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A theoretical model for simulating widely tunable sampled-grating distributed Bragg reflector (SGDBR) lasers has been developed. The model integrates both time-domain traveling-wave method and frequency-domain transfer-matrix method into a single procedure. The active region of the device is still operated in the conventional time domain, while the passive parts are firstly performed by the transfer-matrix method and then transformed to the time domain via digital filters. Both the static and dynamic characteristics of SGDBR lasers, such as L-I curve, output spectrum, tuning characteristics, large-signal modulation, and dynamic wavelength switching, can be clearly visible in our model and in qualitative agreement with the published experimental results.

By using the supercell lattice method, we investigate the influence of the squeezing lattice on the birefringence characteristics of photonic crystal fibers (PCFs). We first define the concept of squeezing ratio and then present a model, with which several types of PCFs are simulated. Simulation results show that the squeezing of PCFs' lattice with the uniform air holes in the cladding can break the multifold symmetry of PCFs and make PCFs highly birefringent. Furthermore, it is reported for the first time to our knowledge that the polarity of PCFs' birefringence can change several times as the air-hole diameter changes.

The impact of polarization dependence loss (PDL) on the degree of polarization (DOP) feedback signal in polarization mode dispersion (PMD) compensation is analyzed. PDL affects DOP only in the presence of PMD, and in the presence of PMD and PDL, DOP relates not only to both PMD and PDL vectors but also to the principal states of polarization (SOPs) components of the output signal; on the other hand, it adds new frequency dependence and is no longer independent of system bit rate. The PDL minimum endangering PMD compensation is determined by the step size of the PMD compensating algorithm and the differential group delay (DGD) value in optical fiber systems. DOP could no longer act as the feedback signal in PMD compensation unless the PDL in the fiber system has been effectively eliminated before PMD compensation.

Thin film filters (TFFs) are minimum phase filters, and the Hilbert transform law is related to the relationship between a TFF’s amplitude and phase response. It should be possible to obtain the phase response from the amplitude response by this law, but the Cauchy integral is too complex to calculate the phase response directly. In this paper, a method to reconstruct the phase response from the amplitude response was proposed, and then the group velocity delay and the chromatic dispersion of a TFF could also be obtained just by simple calculations. An experimental setup based on the RF modulation was designed. The test results were in good agreement with the theoretical value within passband, as determined by contrast analysis, and the validity of the method was proven. In addition, the dispersion characteristic of TFFs was also analyzed.

A dynamic theoretical model has been proposed for simulating the wavelength switching performance of widely tunable sampled-grating distributed Bragg reflector lasers. The active region of the device is still operated in time domain while the passive parts are first modeled by transfer-matrix method and then transformed into the time domain via digital filter approach. The switching performance and corresponding mode-competition behaviors can be clearly demonstrated by the transient spectrum traced by the switching time.

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A theoretical model is presented for simulating the sampled grating distributed Bragg reflector (SGDBR) laser integrated with semiconductor optical amplifier (SOA) and Mach-Zehnder (MZ) modulator. In this model, the active and passive sections are processed separately. The active region of laser and the SOA section are modeled by time domain traveling wave (TDTW) method. While the spectral properties of the SG and the MZ modulator are firstly calculated by Transfer-Matrix Method (TMM) and Beam Propagation Method (BPM), respectively, and then transformed into time domain using digital filter approach. Furthermore, the nonuniform carrier-dependence of gain and refractive index are also incorporated via Effective Bloch Equations (EBE). Compared with the full time-domain method, our model would be more flexible and efficient. The static and modulation performances of device are successfully simulated. This indicates that it can be a powerful platform for investigating the complex Photonic Integrated Circuits (PICs).

In this paper, a modified stacking method to fabricate photonic crystal fibers with squeezed lattice is presented, for the first time to our knowledge. This modified method can realize different structures of photonic crystal fibers with different expected squeezing ratios. The influences of the structural parameters on the squeezing ratio and birefringence are separately discussed in detail. Moreover, the birefringence characteristics of such photonic crystal fibers are simulated by using supercell lattice method.

