US5305336A — Compact optical pulse source

Claim 1

Independent Claim 141 words

Apparatus comprising: a) a semiconductor diode laser having a back facet and opposing the back facet at least one output facet through which electromagnetic radiation is emitted; b) optical waveguide means situated adjacent and external to the laser, the waveguide means including a distributed Bragg reflector, to be referred to as a "DBR", situated a given length from the output facet such that an optical cavity is defined between the back facet and the DBR with respect to the emitted electromagnetic radiation; and c) means for applying a modulated drive current to the laser at an appropriate modulation frequency for actively mode-locking the laser such that optical pulses having approximately a given wavelength are emitted from the laser; characterized in that d) the waveguiding means comprise a first optical fiber having an end proximal and optically coupled to the output facet.

Claim 2

Dependent Claim 141 words

Apparatus comprising: a) a semiconductor diode laser having a back facet and opposing the back facet at least one output facet through which electromagnetic radiation is emitted; b) optical waveguide means situated adjacent and external to the laser, the waveguide means including a distributed Bragg reflector, to be referred to as a "DBR", situated a given length from the output facet such that an optical cavity is defined between the back facet and the DBR with respect to the emitted electromagnetic radiation; and c) means for applying a modulated drive current to the laser at an appropriate modulation frequency for actively mode-locking the laser such that optical pulses having approximately a given wavelength are emitted from the laser; characterized in that d) the waveguiding means comprise a first optical fiber having an end proximal and optically coupled to the output facet.

Claim 3

Dependent Claim 121 words

Apparatus of claim 1, wherein: the first optical fiber has a core and an end distal the output facet; the DBR comprises a pattern of refractive index modulations formed in at least the core of the first optical fiber at a location intermediate the proximal and distal fiber ends such that a proximal fiber portion is defined between the proximal end and the DB R and a distal fiber portion is defined between the DBR and the distal fiber end; a substantial portion of the optical cavity lies within the proximal fiber portion; and the DBR is partially transmissive at least at the given wavelength such that a portion of the emitted electromagnetic radiation is transmitted into the distal fiber portion.

Claim 4

Dependent Claim 119 words

Apparatus of claim 1, wherein: the waveguiding means comprise a planar waveguide having a core which comprises phosphorus-doped silica, said waveguide having an end proximal the output facet and at least one end distal the output facet; the DBR comprises a series of modulations of the thickness of the waveguide; the first optical fiber is situated intermediate the output facet and the proximal film end such that the proximal film end is optically coupled to the output facet via the first optical fiber; and the DBR is partially transmissive at least at the given wavelength, such that electromagnetic radiation can be extracted from the waveguide into a second optical fiber having an end situated adjacent the distal waveguide end.

Claim 5

Dependent Claim 16 words

Apparatus of claim 1, wherein the proximal end of the first optical fiber comprises lens means.

Claim 6

Dependent Claim 51 words

Apparatus of claim 1, wherein a time-bandwidth product is associated with the optical pulses, the time-bandwidth product has a theoretical lower limit, to be referred to as the "transform-limited value", and the DBR has a bandwidth adapted such that the time-bandwidth product is less than about three times the transform-limited value.

Claim 7

Dependent Claim 51 words

Apparatus of claim 1, wherein a time-bandwidth product is associated with the optical pulses, the time-bandwidth product has a theoretical lower limit, to be referred to as the "transform-limited value", and the DBR has a bandwidth adapted such that the time-bandwidth product is less than about 1.2 times the transform-limited value.

Claim 8

Dependent Claim 42 words

Apparatus of claim 2, wherein the DBR has a wavelength of maximum reflectivity, to be referred to as the "DBR wavelength"; and the apparatus further comprises means for varying the optical length of the DBR such that the DBR wavelength is varied.

Claim 9

Dependent Claim 33 words

Apparatus of claim 7, further comprising means for varying the length of the proximal fiber portion such that the cavity length can be varied independently of variations in the length of the DBR.

Claim 10

Dependent Claim 22 words

Apparatus of claim 1, wherein the DBR is quasiperiodic and has a local period that changes with position along the optical fiber.

Claim 11

Dependent Claim 16 words

Apparatus of claim 9, wherein the local period changes monotonically with position along the optical fiber.

Claim 12

Dependent Claim 17 words

Apparatus of claim 10, wherein the local fiber changes approximately linearly with position along the optical fiber.

Claim 13

Dependent Claim 135 words

Apparatus comprising: a) a semiconductor diode laser having a back facet and, opposing the back facet, at least one output facet through which electromagnetic radiation is emitted; b) an optical fiber situated adjacent and external to the laser and having an end proximal and optically coupled to the output facet, the optical fiber including a distributed Bragg reflector, to be referred to as a "DBR", situated a given length from the output facet such that an optical cavity is defined between the back facet and the DBR with respect to the emitted electromagnetic radiation; and c) means for applying a drive current to the laser such that the laser has continuous optical output, characterized in that d) the DBR is quasiperiodic and has a local period that changes monotonically with position along the optical fiber.

Claim 14

Dependent Claim 135 words

Apparatus comprising: a) a semiconductor diode laser having a back facet and, opposing the back facet, at least one output facet through which electromagnetic radiation is emitted; b) an optical fiber situated adjacent and external to the laser and having an end proximal and optically coupled to the output facet, the optical fiber including a distributed Bragg reflector, to be referred to as a "DBR", situated a given length from the output facet such that an optical cavity is defined between the back facet and the DBR with respect to the emitted electromagnetic radiation; and c) means for applying a drive current to the laser such that the laser has continuous optical output, characterized in that d) the DBR is quasiperiodic and has a local period that changes monotonically with position along the optical fiber.

Claim 15

Dependent Claim 17 words

Apparatus of claim 12, wherein the local period changes approximately linearly with position along the optical fiber.

Claim 16

Dependent Claim 26 words

Apparatus of claim 12, wherein the local period changes such that continuous operation of the laser is substantially confined to one mode of the optical cavity.

Claim 17

Dependent Claim 29 words

Apparatus of claim 12, wherein the local period changes such that mode-beating noise is substantially eliminated from the optical output of the laser during continuous operation of the laser.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1997-04-18	1997-10-18	1998-04-19	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2001-04-18	2001-10-18	2002-04-19	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2005-04-18	2005-10-18	2006-04-19	$7700.00	Window Closed / Lapsed

Compact optical pulse source

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