INVESTIGATION OF MATERIAL GAIN OF In0.90Ga0.10As0.59P0.41/InP LASING NANO-HETEROSTRUCTURE

2014 ◽  
Vol 28 (10) ◽  
pp. 1450068 ◽  
Author(s):  
RASHMI YADAV ◽  
PYARE LAL ◽  
F. RAHMAN ◽  
S. DALELA ◽  
P. A. ALVI
Keyword(s):  
Refractive Index ◽  
Communication Systems ◽  
Refractive Index Change ◽  
Single Quantum Well ◽  
Lasing Wavelength ◽  
Index Change ◽  
Te Mode ◽  
Tm Mode ◽  
Material Gain ◽  
Valence Bands

In this paper, we have proposed a step separate confinement heterostructure (SCH) based lasing nano-heterostructure In 0.90 Ga 0.10 As 0.59 P 0.41/ InP consisting of single quantum well (SQW) and investigated material gain theoretically within TE and TM polarization modes. In addition, the quasi Fermi levels in the conduction and valence bands along with other lasing characteristics like anti-guiding factor, refractive index change with carrier density and differential gain have also been investigated and reported. Moreover, the behavior of quasi Fermi levels in respective bands has also been correlated with the material gain. Strain dependent study on material gain and refractive index change has also been reported. Interestingly, strain has been reported to play a very important role in shifting the lasing wavelength of TE mode to TM mode. The results investigated in the work suggest that the proposed unstrained nano-heterostructure is very suitable as a source for optical fiber based communication systems due to its lasing wavelengths achieved at ~1.35 μm within TM mode, while ~1.40 μm within TE mode.

scholarly journals All-optical switching using a new photonic crystal directional coupler

2015 ◽  
Vol 4 (1) ◽  
pp. 63 ◽  
Author(s):  
B. Vakili ◽  
S. Bahadori-Haghighi ◽  
R. Ghayour
Keyword(s):  
Refractive Index ◽  
Photonic Crystal ◽  
Communication Systems ◽  
Optical Switching ◽  
Directional Coupler ◽  
Refractive Index Change ◽  
Control Signal ◽  
Index Change ◽  
All Optical ◽  
All Optical Switching

In this paper all-optical switching in a new photonic crystal directional coupler is performed.  The structure of the switch consists of a directional coupler and a separate path for a control signal called “control waveguide”. In contrast to the former reported structures in which the directional couplers are made by removing a row of rods entirely, the directional coupler in our optical switch is constructed by two reduced-radius line-defect waveguides separated by the control waveguide. Furthermore, in our case the background material has the nonlinear Kerr property. Therefore, in the structure of this work, no frequency overlap occurs between the control waveguide mode and the directional coupler modes. It is shown that such a condition provides a very good isolation between the control and the probe signals at the output ports. In the control waveguide, nonlinear Kerr effect causes the required refractive index change by the presence of a high power control (pump) signal. Even and odd modes of the coupler are investigated by applying the distribution of the refractive index change in the nonlinear region of a super-cell so that a switching length of about 94 µm is obtained at the wavelength of 1.55 µm. Finally, all-optical switching of the 1.55 µm probe signal using a control signal at the wavelength of 1.3 µm, is simulated through the finite-difference time-domain method, where both signals are desirable in optical communication systems. A very high extinction ratio of 67 dB is achieved and the temporal characteristics of the switch are demonstrated.

Robust Exciton Polariton in a Quantum-Well Waveguide

1998 ◽  
Vol 536 ◽  
Author(s):  
M. Shirai ◽  
K. Hosomi ◽  
T. Mishima ◽  
T. Katsuyama
Keyword(s):  
Refractive Index ◽  
Quantum Well ◽  
Temperature Dependence ◽  
Light Propagation ◽  
Directional Coupler ◽  
Refractive Index Change ◽  
Driving Voltage ◽  
Single Quantum Well ◽  
Index Change ◽  
Switching Devices

