Doped fiber amplifier having pass-through pump laser with integrated optical isolator

A method used with signal light having a signal wavelength, the method comprising:

• receiving the signal light at an optical isolator integrated in a package of a laser diode;
• passing the signal light from the optical isolator to an input facet of the laser diode;
• passing the signal light from the input facet through the laser diode to an output facet;
• generating pump light in an active section of the laser diode by injecting an electrical drive signal into the active section of the laser diode, the pump light having a pump wavelength different from the signal wavelength;
• transmitting the signal light and at least a portion of the pump light to a doped fiber amplifier in optical communication with the laser diode;
• and
• amplifying the signal light by interacting the pump light with the doped fiber amplifier;
• and
• wherein injecting the electrical drive signal into the active section comprises:
• injecting a first of the electrical drive signal into a first portion of the active section;
• injecting a second of the electrical drive signal into a second portion of the active section;
• and
• optically isolating at least a portion of the pump light generated with one of the first and second portions of the active section from the other of the first and second portions of the active section by a reflective structure.

A fiber amplifier operable with an electrical drive signal for amplifying signal light having a signal wavelength, the fiber amplifier comprising:

• a laser diode having an active section and having an input facet and an output facet arranged in a package of the laser diode, the input and output facets in optical communication with the signal light and configured to pass the signal light through the laser diode from the input facet to the output facet, the active section being configured to generate pump light;
• an optical isolator integrated within the package of the laser diode;
• an output fiber doped with an active dopant, the output fiber being in optical communication with the signal light and being in optical communication with at least a portion of the pump light from the laser diode;
• and
• at least one fiber Bragg grating (FBG) configured to lock the pump light from at least one of the input and output facets to the pump wavelength.

A fiber amplifier operable with an electrical drive signal for amplifying signal light having a signal wavelength, the fiber amplifier comprising:

• a laser diode having an active section and having an input facet and an output facet arranged in a package of the laser diode, the input and output facets in optical communication with the signal light and configured to pass the signal light through the laser diode from the input facet to the output facet, the active section being configured to generate pump light;
• an optical isolator integrated within the package of the laser diode;
• and
• an output fiber doped with an active dopant, the output fiber being in optical communication with the signal light and being in optical communication with at least a portion of the pump light from the laser diode;
• wherein:
• the active section comprises a waveguide extending between the input and output facets;
• a first portion of the waveguide near the input facet has a first transmissivity at least at the pump wavelength;
• a second portion of the waveguide near the output facet has a second transmissivity at least at the pump wavelength;
• and
• the first transmissivity is different from the second transmissivity.