Fiberpro (South Korea)

We demonstrate a simple all-fiber photonic phase detector that can measure the phase (timing) difference between an optical pulse train and a microwave signal with subfemtosecond resolution and -60 dB-level amplitude-to-phase conversion coefficient. It is based on passive phase biasing of a Sagnac loop by the intrinsic phase shift of a symmetric 3×3 fiber coupler. By eliminating the necessity of magneto-optic components or complex radio frequency (RF) electronics for phase biasing of the Sagnac loop, this phase detector has potential to be implemented as an integrated photonic device as well. When using this device for synchronization between a 250MHz mode-locked Er-fiber laser and an 8GHz microwave oscillator, the minimum residual phase noise floor reaches <-154 dBc/Hz (at 8GHz carrier) with integrated root mean square (rms) timing jitter of 0.97fs [1Hz-1MHz]. The long-term rms timing drift and frequency instability are 0.92fs (over 5000s) and 4×10-19 (at 10,000s averaging time), respectively.

Remote transfer of high-resolution video information finds more applications in detached display applications for large facilities such as theaters, sports complex, airports, and security facilities. Active optical cables (AOCs) provide a promising approach for enhancing both the transmittable resolution and distance that standard copper-based cables cannot reach. In addition to the standard digital formats such as HDMI, the high-resolution, long-distance transfer of VGA format signals is important for applications where high-resolution analog video ports should be also supported, such as military/defense applications and high-resolution video camera links. In this presentation we present the development of a compressionless, high-resolution (up to WUXGA, 1920x1200), long-distance (up to 2 km) VGA extenders based on serialized technique. We employed asynchronous serial transmission and clock regeneration techniques, which enables lower cost implementation of VGA extenders by removing the necessity for clock transmission and large memory at the receiver. Two 3.125-Gbps transceivers are used in parallel to meet the required maximum video data rate of 6.25 Gbps. As the data are transmitted asynchronously, 24-bit pixel clock time stamp is employed to regenerate video pixel clock accurately at the receiver side. In parallel to the video information, stereo audio and RS-232 control signals are transmitted as well.

To increase the transmission capacity of a wavelength-division multiplexed (WDM) system, numerous works concentrated on the extension of erbium-doped fiber amplifier (EDFA) bandwidths. Recent reports showed that ultra-wide bandwidths, wider than 80nm were possible by using both the C-band (1550nm band) and L-band (1580nm band). System experiments showed the possibility of their application to real systems. In spite of the large bandwidth of the single ultra-wideband EDFA, bandwidth-distance products on the demonstrations limited to less than 24K nm-km (55.6nm/spl times/400km, 40nm/spl times/600km). The key issues are how to maintain the flat gain with transmission distance increase and how to achieve low noise figure for L-band EDFAs. In the work, we demonstrate a 124K nm-km (52nm/spl times/ 2400nm) transmission of 51 channels at 17dB of the optical signal to noise ratio (OSNR), by employing a low-noise wideband amplifier in conjunction with an all-fiber acousto-optic tunable filter. We have employed a re-circulating EDFA loop which consists of acousto-optic modulators, a single mode fiber, an attenuator, an isolator, a polarization scrambler, and an wideband EDFA (WEDFA).