K. Shimomura

Analysis of semiconductor intersectional waveguide optical switch-modulator

Transmission and reflection characteristics and wavelength chirping of a guided mode in a semiconductor intersectional optical switch-modulator are analyzed by considering the electric field-induced refractive index variation along with the absorption loss variation. The refractive index and absorption ratio, alpha /sub p/, is shown to determine the performance of the switch-modulator. A transmission port is suitable for a modulation with a high extinction ratio, low insertion loss, and small wavelength chirping. The insertion loss at the reflection port depends heavily on alpha /sub p/. A low insertion loss and high extinction ratio intersectional optical switch is possible when - alpha /sub p/ is higher than 10, which can be realized with a quantum box structure. >

Operational wavelength range of GaInAs(P)-InP intersectional optical switches using field-induced electrooptic effect in low-dimensional quantum-well structures

Operational wavelength range for low insertion loss and high extinction ratio of GaInAs(P)-InP intersectional optical switches consisting of low-dimensional quantum-well structures, such as quantum-box, quantum-wire, and quantum-film structures, is theoretically analyzed. It is found that superior operation characteristics can be attained with the lower-dimensional quantum-well structure. For instance, an operational wavelength range of around 10 nm for an insertion loss less than 1 dB and an extinction ratio higher than 50 dB can be obtained with the device using a quantum-box structure. >

Switching operation in OMVPE grown GaInAs/InP MQW intersectional optical switch structures

An intersectional optical switch structure with an intersecting angle of 6 degrees was fabricated on an organometallic vapor-phase epitaxy (OMVPE) grown GaInAs/InP multiple quantum-well (MQW) layered wafer. Switching operation using field-induced refractive index variation was successfully demonstrated at the reverse bias voltage of 8 V for the 1.6 mu m wavelength region. Based on this switching, the field-induced refractive index variation in the QW was estimated as around 1%.<<ETX>>

A novel integrated-twin-guide (ITG) optical switch with a built-in TIR region

The authors propose a novel integrated-twin-guide (ITG) optical switch with a built-in TIR region to enlarge the spatial separation of output lights, which is suitable for a compact optical switching matrix array. A switching operation was observed in a GaInAsP/InP MQW ITG optical switch utilizing electric-field induced refractive index variation.<<ETX>>

Low-drive voltage intersectional waveguide optical switch using GaInAs/InP MQW structure

A low-drive voltage intersectional waveguide optical switch using 1.6 mu m GaInAs/InP MQW (multiple quantum well) structure, which was fabricated by only one-step epitaxial growth of MQW structure followed by a one-step pattern etching of the waveguide is demonstrated. Extinction ratio at the straight port of 9.9 dB and that at the reflection port of 4.4 dB were obtained at an applied voltage of -4 V.<<ETX>>

Observation of field-induced refractive index variation in quantum box structure

An electric-field-induced refractive index variation in a GaInAs/InP five-layered quantum box structure was observed for the first time. The wavelength dependence of the refractive index variation was measured to confirm the quantum box effect. The size of the GaInAs/InP quantum box was estimated to be (22-30 nm)/sup 2/ with the thickness of 7.5 nm. from the spectral property of the field-induced refractive index variation. The maximum value of the refractive index variation in the quantum box was evaluated to be 7% around 1.52 mu m wavelength at an applied electric field of 8*10/sup 4/ V/Cm.<<ETX>>

Electric-Field-Induced Refractive Index Change In Gainasp/Inp Mqw Structures

Large change in the field induced refractive index is achievable by the use of the MQW structures. The property of which can be advantageously utilized to realize high speed external modulators and switches. The GalnAsP/InP MQW structures was prepared by LPE method and the electric field induced absorption was measured. Reflection of light due to refractive index change as well as absorption coefficient change was observed for the first time. Intersectional optical switch based on this change was also fabricated.