Abstract: A narrow linewidth semiconductor laser device has a semiconductor laser and a low noise current source operatively connected to the laser with the current source being adapted to prevent degradation of the laser's frequency noise spectrum. An optical frequency discriminator provides an error signal representative of the laser's optical frequency and a control circuit has a feedback network that provides a frequency feedback signal that is adapted to the frequency noise spectrum of the frequency discriminator and to the laser's frequency noise spectrum and tuning response. The control circuit also has a sequencer to automatically enable frequency locking of the laser on the frequency reference of the optical frequency discriminator. An enclosure encloses the frequency discriminator to isolate the frequency discriminator from external perturbations.

Abstract: There is provided a narrow linewidth semiconductor laser device comprising a semiconductor laser and a low noise current source operatively connected to the laser for supplying current thereto, the current source being particularly adapted to prevent a significant degradation of the frequency noise spectrum of the laser. The laser device also has an optical frequency discriminator providing an error signal representative of the optical frequency of the laser. The laser device also has control means having a feedback network for providing a frequency feedback signal. The feedback network is particularly adapted to the frequency noise spectrum of the frequency discriminator, the frequency noise spectrum of the laser and the tuning response of the laser. The control means is also provided with sequencing means for allowing to automatically enable frequency locking of the laser on the frequency reference of the optical frequency discriminator.

Abstract: A metallic gas cell including a metallic casing having an input open end and an output open end, and a opening located therebetween. The metallic gas cell also includes an input and an output optical modules, each being respectively hermetically attached to one of the corresponding open ends. The metallic gas cell includes sealing means for sealing each of the optical modules in one of the corresponding open ends, thereby defining an airtight cavity in the casing when the opening is sealed. The metallic gas cell also includes an optical energy absorbing gas being enclosed within the cavity. The metallic gas cell is advantageously modular for allowing the use of various input or output modules such as windows, lenses, lasers, photodetectors, and fiber collimators. The gas cell also allow multi-cavity gas cell that that use a minimum number of components and cells to be obtained. Moreover, by its specific construction, the present gas cell prevents alignment issues.

Abstract: There is provided a complex frequency response filter providing a frequency response having a desired shape. A first complex frequency response filter includes a first and a second reflecting surfaces defining a resonant cavity therebetween. Each of the reflecting surfaces respectively has a predetermined surface finish providing a given reflectivity, therefore providing resonances with a predetermined shaped frequency response of a predetermined amplitude and of a predetermined periodicity. Those frequency responses can then be summed to generate an arbitrarily complex spectral response. In another embodiment, the complex frequency response filter includes a transmission medium and a first and a second reflecting surfaces defining a resonant cavity therebetween.

Abstract: A method and a system for filtering a user light beam using a periodic filter having a frequency response stabilized at an absolutely calibrated value are provided. A primary light beam is generated by a tunable laser source and portions thereof are filtered by an absolute reference filter and the periodic filter. First the frequency of the laser source is automatically locked on the absolute reference filter, and then the frequency response of the periodic filter is locked relative to the frequency of the laser source. The frequency response of the periodic filter is therefore continuously maintained at the proper calibration. User input and output are provided to pass the user light beam through the stabilized periodic filter independently of the filter stabilization process. A broadband absolutely calibrated optical source and a method for absolutely calibrating an optical spectrum analysis device are also provided.

Abstract: There is provided a complex frequency response filter providing a frequency response having a desired shape. A first complex frequency response filter includes a first and a second reflecting surfaces defining a resonant cavity therebetween. Each of the reflecting surfaces respectively has a predetermined surface finish providing a given reflectivity, therefore providing resonances with a predetermined shaped frequency response of a predetermined amplitude and of a predetermined periodicity. Those frequency responses can then be summed to generate an arbitrarily complex spectral response.

Abstract: A metallic gas cell including a metallic casing having an input open end and an output open end, and a opening located therebetween. The metallic gas cell also includes an input and an output optical modules, each being respectively hermetically attached to one of the corresponding open ends. The metallic gas cell includes sealing means for sealing each of the optical modules in one of the corresponding open ends, thereby defining an airtight cavity in the casing when the opening is sealed. The metallic gas cell also includes an optical energy absorbing gas being enclosed within the cavity. The metallic gas cell is advantageously modular for allowing the use of various input or output modules such as windows, lenses, lasers, photodetectors, and fiber collimators. The gas cell also allow multi-cavity gas cell that that use a minimum number of components and cells to be obtained. Moreover, by its specific construction, the present gas cell prevents alignment issues.

Abstract: A method and a system for filtering a user light beam using a periodic filter having a frequency response stabilized at an absolutely calibrated value are provided. A primary light beam having a tunable frequency is generated by a tunable laser source, and then split into first and second beams respectively sent to an absolute reference filter and the periodic filter. The signal from the absolute reference filter is first used for automatically locking the frequency of the tunable laser source relative to a selected absorption features of the absolute reference filter. Once the laser source is locked, the frequency response of the periodic filter is stabilized using the filtered second beam, with a selected spectral feature of the periodic filter frequency response being locked relative to the frequency of the tunable laser source. The frequency response of periodic filter is therefore continuously maintained at the proper calibration.