Thin Film Filters (TFFs) are minimum phase filters, and the Hilbert Transform law is related to the relationship between a TFF's amplitude and phase response. It should be possible to obtain the phase response from the amplitude response by this law, but the Cauchy Integral is too complex to calculate the phase response directly. In this paper, a method to reconstruct the phase response from the amplitude response was proposed, and then the group velocity delay and the chromatic dispersion of a TFF could also be obtained just by simple calculations. An experimental setup based on the RF modulation was designed. The test results were in good agreement with the theoretical value within passband, as determined by contrast analysis, and the validity of the method was proven. In addition, the dispersion characteristic of TFFs was also analyzed.

The theoretical model of DOP degraded by PMD is presented, with which one can analyze and maximize DOP directly from two factors, the magnitude and the direction of the PMD vector. According to this, one method to counteract PMD of the link is adjusting the compensating vector’s magnitude to achieve a zero-magnitude total PMD vector in the system, another is changing the vector’s direction adaptively to make the input signal align with the total PMD vector. Further, the NRZ signal DOP property degraded by PMD and the system’s BER against the change of PMD are obtained in the first experiment, also, the PMD compensation performance-degradation as the scrambling rate is increased is studied in the second experiment, in which it is concluded that the scrambling rate of polarization state has an important impact on a reliable, repeatable PMD compensation in a reasonably short time.

Current optical communication systems are more and more relying on the advanced opto-electronic components. A series of revolutionary optical and optoelectronics components technology accounts for the fast progress and field deployment of high-capacity telecommunication and data-transmission systems. Since 1990s, the optical communication industry in China entered a high-speed development period and its wide deployment had already established the solid base for China information infrastructure. In this presentation, the main progress of optoelectronics components and technology in China are reviewed, which includes semiconductor laser diode/photo receiver, fiber optical amplifier, DWDM multiplexer/de-multiplexer, dispersion compensation components and all optical network node components, such as optical switch, OADM, tunable optical filters and variable optical attenuators, etc. Integration discrete components into monolithic/hybrid platform component is an inevitable choice for the consideration of performance, mass production and cost reduction. The current status and the future trends of OEIC and PIC components technology in China will also be discuss mainly on the monolithic integration DFB LD + EA modulator, and planar light-wave circuit (PLC) technology, etc.

This paper presents a novel optical circulator configuration which only employs Faraday rotators to complete light polarization plane’s rotation. By using Jones matrices, the insertion loss and isolation are evaluated. The results show that the isolation is obviously increasing with an increase of the rotation errors of the rotators. A 3-port circulator has been fabricated and achieved an insertion loss lower than 0.8dB and an isolation over 45dB.

In this paper, a novel hybrid passive component for EDFA was reported. This component integrated the 1550 nm polarization independent optical isolator and the 980/1550 nm pump WDM within a single compact case, and realized the reduction of insertion loss, cost and package size. The following techniques were adopted in fabricating this component: (1) high efficiency beveled end-face off-axis coupling between twin core ferrule and GRIN rod; (2) the pump WDM is based on GRIN rod and optical interference filter; (3) the optical polarization independent isolator using birefringence wedge, etc. This component was packaged in an ordinary isolator case as small as (Phi) 8 X 40 mm. The insertion loss of signal is less than 0.9 dB; the insertion loss of pump is less than 0.8 dB; the isolation of the built in isolator is more than 42 dB with +/- 15 nm pass-band and the return loss is more than 50 dB. This component has shown very stable performance against the environmental changes. It had been applied to a single forward pumped EDFA module, and has achieved the following good performance: more than 29 dB small signal gain, less than 5 dB noise figure, more than +10 dBm output power. The EDFA module has the dimension largely reduced to 15 X 100 X 130 mm.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.