• Journal of the Microelectronics and Packaging Society
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• v.27 no.4
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• pp.47-54
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• 2020

Integration of active and passive waveguides is an essential component of the photonic integrated circuit and its elements. Butt joint is one of the important technologies to accomplish it with significant advantages. However, it suffers from high optical loss at the butt joint junction and need of accurate process control to align both waveguides. In this study, we used beam propagation method to simulate an integrated device composed of a laser diode and spot size converter (SSC). Two SSCs with different mode properties were combined with laser waveguide and optical coupling efficiency was simulated. The SSC with larger near field mode showed lower coupling efficiency, however its far field pattern was narrower and more symmetric. Tapered passive waveguide was utilized for enhancing the coupling efficiency and tolerance of waveguide offset at the butt joint without degrading the far field pattern. With this technique, high optical coupling efficiency of 89.6% with narrow far field divergence angle of 16°×16° was obtained.

• 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.

• Korean Journal of Optics and Photonics
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• v.11 no.3
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• pp.179-186
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• 2000

Optical coupling coefficients and misalignment tolerance of 155 Mbps optical transmitter module of passive alignment technology, to be usable in ATM system, B-NT (Broadband Network Termination) system, and 10 G transmission system for information super-highway networks, were calculated, compaired with it's engineer samples, and discussed. These engineer samples of -4.5 dBm maximum output power were packaged in the method of butt coupling of flat-fiber and tested reliability evaluation. Hence the cheap packaging method of optical transmitter module was researched. rched.

• Korean Journal of Optics and Photonics
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• v.14 no.3
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• pp.327-330
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• 2003

We present the fabrication and measured performance of a wavelength tunable Butt coupled DBR-LD. An average coupling efficiency between active layer and passive waveguide layer was measured over 85％per facet, and the average threshold current was 21 ㎃ for the waveguide integrated DBR laser. High output power of Butt coupled DBR-LD was obtained over 25 ㎽. As high as 25 ㎽ of output power was achieved by the butt coupled method. The maximum wavelength tuning range is about 7.4 nm, and the side mode suppression ratio was more than 40 ㏈ using 1.3 ${\mu}{\textrm}{m}$ InGaAsP waveguide layer.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.9
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• pp.666-672
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• 2003

In this paper, we described the fabrication and the performance of wavelength tunable distributed bragg reflector (DBR) laser diode (LD), having different waveguide coupling mechanisms; integrated-twin-guide (ITG) DBR-LD and butt coupled (BT) DBR-LD. This deviceis fabricated by metal organic vapor phase epitaxy (MOVPE) growth and planar buried heterostructure (PBH)-type transverse current confinement structure. The result of measurement, the optical performance of BT-DBR-LD is better over 2 times than that of ITG-DBR-LD at the variation of threshold current and output power, and slop efficiency due to the higher coupling efficiency of the butt coupled structure than the integrated twin guide structure. The maximum wavelength tuning range is about 7.2nm for ITG DBR-LD and 7.4nm for BT DBR-LD. Both types of lasers have a very high yield of single mode operation with a side-mode suppression ratio of more than 35dB.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.5
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• pp.400-406
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• 1998

We investigated the preparation and guided-mode properties of $Ti:LiNbO_3$ waveguides which were fabricated by Ti in-diffusion. The diffusion method to reduce the Li out-diffusion was proposed. The optical guided-mode and propagation loss based on butt-coupling pigtailed with PMF-input were measured. How to improve the polishing grade of waveguide endfaces is newly proposed in this paper. To show the mode propagations, the BPM simulations of channel waveguide are described.

• 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 Telematics and Electronics D
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• v.34D no.1
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• pp.49-54
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• 1997

We proved the feasibiltiy of a parallel optical interconnection technique using single GRIN (graded-index) rod lens as an intermediate coupling device, which increases the working distance and makes packaging easy. The proposed technique shows relatively less dependency on misalignments. In this paper, for convensience of experiments, we applied this method to 4-channel coupling between two fiber arrays, and compared it with butt-coupling and the method of using ball lens. The comparison shows the feasibility of adopting the proposed method to the parallel interconnection between a laser diode array and an optical fiber array.

• 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.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.11
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• pp.160-165
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• 2016

The rapidly developing applications of optical fiber in sensors, sensor system and super high speed optical communication have begun to produce tangible demands for optical coupler and connected WDM. we have designed and made Hopper type WDM (national patent NO:10-1502954). The Hopper type WDM is bi-directional $1{\times}3$ WDM of asymmetry Butt coupling for super high speed optical communication. The Hopper type WDM is used central wavelength of each 850nm,1300nm,1550nm. The Hopper type WDM has an excellent merits which the existing WDM and also it has an excellent signal of super high speed and economic in made. The characteristic of Hopper type WDM is superior in ave 0.02-0.03dB as compared with $1{\times}3$ optical coupler to excess loss. Especially, we can expect the utilization of super high speed optical MUX and also can be developed as the high-sensibility signal detected system in using optical sensor system parts.