Abstract: Highly advantageous spectrometer systems and associated methods are disclosed which utilize phase modulation in conjunction with first and second harmonic detection to reduce or eliminate negative impacts from interference patterns.

Abstract: A highly advantageous terahertz spectrometer with phase modulation and associated method are disclosed which utilize a second harmonic for generating an error signal to control a phase modulator to at least reduce nulls of an interference pattern.

Abstract: An adapted semiconductor laser package that may convert a first type of package pin-out arrangement to a desired pin-out arrangement. The laser package may include a laser package including a laser, an isolator, a lens, a fiber sleeve, and a pin-out arrangement. The isolator and the fiber sleeve may be jointly arranged away from the laser. The laser package may also include an adapter with a first section with a plurality of holes geometrically arranged and mated with the package pin-out arrangement, a second section with an adapter pin-out arrangement with two rows of pins extending along opposite sides of the package, and electrical connections between the plurality of holes and the pins.

Abstract: An apparatus for analyzing, identifying or imaging a target including an integrated dual laser module coupled to a pair of photoconductive switches to produce CW signals in the range of frequencies from 100 GHz to over 2 THz focused on and transmitted through or reflected from the target; and a detector for acquiring spectral information from signals received from the target and using a multi-spectral homodyne process to generate an electrical signal representative of some characteristics of the target with resolution less than 250 MHz. The photoconductive switches are activated by laser beams from the dual laser module. The lasers in the module are tuned to different frequencies and have two distinct low frequency identification tones respectively that are used in conjunction with a stable optical filter element to permit precise determination of the offset frequency of the lasers.

Abstract: An apparatus for analyzing, identifying or imaging an target including an integrated dual laser module coupled to a pair of photoconductive switches to produce cw signals in the range of frequencies from 100 GHz to over 2 THz focused on and transmitted through or reflected from the target; and a detector for acquiring spectral information from signals received from the target and using a multi-spectral homodyne process to generate an electrical signal representative of some characteristics of the target with resolution less than 250 MHz. The photoconductive switches are activated by laser beams from the dual laser module. The lasers in the module are tuned to different frequencies and have two distinct low frequency identification tones respectively that are used in conjunction with a stable optical filter element to permit precise determination of the offset frequency of the lasers.

Abstract: An adapted semiconductor laser package that may convert a first type of package pin-out arrangement to a desired pin-out arrangement. The laser package may include a laser package including a laser, an isolator, a lens, a fiber sleeve, and a pin-out arrangement. The isolator and the fiber sleeve may be jointly arranged away from the laser. The laser package may also include an adapter with a first section with a plurality of holes geometrically arranged and mated with the package pin-out arrangement, a second section with an adapter pin-out arrangement with two rows of pins extending along opposite sides of the package, and electrical connections between the plurality of holes and the pins.

Abstract: The teachings presented herein disclose a method and apparatus for controlling the optical power of a laser in a passive optical network transmitter that outputs a modulated optical signal responsive to a modulated input signal. In one or more embodiments, such a control method comprises detecting the peak amplitude of the modulated input signal, and setting the DC bias level of the laser as a function of the detected peak amplitude. These teachings may be implemented, for example, by a laser control circuit in the transceiver module of an optical network unit (“ONU”). Such an ONU may be advantageously used in a hybrid coaxial cable-optical fiber network, such as used in DPONs which interface cable system subscriber equipment to cable system head-end equipment.

Abstract: A laser module including a first housing which encloses a semiconductor laser device, a support, a fiber sleeve for holding an optical fiber, a lens, and an isolator. The isolator and the fiber sleeve are jointly arranged within a second housing which is an integral holder holding both the isolator and the fiber sleeve.

Abstract: An optical receiver having a photodetector coupled to an external optical fiber for receiving an optical communications signal and converting it into an electrical signal; an RF amplifier coupled to the electrical output of the photodetector and generating an output signal with distortion; and a post-distortion circuit connected to the output of the RF amplifier for canceling the distortion in the output signal produced by the RF amplifier.

Abstract: At least two innovations are used to overcome the limitations of conventional transimpedance or high impedance optical receiver front end amplifiers. The innovations are a) multiple stage equalization of a high-feedback resistor, low-gain transimpedance amplifier to obtain high sensitivity, and b) range switching of feedback resistors and equalization capacitors to obtain high overload. With these approaches, it is possible to design an optical receiver operating at the intrinsic limits of available device technology.

Abstract: A transversal equalizer is realized by employing variable gain and delay in the amplification branches of a traveling wave amplifier. Specifically, by adjusting the gain and delay in each branch, the traveling wave type transversal equalizer may be adjusted to having a complementary frequency response in order to compensate for linear channel gain and phase ripples. This approach permits the transversal equalizer to be designed without the use of resistive splitter and combiner networks and, therefore, without the use of high gain amplifiers. Without such amplifiers, splitters and combiners, the smaller physical size, which is afforded thereby, allows the transversal equalizer to be easily assembled as a hybrid integrated circuit.

Abstract: A lightwave receiver, suitable for CATV applications, includes an input photodiode that is capacitively coupled to the differential inputs of a balanced amplifier. Biasing of the photodiode may be achieved by connecting the photodiode in series between a pair of resistors, with the differential inputs being taken from either side of the photodiode. This arrangement avoids the use of a transformer, which exhibits considerable high frequency loss, thereby avoiding the bandwidth limitation inherent with a transformer.

Abstract: An optical homodyne receiver is realized by employing two separate signal amplification paths in a balanced receiver configuration. Specifically, the relative phase difference between a received optical signal and a local oscillator signal is extracted from nodes which, from the point of view of an amplifier extracting a data component signal, are at ac ground. This approach permits a phase detector amplifier, which extracts the relative phase component, to be dc coupled in addition to having a higher transimpedance for lower thermal noise, and thus higher sensitivity. Additionally, by extracting the data and phase component signals at different points in a balanced receiver configuration, the data and phase amplifiers can be separately engineered for optimum performance.