• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.1
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• pp.122-130
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• 2015

This paper presents a 6 Gb/s 4-channel arrayed transimpedance amplifiers (TIA) with the gain control for 4-channel passive optical network in $0.13{\mu}m$ complementary metal oxide semiconductor (CMOS) technology. A regulated cascode input stage and inductive-series peaking are proposed in order to increase the bandwidth. Also, a variable gain control is implemented to provide flexibility to the overall system. The TIA has a maximum $98.1dB{\Omega}$ gain and an input current noise level of about 37.8 pA/Hz. The die area of the fabricated TIA is $1.9mm{\times}2.2mm$ for 4-channel. The power dissipation is 47.64 mW/1ch.

• Korean Journal of Optics and Photonics
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• v.11 no.5
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• pp.340-346
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• 2000

Traveling wave type semiconductor optical amplifiers integrated with spot-size-converter (SSC-TW-SOA) have been extensively studied for the improvement of coupling effiClency With single-mode fiber and fO! the cost reducClon 111 a packaging In tlIis paper the slructural dependence of the spot-slZe-converter on the effective facet reflectlvllY $R_{eff}$ was experimentally as well as thcoretienlly mvestlgated. It was shown that not only a sufficient mode-conversion in a sse region along the latersl and tran~verse directions but also an introductIOn of angled-facet were very essential in order to reduce $R_{eff}$ Very small ripple less than 0.1 dB in an amplified spontaneous emission spectrum was observed with the fabncated SSC-lW-SOA which consists of the wrndow length of $20\mu\textrm{m}$, facet angle of $7^{\circ}$, and antlrelleetioll-coated facet of ] % reflectivity.tivity.

• Proceedings of the Optical Society of Korea Conference
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• 2004.02a
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• pp.312-313
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• 2004

The optical gain saturation and noise figure characteristics of 1550nm traveling-wave semiconductor optical amplifiers are analyzed experimentally and theoretically. The result shows that there is an optimum active layer thickness for high saturation output power and low noise figure.

• Proceedings of the Optical Society of Korea Conference
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• 2008.02a
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• pp.293-294
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• 2008

Using bi-direction SOA based Extension system, FTTH can enhance PON system by increasing both the upstream and downstream link budget. This increased link budget can be used to extend the distance, increase the split ratio or both. The bi-direction SOA regenerates signals using all-optical amplification, and is therefore transparent to data rate or protocol. The bi-direction SOA supports legacy as well as future FTTx standards. This is based on SOA's proprietary technology platform for the manufacturing of advanced discrete photonics and photonic integrated circuits (PICs). Because the bi-direction SOA uses the same InP semiconductor technology used in virtually all telecom lasers, it is able to amplify signals at 1310 and 1490 nm, wavelengths not accessible with commercial fiber-amplifier (EDFA) technology. Due to the extremely fast response time of the InP semiconductor optical amplifiers inside, the SOA can accommodate both continuous (downstream) and bursty (upstream) traffic.

• Korean Journal of Optics and Photonics
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• v.14 no.5
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• pp.509-514
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• 2003

Mach-Zehnder interferometric wavelength converters with monolithically integrated semiconductor optical amplifiers (SOA's) have been fabricated and characteristics of wavelength conversion at 10 Gb/s have been investigated for wavelength span of 40 nm. The devices have been achieved by using a butt-joint combination of buried ridge structure type SOA's and passive waveguides. In the integration, a new method has been applied that removes p+InP cladding layer leading to high propagation loss and forms simultaneously the current blocking and the cladding layer using undoped InP. The module packaging has been achieved by using a titled fiber array for effective coupling into the tilted waveguide in the wavelength converter. Using the module, wavelength conversion with power penalty lower than 1 ㏈ at 10 Gb/s has been demonstrated for wavelength span of 40 nm. In addition, it is show that the module can provide 2R (re-amplification, re-shaping) operation by demonstrating the conversion with the negative penalty.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.1
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• pp.119-128
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• 1995

We report hybrid and passive mode-locking results of tilted-stripe AlGaAs semiconductor laser traveling wave amplifiers with saturable absorbers. Dependence ofthe pulse width on the mode locking frequency, the bandwidth of spectral filters, and the bias current of the laser amplifier are investigated. We generate 4 ps optical pulses by using the hybrid mode locking technique. The repetition rate and the peak power of generated pulses are 516 MHz and 170 mW, respectively. The tuning range of uor mode locked laser is 10 nm with the center wavelength of 780 nm. We also generate 2.6 ps optical pulses with peak power of 830 mW by using the passive mode locking technique.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.135-135
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• 2004

• Current Optics and Photonics
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• v.2 no.6
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• pp.519-524
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• 2018

We propose a transverse load sensor with reconfigurable measurement accuracy based on a microwave photonic filter in the $K_u$ band, incorporating a polarization-maintaining fiber Bragg grating. A prototype sensor with a reconfigurable measurement accuracy tuning range from 6.09 to 9.56 GHz/(N/mm), and corresponding minimal detectable load range from 0.0167 to 0.0263 N/mm, is experimentally demonstrated. The results illustrate that up to 40% manufacturing error in the grating length can be dynamically calibrated to the same corresponding measurement accuracy for the proposed transverse load sensor, by controlling the semiconductor optical amplifier's injection current in the range of 154 to 419 mA.

• Korean Journal of Optics and Photonics
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• v.19 no.3
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• pp.237-241
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• 2008

An all-optical encryption system built on the basis of electrical logic circuit design principles is proposed, using semiconductor optical amplifier (SOA) exclusive or (XOR) logic gates. Numerical techniques (steady-state and dynamic) were employed in a sequential manner to optimize the system parameters, speeding up the overall design process. The results from both numerical and experimental testbeds show that the encoding/decoding of the optical signal can be achieved at a 10 Gbps data rate with a conventional SOA cascade without serious degradation in the data quality.

• Korean Journal of Optics and Photonics
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• v.23 no.4
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• pp.143-146
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• 2012

All-optical data extraction, one of the key technologies for all-optical computing and optical communication to perform add-drop, packet switching, and data reset, etc., is experimentally demonstrated by using cross-gain modulation (XGM) of semiconductor optical amplifiers (SOAs). Also, all-optical data extraction based on numerical simulation is performed by using the VPI simulation tool. In this paper, the suggested optical system based on SOAs shows the potential for high speed, and highly integrable and low power optical data computing.