Optical transmitter and a method for generating light pulses with variable intensity and variable phase without an optical modulator

An optical source comprising:

• a phase randomised light source, the phase randomised light source further comprising:
• a master light source configured to intermittently generate master light pulses, wherein a phase of each generated master light pulse has a random relationship with a phase of each subsequently generated master light pulse, and wherein a first control signal is applicable to the master light source such that the master light source intermittently generates master light pulses;
• wherein the first control signal comprises a first and a second modulation feature in a period of time that one master light pulse is generated, wherein each phase modulation feature comprises a perturbation in the first control signal applied to the master light source;
• a slave light source, wherein the slave light source is optically coupled to the master light source and is configured to receive the master light pulses, and wherein a second control signal is applicable to the slave light source to cause the slave light source to generate a sequence of slave light pulses during each period of time that a master light pulse is received, such that the phase of a light pulse from the sequence has a random relationship to the phase of a light pulse from a subsequent sequence, and
• wherein each sequence comprises a first, second and third slave light pulse that are temporally separated from one another by a first time interval and wherein phase differences between the first, second and third slave light pulses depend on the phase modulation features;
• and
• an interferometer, wherein the interferometer is optically coupled to the slave light source and is configured to receive the sequences of slave light pulses, and wherein the interferometer comprises an interference component and a delay element, the delay element being configured to delay the received sequences of slave light pulses by the first time interval to form delayed sequences of slave light pulses, and
• wherein the interferometer is further configured to:
• interfere the received sequences of slave light pulses with the delayed sequences of slave light pulses at the interference component, such that pulses from a received sequence interfere with adjacent pulses of the delayed sequence;
• and
• output interfered pulses, wherein the interfered pulses comprise a first and a second output pulse that have a first and second predetermined amplitude respectively and a predetermined relative phase between them.