AbstractThe refractive index change of polariton propagation in a GaAs quantum-well waveguide was measured as a function of the electric field. Its temperature dependence was also measured. The experimental results showed that the refractive index change of the polariton propagation was at least three times as large as that of the conventional light propagation. This effect remains up to 40 K, and coincides with the temperature dependence of the rate of polariton scattering by phonons. We also Fabricated directional-coupler-type switching devices to apply this large refractive index change, and were able to demonstrate the operation in a single quantum-well waveguide. Our results indicate that extremely small and low driving voltage switching devices may be feasible.

scholarly journals Biaxial Strain Effects on Optical Characteristics of Quantum Well Lasers

2001 ◽  
Vol 23 (4) ◽  
pp. 237-253 ◽  
Author(s):  
J. S. Hsu ◽  
Ming Rong Lee ◽  
K. F. Yarn
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Quantum Well ◽  
Tensile Strain ◽  
Refractive Index Change ◽  
Quantum Well Lasers ◽  
Biaxial Strain ◽  
Index Change ◽  
Tm Mode ◽  
Peak Gain

The effects of biaxial strain produced by the lattice mismatch of constituent materials on the optical properties of strainedIn1−xGaxAsyP1−y/In1−xGaxAsquantum well lasers are investigated.The optical gain and refractive index change of a biaxially stressed quantum well lasers are studied theoretically using the multiband effective mass equation (i.e.,k→⋅p→method), deformation potential theory and Fermi-Golden rule, band mixing effect is retained in the calculations. It is found that the biaxial strain would change the subband structures and optical properties of quantum well lasers, we found the gain of TE mode increases with increasing compressive strain, while the gain of TM mode increases with increasing tensile strain, these will be benefited for reducing the threshold current depending on whether the quantum well lasers are operating in TE or TM mode. On the other hand, the refractive index change in the active region near the TE(TM) mode peak gain becomes more negative when a biaxial compressive(tensile) strain is applied, it leads to the conclusion that the strain weakens the optical confinement, the temperature dependence of gain also becomes stronger when there is strain.Finally, we also found the minimum peak gain occurs when a small tensile strain is applied, but no strain.

scholarly journals Critical angle reflection imaging for quantification of molecular interactions on glass surface

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Guangzhong Ma ◽  
Runli Liang ◽  
Zijian Wan ◽  
Shaopeng Wang
Keyword(s):  
Refractive Index ◽  
Small Molecule ◽  
Molecular Interactions ◽  
Glass Surface ◽  
Critical Angle ◽  
Dynamic Range ◽  
Refractive Index Change ◽  
Label Free ◽  
Index Change ◽  
Sensing Range

AbstractQuantification of molecular interactions on a surface is typically achieved via label-free techniques such as surface plasmon resonance (SPR). The sensitivity of SPR originates from the characteristic that the SPR angle is sensitive to the surface refractive index change. Analogously, in another interfacial optical phenomenon, total internal reflection, the critical angle is also refractive index dependent. Therefore, surface refractive index change can also be quantified by measuring the reflectivity near the critical angle. Based on this concept, we develop a method called critical angle reflection (CAR) imaging to quantify molecular interactions on glass surface. CAR imaging can be performed on SPR imaging setups. Through a side-by-side comparison, we show that CAR is capable of most molecular interaction measurements that SPR performs, including proteins, nucleic acids and cell-based detections. In addition, we show that CAR can detect small molecule bindings and intracellular signals beyond SPR sensing range. CAR exhibits several distinct characteristics, including tunable sensitivity and dynamic range, deeper vertical sensing range, fluorescence compatibility, broader wavelength and polarization of light selection, and glass surface chemistry. We anticipate CAR can expand SPR′s capability in small molecule detection, whole cell-based detection, simultaneous fluorescence imaging, and broader conjugation chemistry.

InP-based optical switch module operating through carrier-induced refractive index change

1990 ◽  
Vol 29 (3) ◽  
pp. 191 ◽  
Author(s):  
Takeshi Kato ◽  
Hiroaki Inoue ◽  
Yasushi Takahashi ◽  
Koji K. Ishida
Keyword(s):  
Refractive Index ◽  
Optical Switch ◽  
Refractive Index Change ◽  
Index Change ◽  
Switch Module
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