezoelectric semiconductor material (40) between confining layers (50, 30). A surface acoustic wave is established in the piezoelectric semiconductor material via an input transducer (55). Majority carriers are depleted from the channel, and an electrical signal is injected into the channel via an interdigital transducer (55). A delayed version of the electrical signal, which had been carried along by the surface acoustic wave, can then be extracted from the channel via an output diode (71).

Acoustic charge transport device and method.

A thin web supported by a peripheral frame is formed from a single crystal of silicon, the web and frame being of opposite conductivity types. A lower resistivity region is diffused into the web, and the web is covered by an insulating layer having holes through which conductors are deposited in contact with each end of the diffused region. The resulting transducer can be used as a thermocouple or strain gage. For use as a thermocouple, one of the junctions between the diffused region and a conductor is situated near the center portion of the web. The diffused region comprises one leg of the thermocouple, and one of the conductors functions as the other leg. The frame acts as a heat sink relative to the center portion of the web, making the junction near the center portion a hot junction and the junction near the frame a cold junction. For use as a diaphragm type strain gage the diffused region is made to transverse most of the web. The frame serves as a mounting base that is integral with the strain gage. The resistance of the diffused region changes in proportion to the change of the dimensions of the diffused region that result from the application of a force normal to the plane of the web.

Transducer formed in peripherally supported thin semiconductor web

A hermetically sealed injection semiconductor laser device includes a hollow cylinder in which a crystal laser pellet is enclosed. The ends of the cylinder are sealed by metal electrodes one of which projects axially into the cylinder and is connected to an electrode surface of the crystal pellet. A lens element is disposed within the cylinder.

Hermetically sealed injection semiconductor laser device

A tunable semiconductor laser has an active layer, an insulating film made of a piezoelectric material and formed on a portion of the active layer, and an interdigital transducer provided on the insulating film for generating a surface acoustic wave. The laser oscillation wavelength is variable by varying the wavelength of the surface acoustic wave generated by the transducer. When adapted to produce surface acoustic waves of different frequencies at different locations, the transducer affords an enlarged tunable wavelength band. A plurality of Gunn diodes effecting oscillation at different frequencies are usable in place of the transducer.

Tunable semiconductor laser

Monolithic acoustoelectric signal storage device and means for generating a surface acoustic wave on piezoelectric material and propagating the wave into a storage region of the device. An electric field applied across a storage structure in the storage region of the device interacts with the electric field associated with the surface acoustic wave to produce a holographic replica of the wave in a spatially varying distribution of charge trapped at a solid dielectric-dielectric interface. The stored waveform may then be read out at a later time or, in nonlinear signal processing applications, the electric field of a subsequently generated surface acoustic wave may be propagated into the storage region to interact with the trapped charge to produce an output signal.

Monolithic surface acoustic wave signal storage device

An amplifier for Rayleigh surface acoustic waves in which an additional control is provided. A region of variable conductivity is located in close proximity to the surface on which the acoustic wave travels. Examples of this region are an inversion layer whose conductivity is controlled by electrical bias, and a bulk region whose conductivity is controlled by a variable width depletion region. The electric field produced by moving charge carriers in the variable conductivity region interacts with the piezoelectric field produced by the acoustic wave to transfer energy to the acoustic wave, or extract energy from this wave.

Acoustic wave amplifier having a coupled semiconductor layer

An injection laser whose light output is spatially modulated by internal effects in the active region of the laser. An acoustic wave is launched into the laser and is existent only in a small area including the active region of the laser. In low acoustic frequency operation, the acoustic wave is steered over an angle theta to cause the laser light output to be steered through this angle. In high frequency operation, the frequency of the acoustic wave can be changed to steer the light output, or the acoustic wave can be steered to cause light deflection, as in the low frequency case. The acoustic wave causes phase modulation and loss modulation which results in scanning of the light output. The acoustic wave can be a surface acoustic wave, a Love wave, or a Stonley wave.

Internal modulation of injection lasers using acoustic waves

1,256,060. Light modulators. INTERNATIONAL BUSINESS MACHINES CORP. 1 July, 1970 [27 Oct., 1969], No. 31796/70. Heading H4F. [Also in Divisions G2 and H1] At least one resonator reflector of a 10A6 A CO 2 laser consists of a crystal or liquid acoustic cell 14, a transducer 18 energized by a microwave generator 22 being used to form a reflective acoustic wave column 15. A partially transmissive output cell is shown, the transducer being connected to one side of the cell and functioning in conjunction with a diagonal surface 20 so as not to obscure the output optical path. The degree of transmission may be varied by adjusting the microwave signal source.

Lean Eric G

Papers

Acoustic wave amplifier having a coupled semiconductor layer

Internal modulation of injection lasers using acoustic waves

Volume reflector for laser cavities