Ken-Ichi Suzuki

Wide bandwidth and long distance WDM transmission using highly gain-flattened hybrid amplifier

A 1.5-dB gain-flatness over 67 nm is achieved with a novel hybrid amplifier comprised of a distributed Raman amplifier pumped at two wavelengths and an erbium-doped fluoride fiber amplifier. Fourteen 2.5-Gb/s signals spanning 65 nm are successfully transmitted over 900 km using the new amplifiers. Low-noise characteristics compared to the same transmission line with discrete erbium-doped fiber amplifiers are also confirmed.

Ultrawide 75-nm 3-dB gain-band optical amplification with erbium-doped fluoride fiber amplifiers and distributed Raman amplifiers

An extremely large 3-dB gain-bandwidth of 75 nm (1531-1606 nm) is achieved with a partially gain-flattened erbium-doped fluoride fiber amplifier and a distributed Raman amplifier. The Raman amplifier consists of a 85-km dispersion-shifted fiber (transmission fiber) and a practical 1505-nm Fabry-Perot laser diode pump. 9/spl times/2.5 Gb/s wavelength-division-multiplexing (WDM) transmission is successfully demonstrated using two 75-nm gain-band amplifiers as in-line and preamplifiers.

Amplified gigabit PON systems [Invited]

Feature Issue on Passive Optical Network Architectures and TechnologiesWe describe how a passive optical network (PON) extender box can be implemented at standard PON wavelengths (1310 and 1490nm) using either optical fiber amplifiers (praseodymium and thulium) or semiconductor optical amplifiers to further increase the physical reach and split of a current standardized PON system such as a G-PON or GE-PON. The transparency to PON protocol of this approach means no changes to the existing standards are required. This is attractive as operators and vendors are keen to fully exploit the investment made in current PON standards.

80 Gb/s optical soliton transmission over 80 km with time/polarization division multiplexing

Time/polarization-division multiplexed optical solitons are successfully transmitted at 80 Gb/s over an 80 km dispersion-shifted single-mode-fiber. The 80 Gb/s optical pulse trains are generated by optically multiplexing 10 Gb/s gain-switched pulse trains. The transmitted solitons are demultiplexed with a polarization beam splitter and two intensity-modulators driven by a 10 Gb/s electrical timing recovery circuit. No error-rate floor is observed.<<ETX>>

160 Gb/s sub-picosecond transform-limited pulse signal generation utilizing adiabatic soliton compression and optical time-division multiplexing

0.8 ps TL pulses are successfully generated from a gain-switched DFB-LD by adiabatic soliton compression using a dispersion decreasing fiber (DDF). The compression ratio can be controlled using the peak input power into the DDF. We obtain a 10/spl times/2/sup n/ Gb/s pulse stream by optically multiplexing the compressed pulses with a Mach-Zehnder (MZ) interferometer type multiplexer, in which n can be freely selected from 1 to 4 by controlling the coupling ratios of the couplers in the MZ interferometers. By using the demonstrated techniques, we can multiplex the initial pulse stream up to 160 Gb/s at the noninterfering duty factor of 0.2.<<ETX>>

Adiabatic soliton compression of gain-switched DFB-LD pulse by distributed fiber Raman amplification

Using a dispersion-shifted single-mode fiber pumped by laser diodes as a distributed fiber Raman amplifier, the authors adiabatically compressed transform-limited (TL) pulses generated by a gain-switched distributed-feedback laser diode followed by linear compression and a spectral window. The initial TL pulses were successfully compressed asymptotically to almost pure solitons as short as 3.6 ps at the 2.4 dB total gain of a distributed fiber Raman amplifier, even without using solitons as the initial pulses. The experimental results are well supported by numerical calculations made with the beam propagation method.<<ETX>>

20 Gb/s optical soliton data transmission over 70 km using distributed fiber amplifiers

20 Gb/s optical soliton data transmission is demonstrated over 70 km. Highly efficient distributed Raman amplifiers for fiber-loss compensation are realized by using high Delta n dispersion-shifted single-mode fibers pumped by laser diodes. To achieve high bit rate transmission, optical multiplexing and demultiplexing techniques are also employed. The bit error rate (BER) performance dependence on the input peak power of the optical pulse is measured. No power penalty can be seen at the input peak power required for transmitting optical solitons while the BER performance degrades when decreasing the input peak power.<<ETX>>

60 km, 256-split Optically-amplified PON Repeatered Transmission using 1.24 Gbit/s Upstream and 2.5 Gbit/s Downstream PON system

We successfully demonstrate a 60 km optically-amplified PON repeatered transmission experiment using commercial 1.24 Gbit/s upstream and 2.5 Gbit/s downstream PON systems with an optical-amplifier-based PON repeater, a burst-mode upstream pre-amplifier, and a combination of 4x and 64x splitters.

60 Gb/s/spl times/2 ch time/polarization-multiplexed soliton transmission over 154 km utilizing an adiabatically compressed, gain-switched, DFB-LD pulse source

Time/polarization-division multiplexed optical solitons are successfully transmitted at 120 Gb/s over 154 km. The transmitted solitons are generated from an adiabatically compressed transform-limited gain-switched DFB-LD pulse source, and demultiplexed with a polarization beam splitter and three cascaded intensity-modulators driven by a 7.5 GHz timing recovery circuit. No error-rate floor is observed.<<ETX>>

Field Trial of Long-Reach and High-Splitting λ-Tunable TWDM-PON

This paper presents the worlds first field trial of a 40-km reach and over 512-split symmetric-rate 40-Gbit/s λ-tunable time and wavelength division multiplexing passive optical network (TWDM-PON) that utilizes our newly developed high-speed λ-tunable optical network unit transceivers and automatic gain controlled semiconductor optical amplifier-based PON extender for repeater and central office use. The upstream signals for C-band and downstream signals for L+-band in our developed λ-tunable TWDM-PON comply with the wavelength plan of ITU-T G.989 series. In a field trial, we successfully demonstrate error free λ-tunable transmission for the 40-km reach and 1024-split (maximum number) symmetric-rate 40-Gbit/s λ-tunable TWDM-PON over installed standard single-mode fiber links, and advanced network functions such as dynamic load balancing, incremental system upgrade, optical subscriber unit protection, and OLT equipment power saving are also confirmed.