Abstract:
A distortion compensation circuit with frequency detection may be used with one or more non-linear elements, such as a laser, to compensate for frequency-dependent distortion generated by the non-linear element(s), for example, in broadband multichannel RF applications. Embodiments of the distortion compensation circuit may include a frequency detector circuit that detects changes in frequency loading conditions in the distortion compensation circuit such that distortion compensation may be adjusted to compensate for distortion under different frequency loading conditions. In a multichannel RF system with multiple channel operation modes, for example, the frequency detector circuit may detect changes in the frequency loading condition as a result of changing operation modes.
Abstract:
The temperature at different locations along a multiplexed laser array may be monitored by sensing temperature at two locations within a transmitter optical subassembly (TOSA) package housing the laser array. The temperature at the two locations is used to determine a temperature tilt across the laser array. Estimated temperatures may then be determined at one or more other locations along the laser array from the temperature tilt. The estimated temperature(s) may then be used to adjust the temperature proximate the other locations, for example, for purposes of tuning lasers at those locations along the laser array to emit a desired channel wavelength. The TOSA package may be used in an optical transceiver in a wavelength division multiplexed (WDM) optical system, for example, in an optical line terminal (OLT) in a WDM passive optical network (PON).
Abstract:
An optical transceiver generally includes an injection locked (IL) laser configured to generate a transmit (Tx) optical signal for transmission over an optical network and a laser driver circuit configured to modulate the IL laser based on a Tx data signal. The Tx data signal may be provided to the optical transceiver for transmission over the optical network. The Tx data signal may include a crossing point level associated with a transition between a first signal level and a second signal level. The optical transceiver may also include a crossing point control circuit configured to apply distortion to the Tx data signal, the distortion to increase the crossing point level.
Abstract:
A compact multi-channel optical may include a multi-channel transmitter optical subassembly (TOSA), a multi-channel receiver optical subassembly (ROSA) and a circuit board configured and arranged to fit within a relatively small space. The multi-channel ROSA is spaced from the circuit board to allow circuit components to be mounted between the circuit board and the ROSA. The multi-channel ROSA may also be inverted and mounted proximate a transceiver top housing portion, for example, using an L-shaped ROSA support, to transfer heat from the ROSA to the transceiver housing portion. The optical transceiver may be used in a wavelength division multiplexed (WDM) optical system, for example, in an optical line terminal (OLT) in a WDM passive optical network (PON).
Abstract:
Individual channels of a multiplexed laser array in a multi-channel optical transmitter are monitored at an output of an optical multiplexer. The monitoring may be used to confirm proper operation of each of the channels in the multiplexed laser array and/or to perform wavelength locking on each of the channels. Monitoring at the output of the optical multiplexer avoids the use of multiple photodetectors coupled directly to multiple lasers in the multiplexed laser array. The multiplexed laser array generally includes a plurality of laser emitters optically coupled to an optical multiplexer such as an arrayed waveguide grating (AWG). An optical transmitter with a monitored multiplexed laser array may be used, for example, in an optical line terminal (OLT) in a wavelength division multiplexed (WDM) passive optical network (PON) or in any other type of WDM optical communication system capable of transmitting optical signals on multiple channel wavelengths.
Abstract:
A tunable laser with multiple in-line sections generally includes a semiconductor laser body with a plurality of in-line laser sections each configured to be driven independently to generate laser light at a wavelength within a different respective wavelength range. The wavelength of the light generated in each of the laser sections may be tuned, in response to a temperature change, to a channel wavelength within the respective wavelength range. The laser light generated in each selected one of the laser sections is emitted from a front facet of the laser body. By selectively generating light in one or more of the laser sections, one or more channel wavelengths may be selected for lasing and transmission. The tunable laser with multiple in-line sections may be used, for example, in a tunable transmitter in an optical networking unit (ONU) in a WDM passive optical network (PON) to select a transmission channel wavelength.