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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.

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).

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.