• Journal of Integrative Natural Science
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• v.7 no.1
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• pp.1-4
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• 2014

Distributed Bragg reflector porous silicon of different characteristics were formed to determine their optical constants in the visible wavelength range using a periodic square wave current between low and high current densities. The surface and cross-sectional SEM images of distributed Bragg reflector porous silicon were obtained using a cold field emission scanning electron microscope. The surface image of distributed Bragg reflector porous silicon indicates that the distributions of pores are even. The cross-sectional image illustrates that the multilayer of distributed Bragg reflector porous silicon exhibits a depth of few microns and applying of square current density during the etching process results two distinct refractive indices in the contrast. Distributed Bragg reflector porous silicon exhibited a porosity depth profile that related directly to the current-time profile used in etch. Its free-standing film was obtained by applying an electro-polishing current.

• Journal of Integrative Natural Science
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• v.3 no.1
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• pp.33-37
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• 2010

The functionalized photonic crystals of porous silicon biosensor was prepared for the application as a label-free biosensor based on distributed Bragg reflector interferometer. Prepared distributed Bragg reflector of porous silicon biosensor displayed sharp reflection in the optical reflective spectra. The mean of construction of molecular architectures on distributed Bragg reflector of porous silicon surfaces was investigated for the step-by-step binding interaction with amines, biotin, avidin, and biotinylated protein A. The subsequent introduction of avidin, and biotinylated protein A resulted in the reflectivity shifted to longer wavelengths, indicative of a change in refractive indices induced by binding of biomolecules.

• Journal of Integrative Natural Science
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• v.4 no.3
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• pp.192-196
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• 2011

New method to encode multiple photonic features of Bragg type reflector on silicon wafer has been investigated. Multiple bit encodes of distributed Bragg reflector features have been prepared by electrochemical etching of crystalline silicon by using various square wave current densities. Optical characterization of multi-encoding of distributed Bragg reflectors on porous silicon was achieved by Ocean optics 2000 spectrometer for the search of possible applications of multiple bit encoding of distributed Bragg reflectors such as multiplexed assays and chemical sensors. The morphology and cross-sectional structure of multi-encoded distributed Bragg reflectors was investigated by field emission scanning electron micrograph.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.2
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• pp.241-246
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• 2021

In this paper, hydrogenated amorphous silicon(a-Si:H) grating coupler with distributed Bragg reflector(DBR) is proposed to achieve high-efficiency nanophotonic radiator for Light Detection and Ranging(LiDAR) application. The DBR reduces downward leakage of the optical field below the grating region. As a result, the far-field intensity shows about 1.4 times stronger, compared to the common grating coupler without the DBR.

• Korean Journal of Optics and Photonics
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• v.28 no.5
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• pp.229-235
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• 2017

A widely tunable U-shaped SGDBR (Sampled Grating Distributed Bragg Reflector) laser diode is designed and analyzed by means of a time-domain simulation. The U-shaped SGDBR laser diode consists of SGDBR, active, phase, and TIR (Total Internal Reflection) mirror sections, so the coupling losses across the sections should be carefully considered. The tuning range of the designed U-shaped SGDBR laser is about 1525-1570 nm, which is confirmed by the simulation. The simulation results show that the loss in the TIR mirror region should be less than about 2 dB, and the refractive-index difference at the butt coupling between the passive and active regions should be less than 0.1, to provide the complete tuning range.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.1
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• pp.16-20
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• 2004

We present the fabrication and performance of wavelength tunable butt coupled (BT) sampled-grating (SG) distributed bragg reflector (DBR) - planar buried heterostructure (PBH) laser diodes (LD). The fabricated LD showed the high optical output power due to the high coupling efficiency between active and passive components by the BT coupling methods. The series resistance and diode ideality factor of LD were measured to be 3.7 $\Omega$ and 1.35, respectively. The average threshold current was 25 ㎃. The output powers of BT-SG DBR-PBH-LD were obtained to be as high as 12.3 and 24.56 ㎽ at 100 and 200 ㎃, respectively. The maximum wavelength tuning range was about 31 nm and the side mode suppression ratio was about 37 dB.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.19 no.6
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• pp.293-297
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• 2009

In this paper, we made three kinds of porous silicon samples (single layer, distributed Bragg reflector, and microcavity) by electrochemical etching p-type silicon substrate. And then, we investigated their reflectance spectrum properties. We found that the number of fringe patterns and the maximum reflectivity of porous silicon multilayer increased compared with a porous silicon sinlge layer. In addition, we can observe that the DBR (distributed Bragg reflector) porous silicon has a full-width at half-maximum about 33 nm which is narrower than the porous silicon single layer and porous silicon microcavity.

• ETRI Journal
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• v.45 no.1
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• pp.163-170
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• 2023

We report an electroabsorption modulator (EAM)-integrated distributed Bragg reflector laser diode (DBR-LD) capable of supporting a high data rate and a wide wavelength tuning. The DBR-LD contains two tuning elements, plasma and heater tunings, both of which are implemented in the DBR section, which have blue-shift and red-shift in the Bragg wavelength through a current injection, respectively. The light created from the DBR-LD is intensity-modulated through the EAM voltage, which is integrated monolithically with the DBRLD using a butt-joint coupling method. The fabricated chip shows a threshold current of approximately 8 mA, tuning range of greater than 30 nm, and static extinction ratio of higher than 20 dB while maintaining a side mode suppression ratio of greater than 40 dB under a window of 1550 nm. To evaluate its modulation properties, the chip was bonded onto a mount including a radiofrequency line and a load resistor showing clear eye openings at data rates of 25 Gb/s nonreturn-to-zero and 50 Gb/s pulse amplitude modulation 4-level, respectively.

• Journal of Integrative Natural Science
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• v.5 no.1
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• pp.27-31
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• 2012

Relationship between reflection resonance and applied current density in Bragg photonic crystal has been investigated. Multiple bit encodes of distributed Bragg reflector features have been prepared by electrochemical etching of crystalline silicon by using various square wave current densities. Optical characterization of multi-encoding of distributed Bragg reflectors on porous silicon was achieved by Ocean optics 2000 spectrometer for the search of possible applications of multiple bit encoding of distributed Bragg reflectors such as multiplexed assays and chemical sensors. The morphology and cross-sectional structure of multi-encoded distributed Bragg reflectors was investigated by field emission scanning electron micrograph.

• Korean Journal of Optics and Photonics
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• v.15 no.5
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• pp.469-474
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• 2004

We have fabricated and designed wavelength-tunable sampled grating distributed Bragg reflector laser diodes(SGDBR-LD) by using, for the first time, planar buried heterostructures(PBH). The diodes have low threshold current values and high-performance of laser operation. Growth condition using metal organic chemical vapor deposition(MOCVD) was optimized for the formation of a good butt-coupling at the interface. A maximum output power of the fabricated device was 20 mW under 200 mA continuous wave(CW) operation at $25^{\circ}C$. Average threshold current and voltage were 12 mA and 0.8 V, approximately. This output power is higher than those of ridge waveguide(RWG) and buried ridge stripe(BRS) structures by amounts of 9 mW and 13 mW, respectively. We obtained a tuning range of 44.4nm which is well matched with the target value of our design. The side mode suppression ratio of more than 35 dB was obtained for the whole tuning range. Optical output power variation was less than 5 dB, which is 4 dB smaller than that of RWG structures.