An optical transmission device includes: a first drive unit that drives a VOA adjusting an attenuation amount for an optical signal from an optical amplifier; a second drive unit that drives an excitation light source of the optical amplifier; a first FF control unit that sets a first set value for the first drive unit and performs FF control; a second FF control unit that sets a second set value for the second drive unit and performs the FF control; a first control unit that controls the second drive unit in a manner that causes an optical output power from the optical amplifier to attain a first control target value; and a switch unit that switches to the first control unit when the optical output power corresponding to the second set value is attained as a result of FF control of the second FF control unit.

A burst logging system logs and transmits to a local or remote computing system event data related to errors in and or potential failures of laser system components. The system further provides for capturing data at different rates from different sensors, synchronization of data capture associated with system events and the possibility for aggregation of data from multiple systems, which can in turn be leveraged to predict and or remediate future system events.

It is difficult to construct an optical fiber transmission system enabling relay optical amplification using a coupled multi-core optical fiber as an optical transmission path; therefore, an optical amplification device includes first optical spatial layout converting means for converting a spatial layout of a plurality of optical signal beams propagating through each of a plurality of cores, from a coupled state in which optical signal beams interfere between a plurality of cores to a non-coupled state in which optical signal beam interference is reduced between a plurality of cores; optical amplifying means for amplifying, in the non-coupled state, the plurality of optical signal beams with the non-coupled state and generating a plurality of amplified optical signal beams; and second optical spatial layout converting means for converting a spatial layout of the plurality of amplified optical signal beams from the non-coupled state to the coupled state.

A distributed feedback (DFB) laser outputting a predetermined wavelength of laser light includes a quantum well active layer positioned between a p-type cladding layer and an n-type cladding layer in thickness direction. The DFB laser includes a separate confinement heterostructure layer positioned between the quantum well active layer and then-type cladding layer. The DFB laser includes an electric-field-distribution-control layer positioned between the separate confinement heterostructure layer and then-type cladding layer and configured by at least two semiconductor layers having band gap energy greater than band gap energy of a barrier layer constituting the quantum well active layer. The DFB laser has a function to select a specific wavelength by returning a specific wavelength in the wavelength-variable laser.

A smart spool is configured to be optically coupled between a pumping light source and optical point-loss sources in an optical fiber transmission line. The smart spool comprises a probe signal transmitter that transmits an optical probe signal into the transmission line. An optical detector receives probe signals scattered in the transmission line. A loss-measuring device is coupled to the optical detector and operable to measure aggregate losses in the transmission line and report the aggregate losses to a network manager. The spool comprises a fiber of sufficient length to offset the aggregated losses to enable a distributed Raman amplifier to pump the transmission line. The smart spool prevents the distributed Raman amplifier from shutting down and allows the distributed Raman amplifier to achieve entitled gain by pumping the fiber in the spool.

The present disclosure relates to a technical field of optical communication, and provides a method and an apparatus for determining maximum gain of Raman fiber amplifier. Wherein the method includes obtaining transmission performance parameters of a current optical fiber transmission line; respectively obtaining impact factors A.sub.1, A.sub.2, A.sub.4 according to a distance between a joint and a pump source, a fiber loss coefficient, and a fiber length included in the transmission performance parameters; calculating a joint loss value Att.sub.Aeff according to a distance between a joint and a pump source, a fiber loss coefficient, and looking up impact factor A.sub.3 according to Att.sub.Aeff; determining an actual maximum gain which may actually be achieved by the Raman fiber amplifier according to A.sub.1, A.sub.2, A.sub.3, A.sub.4. The actual maximum gain obtained in the present disclosure is the maximum gain that may be achieved over all input power ranges, and the original signal in system is kept to operate at a fixed gain, such that a gain locking effect is realized, and fluctuation of existing transmission signal power caused by signal change in transmission fiber link is avoided.

A laser system for generating a series of laser pulses comprising a laser generator that supplies an injection pulse to an amplifier; said amplifier comprising: a gain medium enclosed between a first mirror and a second, output, mirror opposite to said first mirror; and an optical switch set in the proximity of said first mirror; said laser system being characterized in that said amplifier is an unstable laser resonator and said injection pulse is supplied to said laser resonator in synchronism with opening of said optical switch; said series of laser pulses comprises at least one pulse having a duration shorter than or equal to 2 ns and an energy higher than 100 mJ and at least three times higher than the energy of any other pulse of said series of pulses.

An optical signal amplifier using a praseodymium doped fiber is described. The optical signal amplifier includes a signal laser, a first optical isolator, a second optical isolator a pump laser, a wave division multiplexer, a silica based glass optical fiber, a second optical isolator, an optical power meter, and an optical spectrum analyzer (OSA). The signal laser generates a signal laser beam. The pump laser generates a pumped laser beam. The wave division multiplexer combines the signal laser beam and the pumped laser beam and generates a combined laser beam. The silica based glass optical fiber has a preferred concentration of praseodymium ions of about 50?10.sup.24 ions/m.sup.3 and a length of about 5.7 m. The silica based glass optical fiber receives the combined laser beam, amplifies photons in the combined laser beam, and generates an amplified laser beam.

It is difficult to construct an optical fiber transmission system enabling relay optical amplification using a coupled multi-core optical fiber as an optical transmission path; therefore, an optical amplification device includes first optical spatial layout converting means for converting a spatial layout of a plurality of optical signal beams propagating through each of a plurality of cores, from a coupled state in which optical signal beams interfere between a plurality of cores to a non-coupled state in which optical signal beam interference is reduced between a plurality of cores; optical amplifying means for amplifying, in the non-coupled state, the plurality of optical signal beams with the non-coupled state and generating a plurality of amplified optical signal beams; and second optical spatial layout converting means for converting a spatial layout of the plurality of amplified optical signal beams from the non-coupled state to the coupled state.

The present invention relates to the technical field of optical communications, and relates to an optical amplification method and an amplifier, and in particular, to a self-adaptive wave band amplification method and an amplifier. The present invention consists of a master amplifying unit and a slave amplifying unit, and can autonomously detect the service signal wave band range of an optical transmission line, and according to the detection result, the two amplifying units do not need to perform scheduling or configuration from the level of network management, and perform direct interaction and action from the bottom layer to implement self-adaptive on, off and adjustment in real time. On one hand, power consumption is reduced, and energy is saved; and on the other hand, the performance is optimized, and an optimal optical amplification index is obtained.