Abstract: Systems and methods for optical communications. In one implementation, a communications device is provided. The communications device includes an Optical domain Adaptive Dispersion Compensation Module (OADCM); an Electrical domain Adaptive Distortion Compensation Module (EADCM); and a controller coupled to, and operable to selectively control, both the OADCM and the EADCM.

Abstract: An apparatus is provided comprising a dual optical amplifier. The two optical amplifiers are integrated, in that they share at a set of optical, electrical, or opto-electrical components. The two optical amplifiers may share a pump laser. Alternatively, the optical amplifiers may share photo-detectors. Methods of controlling the signal strength of output signals are also provided. A chip-based integrated optical dual amplifier, using Erbium-Doped Waveguides, is also provided.

Abstract: According to the invention there is provided a method of controlling an optical communication system comprising an optical transmitter, an optical receiver and an optical fiber interconnecting the optical transmitter and the optical receiver, the method comprising determining the performance of the optical communication system and controlling at least one setting parameter of the optical transmitter according to the measured performance.

Abstract: A Re-Configurable Dispersion Compensation Module is provided. A new approach to the variable DCM, the RDCM combines existing optical switch technology with existing fixed DCM technology and advantageously also with existing TDCM technology into a programmable smart optical component. Advantageously Micro-Electrical Mechanical Switch (MEMS) optical switch technology may be used. The alternate RDCM technology provides a controller, and a set of controllable switches to employ a set of DCMs and TDCMs for adjusting the dispersion compensation along an optical signal path. This alternate RDCM technology mitigates the problems of conventional TDCMs, while fitting most of the requirements for high speed systems, and being of a compact size.

Abstract: A novel integrated multiple-rate optical time division multiplexing (OTDM) module is disclosed. An integrated set of modulators generates optical RZ signal streams which are then time-delayed by a set of integrated optical delay switching and combining arrays and interleaved to produce an OTDM signal. The integrated optical delay switching and combining arrays are adapted to be controllably set to various delays to facilitate interleaving of many possible bit-rates. Such an approach alleviates stability problems offered by conventional fiber-based OTDM technology, increases flexibility, aids in reducing the size, complexity, and cost. Furthermore, the OTDM chip of the present invention offers fine tuning capabilities thereby allowing for slight adjustments in the interleaving of optical signal streams if needed. The present invention also provides for the integration of an optical pulse source chip and a multiple-rate OTDM chip onto a single substrate or platform using hybrid packaging technology.

Abstract: A method and an apparatus is provided for introducing tunable second order polarization mode dispersion compensation to an optical signal without introducing any first order polarization mode dispersion into the optical signal. A method and an apparatus is also provided for tunable chromatic dispersion compensation by rotating the polarization state of an input signal to match the chromatic like second order PMD compensation provided by the present invention. In one configuration, birefringent elements are arranged into at least two stages, each stage having at least two birefringent elements, each birefringent element of one stage oriented orthogonal to a corresponding birefringent element of a corresponding stage. In another configuration, the polarization of optical signals emerging from each birefringent element are rotated to create effective orthogonal orientations between corresponding birefringent elements of corresponding stages.

Abstract: A method and an apparatus for implementing carrier suppressed data format on conventional OTDM modules is provided. Adaptive phase shifting of optical signals traversing one of the tributaries of an OTDM module is performed with feedback loop control. A tapped portion of the input carrier signal is phase modulated at a frequency fc, and is combined with a tapped portion of the output from the OTDM. A phase shifter controller fed with this combined signal photodetects and band-pass filters the signal around fc to extract the amplitude of the AC component of the envelope of the combined signal, which depends upon the phase difference between successive pulses of the OTDM output. This signal is used to control a phase shifter coupled along one of the tributaries of the OTDM to adjust the phase difference of the signals of the two tributaries so that carrier suppression results.

Abstract: A multi-purpose bit error rate tester (MPBERT) and a method of bit error rate (BER) testing of electrical and optical components and subsystems of electrical and optical communications systems is provided. The invention provides for bit error rate testing both in the optical and the electrical domain, and for bit error rate testing at higher than achievable rates in the electrical domain by multiplexing and demultiplexing in the optical domain. An MPBERT constructed according to the invention incorporates at least one optical multiplexer, and advantageously incorporates at least one optical demultiplexer, and in some embodiments uses high data rate optical RZ to NRZ conversion and high data rate optical NRZ to RZ conversion.

Abstract: A novel optical time division multiplexing (OTDM) module based on hybrid-integrated optical chips is disclosed. An integrated modulator chip generates optical RZ signal streams which are then interleaved in an integrated time-delay chip to produce an OTDM signal. The integrated modulator chip is coupled and secured to the integrated time-delay chip via a suitable optical index-matching layer or collimating lenses. Such an approach alleviates the stability problems offered by conventional fiber-based OTDM technology and aids in reducing the size and complexity as well as lowering the cost for the assembly. Furthermore, the time-delay chip of the present invention offers fine tuning capabilities thereby allowing for slight adjustments in the interleaving of optical signal streams when non-standard data transmission rates are required.