Wdm comb source based optical link with improved optical amplification

Patent metadata

Field	Value
Publication number	US-2018054257-A1
Application number	US-201515560751-A
Country	US
Kind code	A1
Filing date	Mar 26, 2015
Priority date	Mar 26, 2015
Publication date	Feb 22, 2018
Grant date	—

Abstract

A transmitter (TX) for a WDM optical link includes a light source (CS) generating a plurality of discrete lines (EL) with different frequencies (f), a plurality of modulators (FSM, RRM, MZM), each modulator (FSM, RRM, MZM) being configured to modulate one of the discrete lines (EL) according to a data stream (c 1 -c 4 ), at least one optical amplifier (SOA) configured to simultaneously amplify multiple lines (EL), wherein only a subset of the generated lines (EL) is routed to the optical amplifier (SOA) resp. to each one of the optical amplifiers (SOA). A receiver (RX) for an optical link adapted to work together with the transmitter (TX) is also described. An optical link including the transmitter (TX) and/or the receiver (RX), and a method to operate said link are also described.

First claim

1 - 24 . (canceled)

25 . A transmitter for an optical link, comprising a light source generating a plurality of discrete lines with different frequencies routed to a common input bus waveguide, further comprising a plurality of frequency selective modulators, each frequency selective modulator having an input port, a through port, an add port and a drop port and being configured to:
modulate at least one of the discrete lines provided on the input port according to a data stream, output the modulated line on the drop port, pass all other light frequencies from the input port to the through port, and pass all other light frequencies from the add port to the drop port, wherein the transmitter further comprises at least one drop bus waveguide and at least one optical amplifier configured to simultaneously amplify multiple lines, wherein the light source is a comb source, the optical amplifier is a semiconductor optical amplifier, and the frequency selective modulators are arranged in a drop configuration to share the common input bus waveguide as their input bus and to share the drop bus waveguide as their drop bus, wherein the drop bus is routed to the semiconductor optical amplifier, so that only generated lines that are modulated by at least one frequency selective modulator are routed to the semiconductor optical amplifier, respectively to each one of the semiconductor optical amplifiers.

26 . The transmitter of claim 25 , wherein the plurality of frequency selective modulators comprises at least two subsets of frequency selective modulators, wherein each subset of frequency selective modulators share a common drop bus waveguide.

27 . The transmitter of claim 26 , wherein each drop bus waveguide is routed to an individual optical amplifier.

28 . The transmitter of claim 27 , wherein the outputs of at least two optical amplifiers are recombined.

29 . The transmitter of claim 28 , wherein the outputs of two optical amplifiers are recombined with an interleaver.

30 . The transmitter of claim 29 , wherein every second discrete line is referred to as an even discrete line, wherein every other discrete line is referred to as an odd discrete line, and wherein a first subset of frequency selective modulators sharing a first drop bus waveguide modulate even discrete lines and a second subset of frequency selective modulators sharing a second drop bus waveguide modulate odd discrete lines.

31 . A transmitter according to claim 25 , wherein at least one frequency selective modulator is a resonant ring modulator.

32 . The transmitter of claim 25 , wherein a frequency selective modulator comprises a modulator and a first add-drop multiplexer routing at least one discrete line from an input bus to the input of the modulator.

33 . The transmitter of claim 32 , wherein the frequency selective modulator further comprises a second add-drop multiplexer routing at least one modulated discrete line to a drop bus.

34 . An optical link, comprising a transmitter according to claim 25 .

35 . A receiver for an optical link configured to decode at least one data stream from an optical signal transmitted by a transmitter according to claim 25 , comprising a polarization splitting element with one input port and two output ports, at least one resonant add-drop multiplexer tuned to at least one line modulated according to a data stream, and at least one detector to convert a light intensity into an electrical signal, wherein light from the two output ports of the polarization splitting element is coupled into the resonant add-drop multiplexer in opposite directions, and that light is coupled from the resonant add-drop-multiplexer to the at least one detector in two opposite directions.

36 . The receiver of claim 35 , wherein optical path lengths between the polarization splitting element and the detector are substantially equal for both channel components of one and the same channel, wherein the channel corresponds to an optical carrier frequency and the channel components correspond to different polarization components.

37 . The receiver according to claim 35 , wherein multiple add-drop multiplexers are coupled to a common waveguide that forms part of an optical path between the two output ports of the polarization splitting element.

38 . The receiver according to claim 37 , wherein light from multiple add-drop multiplexers is coupled to the same detector or set of detectors.

39 . The receiver according to claim 37 , wherein the optical path between each of the output ports of the polarization splitting element and the add-drop multiplexers comprises at least one phase splitting element.

40 . An optical link comprising a receiver according to claim 35 .

41 . A method to operate an optical link, the optical link comprising a transmitter and a receiver, wherein the transmitter and/or the receiver comprises at least one parallel configuration of multiple resonant redundant add-drop multiplexers, wherein, in the case of the transmitter, the redundant add-drop multiplexers are part of a frequency selective modulator of the transmitter, the method comprising:
evaluating the minimum required power consumption to align each resonant add-drop multiplexer of the parallel configuration to a generated line with sufficient optical power to sustain an optical link; selecting a resonant add-drop multiplexer that has a lesser such power consumption than at least one other resonant add-drop multiplexer in the parallel configuration; tuning the selected resonant add-drop multiplexer to said generated line; and leaving at least one non-selected resonant add-drop multiplexer misaligned with regard to any generated line, and/or detuning at least one non-selected resonant add-drop multiplexer from a generated line.

42 . The method according to claim 41 , wherein, in the evaluation step, the minimum required power consumptions are computed for a temperature different from the ambient temperature.

43 . The method according to claim 41 , wherein, in the evaluation step, the minimum required power consumptions are computed over a temperature range in which the transmitter and/or the receiver is to be operated.

44 . The method according to claim 43 , wherein for each add-drop multiplexer, respectively for each frequency-selective modulator, the maximum value of its minimum required power consumption over said temperature range is used as a basis for the selecting step.

Assignees

• Rwth Aachen

Inventors

• Witzens Jeremy
• Merget Florian
• Mueller Juliana

Classifications

• H04B10/506 Primary

  Multiwavelength transmitters · CPC title

• H04B10/07955

  Monitoring or measuring power · CPC title

• H04B10/296

  Transient power control, e.g. due to channel add/drop or rapid fluctuations in the input power · CPC title

• H04B10/038

  using bypasses · CPC title

• H04B10/671

  for controlling the input optical signal · CPC title