National Research Council of Canada

Zhenguo Lu

Philip J Poole

Jiaren Liu

Gaozhi Xiao

Chander P Grover

Zhiyi Zhang

Shoude Chang

Daniel Poitras

Chunying Song

Sylvain Raymond

Pedro Barrios

Fengguo Sun

Ping Zhao

Mohamed Rahim

Greg Pakulski

Pedro Barriors

Philip Poole

A synthesized grating is provided comprising a substrate/layer, and a plurality of alternating aperiodic non-uniform low and high index profiles on a surface of the substrate/layer defining a transmission/reflection spectrum for one of either single or multi-frequency operation of said grating in an optical cavity. A method is also provided for designing the synthesized grating, comprising determining a grating structure of given profiles through analysis of an optimized weighted sum and mapping the grating profile to said surface with the plurality of alternating non-uniform low and high index profiles. A distributed feedback laser is also provided having top, bottom and two sides, comprising a top electrode, a cladding layer disposed below the top electrode a bottom electrode, a substrate disposed above the bottom electrode, one of either an active or passive waveguide layer, a synthesized aperiodic grating layer providing distributed mirrors, and wherein the waveguide layer and synthesized aperiodic grating layer are disposed between said the substrate and cladding layer and are separated by a spacer layer.

Synthesized aperiodic gratings and method of manufacture

A technique for narrowing a linewidth of a plurality of lines of a coherent comb laser (CCL) concurrently comprises providing a mode-locked semiconductor coherent comb laser (CCL) adapted to output of at least 4 mode-locked lines; tapping a fraction of a power from the CCL from the laser cavity to form a tapped beam; propagating the tapped beam to an attenuator to produce an attenuated beam; and reinserting the attenuated beam into the laser cavity, where the reinserted beam has a power less than 10% of a power of the tapped beam. The reinsertion allows the CCL to be operated to output the mode-locked lines, each with a linewidth of less than 80% of the original linewidth. By propagating the tapped and attenuated beams on a solid waveguide, and ensuring that the secondary cavity is polarization maintaining, improved stability of the linewidth narrowing is ensured.

Stable linewidth narrowing of a coherent comb laser

A multi-band (multi-color) multiwavelength mode locked laser diode is provided by dynamic phase compensation of a quantum dot active medium. The laser diode is provided with a PIN diode structure where the active medium consists of a plurality of layers of quantum dots such as those produced by self-assembly from known chemical beam epitaxy methods. The multiplicity of bands may be produced by AC Stark splitting, frequency selective attenuation, or by the inclusion of multiple different layers having different, respective, peak ASE emissions. Dispersion compensation within laser facets, waveguides, and the optically active media permit the selection of a fixed dispersion within the cavity. A dynamic group phase change induced by the AC Stark effect permits compensation of the fixed dispersion sufficiently to produce an intraband mode-locked laser. Even interband mode locking was observed.

Multi-band multiwavelength quantum dot mode-locked lasers

Methods and devices for providing a multiwavelength laser which may be used for multicasting and other optical communications uses. The present invention provides a quantum dot based multiwavelength laser with a monolithic gain block. The Fabry-Perot gain block has both upper and lower InP cladding layers. The laser system has a middle quantum dot layer with multiple stacked layers of InAs quantum dots embedded in InGaAsP. When provided with a CW injection current, the laser system produces an output spectra with equally spaced multiple emission peaks. With an input optical data signal applied to the laser system, the laser system duplicates the data in the input signal across multiple different wavelengths.

Quantum dot based semiconductor waveguide devices

A compact interrogator for the simultaneous interrogation of multi wavelength-modulated fiber optical sensors, includes a planar waveguide based demultiplexer receiving input signals from the sensors. An array of detectors is coupled to output waveguides of the demultiplexer corresponding to different nominal wavelengths. A tuning element matches the nominal wavelengths of the output waveguide to the input signals from the respective sensors to find the wavelengths of the individual sensors to be interrogated.

Simultaneous interrogation of multi wavelength-modulated fiber optical sensors by modulating an arrayed waveguide grating based demultiplexer

Polarization-mode dispersion (PMD) of an optical device, i.e. fiber or component is effected by launching a first pump laser beam of a fixed wavelength, a probe laser beam with a second fixed wavelength and a second pump laser beam having a variable wavelength and a polarization direction orthogonal to the other two beams into an optical device to generate three output signals which are input into a semiconductor optical amplifier to generate four-wave mixing (FWM) products. The average PMD of the device is computed by measuring the power of the FWM products versus the wavelength of the second pump laser beam.

Method and apparatus for measuring polarization-mode dispersion

An integrated optical dynamic channel equalizer that can be employed to equalize the channel gain level in a WDM transmission line and monitor the optical channel performance. The device consists of a circulator, a dynamic gain equalizer chip and a controller. Due to the simplicity of the dynamic gain equalizer chip, which includes one 1&#xd7;n multiplexer/demultiplexer, an n-channel variable optical attenuator array (VOA-n), a partially transparent dielectric reflective means and an n-channel detector array, the device is very compact and can be fabricated at low cost. By placing a quarter wave plate between the n-channel variable optical attenuator array and the partially transparent reflective means in the dynamic channel equalizer chip, the device can be rendered polarization insensitive.

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Ottawa, Canada

Zhenguo Lu