Abstract: Methods for detecting and/or indicating the presence of valid data and threshold setting and data detection circuitry are disclosed. The threshold setting and data detection circuitry and related methods may be useful for fast and accurate reception of optical signals. The detection circuit generally comprises (i) a first circuit configured to regulate or control a DC offset of a differential input signal, and (ii) a second circuit coupled to the first circuit, the second circuit configured to indicate the presence of a data signal at the differential input signal when a voltage difference between true and complementary nodes of the differential input signal is above a predetermined threshold.

Abstract: Methods for receiving a signal and a detection circuit are disclosed. The detection circuit and related methods may be useful for the fast and accurate receiving of data signals. The detection circuit generally comprises a first circuit having a first time constant, a second circuit having (i) a common input with the first circuit and (ii) a second time constant, the second time constant being less than the first time constant, and a switch configured to (i) charge the first circuit with an input signal when the switch is in a first state, and (ii) charge or discharge the second circuit with the input signal when the switch is in a second state, the switch having the second state when the input signal is no longer received at the common input.

Abstract: Methods, circuits, architectures, apparatuses, and algorithms for determining a DC level in an AC or AC-coupled signal. The method generally includes disabling the AC or AC-coupled signal; sampling the disabled AC or AC-coupled signal to obtain sampled DC values of the AC or AC-coupled signal; and calculating the DC level using the sampled DC values of the AC or AC-coupled signal. The present transmitter generally includes an electro-absorption modulated laser (EML); a photodetector; a signal source configured to provide an AC or AC-coupled signal to the EML; and a microcontroller or microprocessor configured to (i) control the signal source, (ii) receive information from the photodetector, and (iii) deactivate the signal source for a predetermined length of time. The circuits, architectures, and apparatuses generally include those that embody one or more of the inventive concepts disclosed herein.

Abstract: In a coarse wavelength division multiplexing (CWDM) optical transmission system, a distributed feedback (DFB) laser is tuned so that the peak reflection of the grating overlaps with the gain range of the DFB laser. The diffraction grating is tuned so that the peak is positioned on the long wavelength end of the gain spectrum at a selected temperature. The optical transmission system operates in an environment having a wide temperature range (i.e., about ?40° C. to about 85° C.). Heat is applied to the laser and as the laser temperature increases, the gain range overtakes the grating peak. When the gain range and the grating peak overlap at increased laser temperature, laser output is improved.

Abstract: In a coarse wavelength division multiplexing (CWDM) optical transmission system, a distributed feedback (DFB) laser is tuned so that the peak reflection of the grating overlaps with the gain range of the DFB laser. The diffraction grating is tuned so that the peak is positioned on the long wavelength end of the gain spectrum at a selected temperature. The optical transmission system operates in an environment having a wide temperature range (i.e., about ?40° C. to about 85° C.). Heat is applied to the laser and as the laser temperature increases, the gain range overtakes the grating peak. When the gain range and the grating peak overlap at increased laser temperature, laser output is improved.

Abstract: A method and apparatus is presented for providing improved responsiveness of a receiver device. One embodiment includes a receiver device including an avalanche photodiode (APD), a transimpedance amplifier (TIA), and an automatic gain control (AGC) device configured to adjust the reverse bias voltage applied to the APD according to an approximate DC average of the incoming optical signal. A switch in the AGC device may be used to increase or decrease the time constant of an RC combination determining the DC averaging time period, thereby tailoring the response of the AGC device to characteristics of the incoming data pattern. The resulting receiver exhibits improved responsiveness and sensitivity by adapting to varying data patterns including those with data bursts interspersed with gaps.

Abstract: A plug-in, optical add/drop (OAD) device includes a filter for adding and dropping a light beam of wavelength (?k) from a combined light beam having individual beams of different wavelengths (?1 . . . n). Several devices can be selectively integrated to create an optical communications system that will handle “n” different optical communications circuits. In operation, the devices are individually connected (plugged-in) to a GBIC, and they are serially connected (plugged-in) to each other. Consequently, immediately upstream from a device, the combined light beam includes wavelengths (?1 through ?n). On the other hand, the combined light beam immediately downstream includes (?1 through ?k?1 and ?k+1 through ?n).

Abstract: Devices and methods for effecting and managing the bi-directional transmission of data and communications over a single optic fiber are provided. Methods and devices of the invention utilize fiber-optic transmitters and receivers made for WDM transmission, and at least two slightly different wavelengths, in the 1.5 um range. Devices and methods of the invention facilitate simultaneous bi-directional optical transmission over a long distance, while reducing or eliminating cross-talk.

Abstract: Single transceiver modules are provided at each end of a single communication link such that the need for redundant links is reduced or eliminated. Modules of the invention provide full assurance against disruption of communication due to fiber breakdown, and certain forms of equipment failure, such as the failure of a single receiver. Modules of the invention include multiple reception and transmission ports, and can be applied to any communication link, and require that redundant data be sent by two separate transceivers via two separate fibers. Devices and methods are provided which reduce, or eliminate the need for “client side 1+1 protection.

Abstract: The invention provides means and methods for combining high-speed data and analog video signals over the same optical fiber. Optical diplexers and tri-plexers are employed to combine bi-directional data transmission and uni-directional video transmission over a single optical fiber. In one aspect, optical diplexers and tri-plexers of the invention include an optical data transmitter, an optical data receiver and an optical video receiver when they are disposed to function at the receiving end of a video signal. In another aspect, optical diplexers and tri-plexers of the invention include an optical data transmitter, an optical data receiver and an optical video transmitter when they are disposed to function at the transmission end of a video signal. The invention enables the simultaneous transmission of one signal to multiple video signal receivers. Numerous combinations of different optical wavelength pairs can be used to separate data and video signals.

Abstract: A plug-in, optical add/drop (OAD) device includes a filter for adding and dropping a light beam of wavelength (&lgr;k) from a combined light beam having individual beams of different wavelengths (&lgr;1 . . . n). Several devices can be selectively integrated to create an optical communications system that will handle “n” different optical communications circuits. In operation, the devices are individually connected (plugged-in) to a GBIC, and they are serially connected (plugged-in) to each other. Consequently, immediately upstream from a device, the combined light beam includes wavelengths (&lgr;1 through &lgr;n). On the other hand, the combined light beam immediately downstream includes (&lgr;1 through &lgr;k−1 and &lgr;k+1 through &lgr;n).