• Proceedings of the IEEK Conference
• /
• 2001.06a
• /
• pp.209-212
• /
• 2001

We Propose a novel structure add/drop multiplexer based on an all-fiber Mach-Zehnder interferometer and fiber Bragg grating. In this structure, wavelength separation is achieved by adjusting the amount of the phase shift in the Mach-Zehnder interferometer. The proposed add/drop multiplexer drops a part of signal at a specific wavelength and transmit the remnant of the signal to the different node separated wavelength in WDM network.

• ETRI Journal
• /
• v.32 no.2
• /
• pp.248-254
• /
• 2010

We demonstrate a linear bus wavelength-reused gigabit wavelength-division multiplexing passive optical network (WDM-PON) with multiple optical add-drop nodes. A commercially available reflective semiconductor optical amplifier-based WDM-PON has a sufficient power budget to provide multiple optical add/drop nodes in 16 WDM channels. Sixteen 1.25 Gb/s WDM channels are successfully transmitted over 20 km of single-mode fiber with four optical add/drop multiplexers, even with 32 dB reflection and chromatic dispersion in the link.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.37 no.5
• /
• pp.49-54
• /
• 2000

We propose a new structure of bidirectional add/drop multiplexer that is a key component to implement bidirectional ring network. The proposed bidirectional add/drop multiplexer is based on fiber Bragg gratings. In experiment, we demonstrate the operation of the proposed bidirectional add/drop multiplexer in optical spectrum domain.

• Proceedings of the Optical Society of Korea Conference
• /
• 2007.07a
• /
• pp.355-356
• /
• 2007

• Proceedings of the Optical Society of Korea Conference
• /
• 2004.02a
• /
• pp.276-277
• /
• 2004

• Proceedings of the KIEE Conference
• /
• 1996.07b
• /
• pp.1286-1288
• /
• 1996

An add/drop control chip for SDH transmission system has been designed in AT&T 0.5um CMOS ORCA FPGA. This device plays an important role in achieving self-healing ring operation which protects against failure. After this device receives each 24-ch AU-3 signals from the west, east, and add parts, it outputs each 24-ch switched signals through the control data of system control port. This device consists of eight sub-part such west/east transmitting part, west/east receiving part, add/drop control part, AIS control part, and CPU interface part. The designed device is capable to ring networks as well as linear networks.

• Korean Journal of Optics and Photonics
• /
• v.20 no.4
• /
• pp.217-222
• /
• 2009

In this paper, a low-cost hybrid-integrated tunable laser is realized using a polymer-ring resonator-based add/drop filter reflector and a reflective semiconductor optical amplifier. The add/drop filter reflector, composed of a double-ring resonator with different radii, can have characteristics of selective wavelength reflection and wide wavelength tuning with an aid of vernier effect derived from the radii difference. By hybrid-integrating the reflective semiconductor optical amplifier with the add/drop filter reflector, a tunable laser can be realized through an active alignment method. The hybrid laser exhibited a single mode lasing with side mode suppression ratio of 26 dB and full width half maximum of 0.03 nm. In addition, applying a low current as small as 25 mA onto electrodes over add/drop filter reflector, a wavelength tuning range of 17 nm could be obtained.

• Korean Journal of Optics and Photonics
• /
• v.18 no.3
• /
• pp.216-220
• /
• 2007

A widely tunable add/drop filter composed of double ring resonators is implemented with high-index-contrast polymer waveguide. To enhance the productivity, directional couplers are designed to have good fabrication tolerance. The refractive indices of the core and cladding in the 1550 nm wavelength are 1.51 and 1.378, respectively. Drop response in comparison with neighborhood peak gets enhanced by more than 2.9 dB at the wavelength where both rings resonate. This filter can be used to build widely tunable laser diode through hybrid-integration with reflective SOA.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.8 no.4 s.23
• /
• pp.152-158
• /
• 2005

In this paper, we have proposed a fuel metering unit of ai breathing engine. The proposed valve system consists of a constant pressure drop valve and a metering valve, which are controlled by servovalve. We carried out nonlinear and linear analysis, computer simulation and experimentation to find effects of some factors on system performance. Analysis and experimental results show a good agreement. It is also shown that the system stability is affected by pressure drop of metering valve and inlet pressure of injectors.

• Journal of the Optical Society of Korea
• /
• v.12 no.3
• /
• pp.157-161
• /
• 2008

A wavelength-selective reflector, composed of a double-ring-resonator add/drop filter and a loop-back mirror at the drop port to be used for a hybrid-integrated tunable laser is designed and fabricated. High-index-contrast polymer waveguide is used to realize a compact device as small as $2mm{\times}0.4mm$. The radii of the rings are slightly different from each other to obtain a wide wavelength tuning via a vernier effect. Peak reflectivity is measured to be 52% for TE mode and polarization-dependent wavelength shift is 0.95 nm. The tuning range is measured to be about 42 nm for applied current as small as 46 mA.