Joon Young Huh

Field Trial of 112 Gb/s Dual-Carrier DQPSK Channel Upgrade in Installed 516 km of Fiber Link and ROADM

A field trial of 100GE signal transmission using dual-carrier differential quadrature phase shift keying (DC-DQPSK) based optical transceiver is demonstrated for 100 Gb/s metro area network. Neither high-end ADC/DSP nor fast optical polarization tracking is required in the DC-DQPSK based optical transceiver, which results in low electrical power consumption of ~ 35 W. The measured OSNR sensitivity of DC-DQPSK optical transceiver at the BER of 10- 3 is 18.3 dB. After the transmission through 516 km of installed fiber and ROADM, an error-free transmission of 100GE signal over 106 hours with OTU4 framer and forward error correction (FEC) decoding proves feasibility of DC-DQPSK optical transceiver for 100G metro network applications.

Analysis of dimensional tolerance for an optical demultiplexer of a highly alignment tolerant 4 × 25 Gb/s ROSA module

We have developed a 4 × 25 Gb/s ROSA (receiver optical sub-assembly) module for 100G Ethernet optical transceiver. This ROSA module has very large alignment tolerance of more than ± 250 µm between the optical DMUX (demultiplexer) and four photodiodes, for the reason it has the advantage of being easily assembled. The large alignment tolerance can be attributed to the dimensional tolerant optical DMUX, which is composed of four thin film filters attached to a parallelogram-shaped optic block. Since it is important to define the fabrication specifications for the dimension of the optic block, we analyze dimensional tolerance for the optic block using three-dimensional simulation. This parallelogram-shaped optical DMUX permits length tolerance of ± 300 µm and angular tolerance of ± 0.1°. The fabricated optical DMUX is estimated to have the angular error of less than 0.09°.

Analysis of PAM-N (N=4, 5, 6, 7 and 8) signals operating at 103.125 Gbps for next-generation Ethernet

We compare optical PAM-N (N=4, 5, 6, 7, and 8) signals operating at 103.12-Gbps. From the results, PAM-5 signal is more appropriate than other PAM-N signals by considering the effect of chromatic dispersion for 10-km SMF transmission using wavelength of LAN-WDM.

Highly alignment tolerant and high-sensitivity 100Gb/s (4 × 25Gb/s) APD-ROSA with a thin-film filter-based de-multiplexer

We investigate and demonstrate a 100-Gb/s (4x25-Gb/s) receiver optical sub-assembly (ROSA) based on avalanche photodiodes and a thin-film filter-based de-multiplexer. The overall alignment tolerances of the ROSA are relaxed to have larger than ± 25 μm by improving optical coupling structure. The receiver sensitivity of each lane is also measured to be less than -22.2 dBm, a record minimum to our knowledge, at the bit error ratio of 10-12 for 25.78-Gb/s NRZ signal.

OSNR monitoring technique based on four-wave mixing for polarization-division multiplex transmission

We propose and demonstrate a novel OSNR monitoring technique for polarization division multiplexed (PDM) transmission. This technique based on four-wave mixing in nonlinear medium can individually monitor the OSNR values of X-axis and Y-axis signals in 80-Gbps PDM-NRZ transmission with accuracy of 0.5 dB.