Mahn Yong Park

Bidirectional WDM-PON based on gain-saturated reflective semiconductor optical amplifiers

We propose a bidirectional wavelength-division-multiplexed passive optical network by employing gain-saturated reflective semiconductor optical amplifiers (RSOAs) for wavelength-independent optical network terminals. The fabricated RSOA module has the input saturation power less than -13 dBm and its saturated gain higher than 13 dB within the C-band for arbitrary polarization states. The upstream signals are generated by remodulating the downstream signals whose modulation amplitude is squeezed through gain-saturated RSOAs. We present experimental results on bidirectional transmission with 1.25 Gb/s for upstream and 2.5 Gb/s for downstream data rates over 20-km transmission distance.

Tunable external cavity laser based on polymer waveguide platform for WDM access network

We developed a wide-range wavelength tunable external cavity lasers based on a polymer waveguide platform for use in wavelength-division-multiplexing (WDM) access networks as a low-cost light source. The lasing wavelength is tuned over 13 nm by thermally changing the reflection spectrum of the polymer waveguide Bragg grating with a heater. With the sidemode suppression ratio higher than 30 dB, it can support 16 WDM channels spaced by 100 GHz. The directly modulated 1.25-Gb/s data streams were successfully transmitted over the single-mode optical fiber link of 20 km.

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

Frequency detuning effects in a loop-back WDM-PON employing gain-saturated RSOAs

We report that, in a loop-back wavelength-division-multiplexed passive optical network link with gain-saturated reflective semiconductor optical amplifiers, the upstream performance is strongly affected not only by the gain saturation but also by the selective spectral filtering caused by the frequency difference between the optical downstream signal and the cascaded filters passband. We experimentally investigate these effects and propose to use an additional negatively detuned optical filter at an optical network terminal to improve the upstream transmission performance

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.

Widely Tunable Surface-Relief Bragg Gratings in Polymer Waveguide with Low Power Consumption

A polymer waveguide Bragg grating was fabricated with non-contact phase-mask. By employing the silicon trench below the grating segment, it was able to tune the wavelengths over 30 nm at a rate of-0.28 nm/mW.