• Journal of the Korean Institute of Telematics and Electronics A
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• v.28A no.10
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• pp.806-813
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• 1991

In this paper, we suggested the diagnosis of the optical FSK transmitter output characteristics using the Micheloson interferometer. The transmitter is designed by the direct frequency modulation effect of a semoconductor laser diode. The optical FSK transmitter consists of a temperature stabilized semiconductor laser diode and an optimally designed equalizer. It is modulated by 100Mbit/s PRBS Generator to diagonosis of Optical FSK transmitter output characteristics. The Michelson Interferometer is used for the optical frequency discriminator which transforms the output frequency of the transmitter to the amplitude of light. The measurement of the performance of the transmitter to the amplitude of light. The measurement of the performance of the transmitter computer the transmitted data and their eye pattern with the simulation results, the received data and their eye pattern. As the result of experiment, the data transfer rate of the transmitters is 100Mbit/s.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.4
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• pp.612-619
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• 1990

In this paper, a design method of optical FSK transmitter is described using LD-FM circuit model. In the design of optical FSK transmitter, an optimum bias current was chosen using LD-FM circuit model, and an unequalized FM transfer function was determined at this current. The equalizers that can make this transfer function uniform were designed by use of a simple passive network. For the designed optical FSK transmitter, the pulse-transient and small-signal frequency-deviation responses were simulated and discussed.

• Proceedings of the Optical Society of Korea Conference
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• 1997.08a
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• pp.111-113
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• 1997

The purpose of this paper is to propose a production flow for 155Mbps transmitter/receiver optical modules. Compact optical module packages for use as 155Mbps optical interfaces are developed by implementing a self-alignment principle for the formation of V-grooves and solder bumps. on the bases of experimental results of two hundreds of receiver/transmitter optical modules, each steps and flows of our production are developed by production efficiencies.

• Korean Journal of Optics and Photonics
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• v.15 no.4
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• pp.349-354
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• 2004

As a transmitter sub-assembly in the XFP(10 Gb/s Small Form Factor Pluggable) transceiver module, a transmitter optical sub-assembly(TOSA) is designed, fabricated and characterized in view of electrical and thermal performances. For a low-cost and compact packaging TOSA, the bias-tee and the matching resistor are monolithically integrated on the AlN sub-mount and a newly designed coplanar waveguide is drawn in the TO-stem. All optoelectronic components packaged in the TOSA are modeled by the equivalent circuit, which helps to improve and characterize the TOSA performance. The fabricated TOSA shows the -3㏈ bandwidth as high as 11 GHz at an elevated temperature of 85$^{\circ}C$.

• Proceedings of the Optical Society of Korea Conference
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• 2006.02a
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• pp.373-374
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• 2006

This paper physically demonstrates that our proposed method improves the Signal-to-Noise Ratio (SNR) of significantly increase the number of acceptable optical signals in PON(Passive Optical Network) systems. This method reduced Optical Beat Interference(OBI) by using CDMA.

• Journal of the Optical Society of Korea
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• v.13 no.4
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• pp.434-438
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• 2009

In this paper, a 12.5-Gb/s optical transmitter is implemented using 0.13-${\mu}m$ CMOS technology. The optical transmitter that we constructed compensates temperature effects of VCSEL (Vertical cavity surface emitting laser) using auto-power control (APC) and auto-modulation control (AMC). An external monitoring photodiode (MPD) detects optical power and modulation. The proposed APC and AMC demonstrate 5$\sim$20-mA of bias-current control and 5$\sim$20-mA of modulation-current control, respectively. To enhance the bandwidth of the optical transmitter, an active feedback amplifier with negative capacitance compensation is exploited. The whole chip consumes only 140.4-mW of DC power at a single 1.8-V supply under the maximum modulation and bias currents, and occupies the area of 1280-${\mu}m$ by 330-${\mu}m$ excluding bonding pads.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.12
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• pp.16-22
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• 1994

In this paper, transmitter and receiver modules for free space optical interconnection are implemented and characterized. In the transmitter module, bias circuitry which inject current into the direct modulated laser diode is fabricated and in the receiver module, p-i-n diode is integrated with an MMIC amplifying stage. Laser diode has a direct-modulated bandwidth of 2 GHz at 1.4 Ith bias while p-i-n diode and amplifying stage has a bandwidth of 1.3 GHz and 1.5 GHz, repectively. Optical interconnection has a bandwidth of 1.3 GHz and linearly transmit modulated voltage signal up to 1.5 Vp-p. Measured loss of optical interconnection is 5dB which is composed of optoelectronic conversion loss of 15 dB, electrical impedance mismatch loss of 6.7 dB in transmitter module and gain of 18 dB in receiver module. Seperation between transmitter and receiver can be extended up to 50 cm by using a lens.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.909-912
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• 1999

This paper describes realized APC and pre-equalizer circuit, and their operation principle and test results. In analog optical transmitter, constant lasing power control, free of signal clipping and linearity are important considerations. We examined pre-equalizer and APC(Automatic Power Control) circuit to improve the analog optical transmitter performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.7A
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• pp.1057-1062
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• 2000

Allow me to introduce the development of an FM transmitter. The transmitter uses millmeter waves at the frequency of 60 GHz, and it can produce as much as 20 mW power with the band width of 1 GHz. The great feature of the FM transmitter is that it has been created by the special technique of utilizing the NRD (non radiative dielectric) waveguide. The advantage of adopting the NRD waveguide is that it can significantly reduce transmission loss. We can construct a small-size NRD guide transmitter in a simple way that has superb transmission performance. The NRD guide transmitter is very useful for CATV transmission or transmission over a wide range. In addition, the transmitter has almost the same band width as optical communication, and the data transmission speed of the transmitter is faster than that of optical communication. A transmitter with these merits would be highly appreciated as a way of ultra-highspeed communication network over short distances.

• 한국정보통신설비학회:학술대회논문집
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• 2006.08a
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• pp.15-18
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• 2006

We have proposed a broadband analog feedforward optical transmitter using a wideband $180^{\circ}$ hybrid coupler instead of conventional frequency-sensitive phase shifter with the narrow bandwidth property using a wideband $180^{\circ}$ hybrid coupler, the wide-band linearization technique enhances the linearity of the feedforward optical transmitter. In two-tone cases, the $3^{rd}-IMD$ products was enhanced more than 10 dB in 385 MHz range(1.375$\sim$l.76 GHz).