Jonas Hansryd

Broad-band continuous-wave-pumped fiber optical parametric amplifier with 49-dB gain and wavelength-conversion efficiency

A broad-band continuous-wave (CW) pumped fiber-based parametric amplifier with 39 dB of internal gain and wavelength conversion efficiency, corresponding to a black box gain/efficiency of 38 dB, is demonstrated. Bit-error-rate (BER) measurements indicate performance comparable to erbium-doped fiber amplifiers (EDFAs). These amplifiers may thus find new applications in future lightwave systems.

Increase of the SBS threshold in a short highly nonlinear fiber by applying a temperature distribution

We evaluate numerically and experimentally the stimulated Brillouin scattering (SBS) threshold increase for a short, highly nonlinear GeO/sub 2/-doped fiber by applying different temperature distributions along the fiber. The temperature coefficient for the Brillouin frequency downshift is measured to 1.2 MHz//spl deg/C. A threefold SBS threshold increase is obtained for a 100-m long highly nonlinear fiber with a 140/spl deg/C temperature gradient. The proposed scheme is implemented in a wavelength converter based on fiber optical four-wave mixing (FWM). The SBS suppression scheme shows negligible influence on the FWM efficiency as well as the wavelength conversion bandwidth. The temperature coefficient for the zero dispersion wavelength is measured to 0.062 nm//spl deg/C.

High-performance optical-fiber-nonlinearity-based optical waveform monitoring

An all-optical waveform sampling system with simultaneous submilliwatt optical signal sensitivity (20-dB signal-to-noise ratio) and subpicosecond temporal resolution over more than 60-nm optical bandwidth is demonstrated in this paper. The optical sampling was implemented by four-wave mixing in a 10-m highly nonlinear fiber using a sampling pulse source with a sampling pulse peak power of only 16 W. The sampling performance was evaluated in terms of sensitivity, temporal resolution, and optical bandwidth with respect to fiber length, sampling pulse source wavelength offset from the zero-dispersion wavelength of the highly nonlinear fiber, sampling pulse peak power, and walk-off due to chromatic dispersion. This paper also presents a summary of the available methods to achieve polarization-independent optical sampling as well as a brief summary of the available sampling pulse sources viable for optical sampling.

O-TDM demultiplexer with 40-dB gain based on a fiber optical parametric amplifier

We demonstrate a broad-band time-division demultiplexer with inherent gain based on selective amplification in a fiber optical parametric amplifier. The parametric amplifier is pumped by a CW light source being sinusoidally intensity modulated by an optical Mach-Zehnder modulator. A switching window between 10% and 18% of the modulation period is measured over a 39 nm wavelength range with a demultiplexed fiber gain of up to 40 dB. Four-wave mixing based demultiplexing without wavelength conversion was achieved due to the high parametric gain. Bit-error-rate measurements show error-free demultiplexing at 40 to 10 Gb/s.

300 Gbit/s eye-diagram measurement by optical sampling using fiber based parametric amplification

300 Gbit/s optical signal eye-diagram measurements have been demonstrated for the first time by all-optical sampling using parametric amplification in a highly nonlinear fiber with a resolution of 1.6 ps. The measured eye-diagrams are updated in real-time.

Broadband CW pumped fiber optical parametric amplifier with 49 dB gain and wavelength conversion efficiency

Broadband, CW pumped fiber-based parametric amplifier with 49 dB of internal gain and wavelength conversion efficiency, corresponding to a net gain/efficiency of 38 dB, is demonstrated. BER measurements indicate performance comparable to EDFAs. These amplifiers may thus find new applications in future lightwave systems.

Long-term 160 Gb/s-TDM, RZ transmission with automatic PMD compensation and system monitoring using an optical sampling system

Long-term measurements (10 hrs) of a 160 Gbit/s, single wavelength, RZ-system with automatic PMD compensation are demonstrated for the first time. The 186 km dispersion managed transmission system performance is also, for the first time, quantified in terms of Q-value using a real-time eye-diagram monitor based on all-optical sampling.

Impact of PMD on four-wave-mixing-induced crosstalk in WDM systems

The impact of polarization-mode dispersion (PMD) on four-wave mixing crosstalk in wavelength-division-multiplexed (WDM) fiber systems is quantified on a commercial system. It is found that even a small amount of PMD reduces the benefit of using polarization-multiplexed channels for suppression of crosstalk. As a rule of thumb, it is suggested that polarization-multiplexed schemes are of significant interest only when system differential group-delay (DGD) is smaller than DGD <1/(4/spl Delta/f), where /spl Delta/f is the channel-spacing.

All-optical synchronous Q-measurements for ultra-high speed transmission systems

We have characterized a synchronous optical sampling system in terms of Q-values in an SNR-degraded system. The results were compared with an electrical sampling oscilloscope. The higher bandwidth of the optical system results in a lower Q for the same BER. The high sampling rate of the optical system eliminates in most cases the need for clock-recovery.

Measurement of the differential group delay in installed optical fibers using polarization multiplexed solitons

We experimentally demonstrate a new technique for measurement of the differential group delay (DGD) in optical fibers using polarization-division multiplexed (PDM) solitons: the change in the separation of orthogonally polarized solitons propagating along different principal axes in a fiber equals the DGD at the signal wavelength. Based on this principle, we use PDM solitons to measure the accumulated DGD at different distances along a 400-km installed fiber. The measured DGD exhibits the expected square-root-of-length dependence, corresponding to a polarization-mode dispersion of 0.26 ps/km/sup 1/2/. The results are in excellent agreement with those obtained by a commercial instrument utilizing Jones matrix eigenanalysis.