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 Development
of high-performance / functional quantum-effect photonic devices and
fundamental technologies for future light wave communication systems.
Arai Lab
http://www.pe.titech.ac.jp/AraiLab/index-e.html
Objective
The purpose of this study is to develop high-performance / functional
quantum-effect photonic devices for future light wave communications,
and extremely low-damage processing of ultra-fine structures as well
as technologies for integration of functional photonic devices.
Research Field
Optical and quantum electronics, Optoelectronics, Light wave communications,
Semiconductor photonic devices
Research Theme
1. Ultra-low-damage fabrication technologies for ultra-fine structures
We are developing ultra-low-damage fabrication technologies of ultra-fine
structures for high-performance photonic devices utilizing the quantum-size
effect. As a candidate the combination of a direct patterning by an
electron-beam-exposure (EBX) and a reactive-ion-etching (RIE) with
CH4/H2 gas mixture followed by an embedding growth by an organo-metallic
vapor-phase-epitaxy (OMVPE) has been employed to realize fine GaInAsP/InP
5-layered quantum-wire (width: 23nm, period: 80nm) lasers (Fig. 1).
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| Fig 1: Cross sectional
SEM image of 4-layered quantum-wire laser. |
2. Long wavelength semiconductor lasers for future light wave communications
Taking an advantage of the low-damage fabrication process, a record
low threshold current (0.7mA) as well as a record low threshold current
density (94A/cm2) of 1.55mm GaInAsP/InP distributed feedback (DFB)
lasers was achieved by using wire like active regions. No degradations
after 1-year RT-CW aging test were observed (Fig. 2).
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| Fig 2: Cross sectional
SEM image and L-I characteristics of DFB lasers with wire like
active regions. |
Membrane BH-DFB lasers consisting of wire like active regions buried
in 140nm thick semiconductor were fabricated. A low threshold RT-CW
operation with a stable single-mode property under optical pumping
(1.5mW: corresponding threshold current 27mA) was achieved (Fig. 3).
Low threshold current (2.8mA) operation of distributed reflector (DR)
lasers consisting of vertical grating (VG) DFB and DBR regions were
realized (Fig. 4). We are aiming at a breakthrough in processing technologies
to realize high-performance/functional photonic devices as well as
to propose novel photonic devices based on quantum-effects.
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| Fig 3:
Cross sectional SEM image and L-I characteristics of DFB lasers
with wire like active regions. |
Fig. 4
: Structure and L-I characteristics of a DR laser with vertical-grating
DFB and DBR regions. |
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