Tunable Dispersion Slope Compensator Research Articles

Tunable dispersion slope compensator using two uniform fiber Bragg gratings mounted on S-shape plate

We propose and experimentally demonstrate a novel method for tunable dispersion slope compensation. We use two uniform fiber Bragg gratings (FBGs), a spatially designed S-bending stage and 4-port circulator. Two FBGs are mounted on each surface of a metal plate along the calculated quadratic curve. The dispersion slope (DS) can be tuned by adjusting a nonlinear strain along two uniform FBGs without changing second order dispersion as well as the central wavelength. In the experiment, a DS tuning range from -13.9 to -54.8 ps/nm(2) is achieved with the bandwidth of larger than 2.0 nm.

Novel complex gratings with third-order group-delay variations for tunable pure dispersion slope compensation

We present a novel tunable dispersion compensator that can provide pure slope compensation. The approach uses two specially designed complex fiber Bragg gratings (FBGs) with reversely varied third-order group delay curves to generate the dispersion slope. The slope can be changed by adjusting the relative wavelength positions of the two FBGs. Several design examples of such complex gratings are presented and discussed. Experimentally, we achieve a dispersion slope tuning range of +/- 650 ps/nm(2) with > 0.9 nm usable bandwidth.

Tunable chromatic dispersion and dispersion slope compensator using a planar lightwave circuit lattice-form filter

A tunable chromatic dispersion and dispersion slope compensator is proposed that has a single lattice-form filter configuration. Wavelength dependence is intentionally added to its tunable couplers, which produces dispersion slope compensation in addition to the dispersion compensation. Dispersion tunability of +/- 500 ps/nm and a slope of -4.9 ps/nm(2) over 40 GHz are successfully demonstrated, thus meeting the requirement for 40 Gbits/s differential quadrature phase shift keying transmission with an 80 km long nonzero dispersion-shifted fiber.

Two-User 150-km Field Fiber Security Enhanced SPECTS O-CDMA Transmission

We demonstrate two-user error-free performance of security enhanced spectral phase-encoded time-spreading optical code-division multiple-access across a 150-km field fiber link. The testbed incorporates a 64-mode optical frequency comb source, a fully integrated silica arrayed waveguide grating spectral phase encoder/decoder, and a tunable dispersion slope compensator. Physical layer security is enhanced by using a bright code/dark code modulation format

Tunable Dispersion and Dispersion Slope Compensator Using Strain-Chirped Fiber Bragg Grating

We propose a tunable dispersion and dispersion slope compensator based on induced strain-chirp in a uniform fiber Bragg grating. A specially designed mechanical rotator concatenated with a metal beam with linear thickness variation along its height was used to induce a quadratic strain gradient along the grating. We successfully demonstrated the dispersion and dispersion slope change by adjusting the rotation angle and feasibility of dispersion and dispersion slope compensation at 160-Gb/s nonreturn-to-zero transmission by simulation

80.8-km BOSSNET SPECTS O-CDMA Field Trial Using Subpicosecond Pulses and a Fully Integrated, Compact AWG-Based Encoder/Decoder

We successfully demonstrate a spectral phase-encoded time-spreading (SPECTS) optical code-division multiple-access (O-CDMA) field trial on an 80.8-km link within the Boston-South Network (BOSSNET) using a fully-integrated, polarization-independent arrayed-waveguide grating (AWG)-based encoder/decoder. The subpicosecond pulse source is based on an ultrastable optical frequency comb generator employing dispersion-decreasing fiber. A novel tunable dispersion-slope compensator enables the use of subpicosecond pulses without extensive characterization of the field-deployed fiber. Bit-error rate (BER) and Ethernet traffic statistics are presented.

Tunable dispersion slope compensator using a chirped fiber Bragg grating tuned by a fan-shaped thin metallic heat channel

An electrically tunable dispersion slope compensator using a chirped fiber Bragg grating tuned by quadratic temperature distribution is demonstrated. A fan-shaped thin metallic heat channel was used to generate a quadratic temperature gradient along the grating. By controlling the temperature of inner and outer boundaries of the heat channel, we achieved a dispersion slope from -60.82-65.89 ps/nm/sup 2/ for 1.2-nm bandwidth. The dispersion slope compensation in 160-Gb/s return-to-zero transmission is demonstrated by simulation.

160-Gb/s tunable dispersion slope compensator using a chirped fiber Bragg grating and a quadratic heater

We demonstrate a tunable dispersion slope compensator using a linearly chirped fiber Bragg grating and a thin-film heater that provides a variable quadratic temperature gradient along the grating. We achieved 2-10-ps/nm/sup 2/ compensation over 3 nm suitable for 160-Gb/s return-to-zero signals.

Spectrum Tuning of Fiber Bragg Gratings by Strain Distributions and Its Applications

We report tunable optical devices based on fiber Bragg gratings (FBGs), whose filtering characteristics are controlled by strain distributions. These devices include a widely wavelength tunable filter, a tunable group-velocity dispersion (GVD) compensator, a tunable dispersion slope (DS) compensator, and a variable-bandwidth optical add/drop multiplexer (OADM), which will play important roles for next-generation reconfigurable optical networks.

