Jie-hyun Lee

Over 26-nm Wavelength Tunable External Cavity Laser Based on Polymer Waveguide Platforms for WDM Access Networks

We demonstrated a widely tunable hybrid-integrated external cavity laser on a polymer-based waveguide platform. The lasing wavelength was tuned over 26 nm by locally heating the surface-relief-type polymer waveguide Bragg grating fabricated by using the phase mask. The phase-control heater section was inserted between the laser diode and the Bragg grating for the fine wavelength tuning and the stable single-mode lasing. In the 100-GHz-spaced wavelength-division-multiplexing systems, the 1.25-Gb/s directly modulated data streams at each tuned 32 channel were successfully transmitted

First commercial service of a colorless Gigabit WDM/TDM hybrid PON system

We describe the first RSOA-based WDM/TDM hybrid PON system to enter commercial service. The system, consisting of a 16 × 1.25 Gb/s colorless Gigabit WDM-PON and a legacy TDM-PON with optical-electrical-optical converters, provides the triple-play service using fiber-to-the-home and fiber-to-the-node in a new residential area in Korea.

34.2: PMMA Buffer‐Layer Effects on Electrical Performance of Pentacene OTFTs with a Cross‐linked PVA Gate Insulator on a Flexible Substrate

In this paper we proposed for the first time a technique of poly-methylmethacrylate (PMMA) buffer layer insertion to overcome unsaturated output characteristics of OTFTs with cross-linked poly-vinylalcohol (PVA) gate insulators on a PET substrate. A 3:1 diluted PMMA buffer layer insertion resulted in saturated output characteristics and small shift of a threshold voltage in successive I-V measurements for OTFTs due to the enhancement of surface hydrophobicity on the gate insulator. The electrical performances of a threshold voltage, a subthreshold slope and on-off current ratio have been noticeably improved after PMMA buffer layers insertion. To our best knowledge, the highest mobility of 0.32 cm2/Vsec has been obtained among OTFTs fabricated with polymer gate insulators by spin coating processes on a PET substrate.

Demonstrations of RSOA based loop-back WDM-PON with 100 Gb/s (80 × 1.25 Gb/s) capacity employing spectrum sliced incoherent light injection

We have successfully demonstrated a loop-back WDM-PON with a 100 Gb/s (80×1.25 Gb/s) capacity using spectrally sliced ASE injected RSOA. To mitigate the RIN degradations, we proposed injection current adjustment, dispersion management and the use of receiver with optimized decision threshold level.

1.25 Gb/s operation of ASE injected RSOA with 50 GHz channel spacing by using injection current adjustment, dispersion management and receiver with decision threshold level control

We successfully demonstrated the 1.25 Gb/s operation of ASE injected RSOA with 50 GHz channel spacing by using the injection current adjustment, the dispersion management and the receiver with decision threshold level control. We could mitigate the RIN degradation caused by post filtering through the injection current adjustments, and also alleviate the dispersion induced RIN degradation by means of the dispersion management to take advantage of the insertion of dispersion compensating fiber (DCF). Finally, the use of optical receiver with optimized decision threshold level could eliminate some sorts of error floor which are attributed to unequal noise distribution at mark level.

Demonstration of Burst Amplified Uplink for RSOA-based WDM/TDM Hybrid PON Systems Using SOA as a Multi-Channel Preamplifier

We have demonstrated the feasibility of burst amplified uplink for single-¿ bidirectional RSOA-based WDM/TDM hybrid PON systems using SOA as a multi-channel preamplifier.

Effects of RSOA gain ripples on upstream transmission in a SML-seeded loop-back WDM-PON

In a SML-seeded loop-back WDM-PON, the upstream BER plots show variation of power penalty by 2 dB, depending on the difference of seed and ripple peak wavelength, which is related to the RSOA transient chirp.

2.5 Gbps Hybrid PON link Using RSOA Based WDM-PON and a Reach Extender

We presents the architecture of the 2.5 Gbps hybrid PON link which can increase of the transmission distance and link capability, and split ratio by using a colorless DWDM-PON and O/E/O based reach extender into an existing G-PON link. A RSOA based DWDM-PON to apply the feeder fiber can provide a link capacity of 32 larger that of a legacy G-PON. The reach extender converts the wavelength of DWDM-PON to G-PON through GTC frame regeneration at the remote node, and can provide a burst reset signal in order to extract upstream burst signal, simultaneously. The proposed hybrid PON enable a legacy G-PON to operate over the maximum 60 km distance with a 128-way split per WDM wavelength.

APC receptacle type cooled RSOA-TOSA for WDM-PON transceiver

APC receptacle type cooled RSOA-TOSA with low return loss and high coupling efficiency was successfully developed for field-deployed WDM-PON application.

Fabrication and performance analysis of cost-effective fiber grating lasers for WDM-PON systems

Fiber-Bragg-grating external cavity laser(FGL) modules were fabricated and experimentally analyzed. Proposed as a cost-effective solution for optical sources in the WDM-PON access network, FGL modules were packaged to TO-CAN type. We obtained a low threshold current of 13 mA, and an optical output power of 3.6 mW with a bias current of 60 mA at . The lasing wavelength dependencies on current and temperature were as small as 5.2 pm/mA and 30 pm/, respectively. These change rates of the wavelength with the temperature and current are smaller than those of the DFB laser. Single-mode oscillations with the side-mode suppression ratio(SMSR) over 30 dB are maintained above the threshold current level. The FGL modules can be directly modulated at 155 Mbps, PRBS(2 -1) NRZ signal. Through the BER plots, we did not see the significant degradations before and after the transmission over 20km of the SMF at 155 Mb/s.