Tunable Dispersion and Dispersion Slope Compensator Using Novel Gires–Tournois Bragg Grating Coupled-Cavities

We report on the first realization of lattice-coupled all-fiber Gires-Tournois etalons for chromatic dispersion (CD) compensation. CD tunability is obtained by cascading two fiber Bragg grating superstructures. We show that the use of one superstructure with lattice-coupled cavities leads to a 60% tunability increase compared to single cavity designs. Dispersion slope compensation is proposed and demonstrated using a temperature gradient.

A FBG etalon in transmission based tunable dispersion slope compensator

We analyze the dispersion properties of FBG etalon in transmission mode. The application of FBG etalon for dispersion slope compensation in transmission mode is proposed. In our design, the dispersion slope of the FBG etalon transmission channels ranges from −1.8 to −48 ps/nm2. The effective bandwidth of each channel is 40 GHz. A tunable dispersion slope compensator based on this FBG etalon is presented. Strain is applied to shift the channels and achieve the dispersion slope tuning at a certain wavelength. Experimental results substantiate the analysis. The proposed device is compact and has low insertion loss and simple tuning mechanism.

Tunable Dispersion Slope Compensator With a Chirped Fiber Grating and a Divided Thin-Film Heater for 160-Gb/s RZ Transmissions

We have developed the tunable dispersion slope compensator with a chirped fiber grating and a divided thin-film heater composed of 32 thin-film heaters for single-channel 160-Gb/s return-to-zero (RZ) transmission. We successfully demonstrated the dispersion slope change between -20 and +20 ps/nm/sup 2/ and ability of this dispersion slope compensation in 160-Gb/s RZ transmission by the simulations.

A novel tunable dispersion slope compensator based on nonlinearly thermally chirped fiber Bragg grating

We propose a novel method for introducing a chirp on a fiber Bragg grating. Applying a controllable nonlinear temperature gradient across a uniformly written Bragg grating chirps it nonlinearly to realize a tunable dispersion slope compensator for waveform distortion compensation. This scheme allows an adjustable, repeatable, stable, and precise nonlinear chirp onto the grating. The dispersion slope of the device was tuned from −37.06 to −199.45 ps/nm 2, with observed GDR as low as ±5 ps.

Tunable interchannel broad-band dispersion-slope compensation for 10-Gb/s WDM systems using a nonchannelized third-order chirped FBG

We demonstrate tunable dispersion-slope compensation using a single broad-band nonchannelized fiber Bragg grating. Tunability of the dispersion slope is achieved by stretching the grating, which has a third-order time-delay variation with wavelength, thereby causing a second-order variation in dispersion. Although this nonlinear dispersion characteristic causes some inherent mismatch between the grating and real fiber links, the induced errors are negligible in 10-Gb/s systems. Dispersion-slope tunability of /spl sim/65 ps/nm/sup 2/ is achieved using a grating with dispersion variation of up to 400 ps/nm over a 3.5-nm usable bandwidth. Using this grating, we show over 10-dB improvement in the worst-case channel in a 10-Gb/s return-to-zero system. Two gratings are cascaded in order to double the dispersion values that can be compensated by the grating.

Tunable dispersion slope compensation for 40-Gb/s WDM systems using broadband nonchannelized third-order chirped fiber Bragg gratings

We demonstrate tunable dispersion slope compensation using broadband nonchannelized third-order chirped fiber Bragg gratings (FBGs) for 40-Gb/s wavelength-division-multiplexed (WDM) systems. The slope is tuned by stretching as it has a third-order time delay variation with wavelength, and thus a second-order dispersion-wavelength curve. Calculation results include the examples of the slope tuning in addition to the interchannel dispersion differences and the slope tuning ranges with respect to the wavelength in a single grating. To verify the functionality of the third-order grating, we prepare a third-order grating with a dispersion variation of up to 400 ps/nm over the 3.5-nm usable bandwidth, and a dispersion slope tuning range of /spl sim/65 ps/nm/sup 2/ is achieved. For 40-Gb/s systems, two new gratings are designed and inversely cascaded to eliminate the inherent errors originating from the deleterious higher-order dispersion components in a single grating. The slope tuning range is -20 to +20 ps/nm/sup 2/ over the 5-nm usable bandwidth. A /spl sim/10-dB power penalty improvement is achieved and the BER floor is eliminated for the worst-case channel after transmission through a 170-km link using dispersion shifted fiber (DSF) with a 4/spl times/40-Gb/s RZ data stream.

Integrated all-pass filters for tunable dispersion and dispersion slope compensation

New integrated optical all-pass filters are presented that can be used for tunable dispersion compensation, dispersion slope compensation, and as building blocks in tunable bandpass filters. The dispersion slope compensation capability is demonstrated using ring resonators in /spl Delta/=2% Ge-doped silica planar waveguides. In addition, a tunable four-stage filter with free-spectral range (FSR)=25 GHz, a passband width of 14 GHz (0.56/spl times/FSR), and D=1800 ps/nm is reported.