1. A multiwavelength laser system comprising
a multiple layer Fabry-Perot gain block comprising
a top InP cladding layer;
a middle quantum dot layer comprising a plurality of stacked layers of InAs quantum dots embedded in InGaAsP;
a bottom InP cladding layer;
wherein
said gain block has
a first laser end facet being coated with a high reflectivity coating and
a second laser end facet being coated with a partially reflective coating, said coatings having a predetermined reflectivity ratio to one another;
said gain block has a ridge waveguide structure;
said gain block has a predetermined cavity length based on a desired channel spacing between emission peaks of a multiwavelength output of said laser.
2. A laser system according to claim 1 wherein said desired channel spacing is determined according to
\u0394\u03bb(\u03bb)=\u03bb22\xb7neff(\u03bb,T,J)L
where \u0394\u03bb is the the channel spacing,
\u03bb is the vacuum wavelength,
T is the device temperature,
J is the injection current density,
L is the cavity length, and
neff(\u03bb,T,J) is a function of T, J, and L and which represents an effective refractive index.
3. A laser system according to claim 1 wherein an InGaAsP cap covers said top cladding layer.
4. A laser system according to claim 1 wherein said plurality of stacked layers of InAS quantum dots comprises at least 2 layers of self-assembled InAs quantum dots.
5. A laser system according to claim 4 wherein said plurality of stacked layers of InAs quantum dots comprises 5 stacked layers of InAs quantum dots.
6. A laser system according to claim 1 wherein said laser system is driven by CW injection currents.
7. A laser system according to claim 1 wherein said middle quantum dot layer comprises said plurality of stacked layers of self-assembled InAs quantum dots embedded in quaternary InGaAsP.
8. A laser system according to claim 1 wherein said laser system is used in a wavelength multicasting system, the wavelength multicasting system comprising
said multiwavelength laser system
input means for receiving an input data optical signal
an optical circulator for receiving said input data signal and for sending said input data signal to said multiwavelength laser system and for receiving a multiwavelength output of said multiwavelength laser system, said optical circulator being coupled to said multiwavelength laser system.
9. A method for multicasting an optical input data signal to different optical wavelengths, the method comprising :
a) receiving an input optical data signal;
b) transmitting said input optical data signal to a quantum dot based multiwavelength laser system;
c) receiving a multiple wavelength output from said quantum dot based multiwavelength laser system.
10. A method according to claim 9 wherein said quantum dot based multiwavelength laser system comprises:
a multiple layer Fabry-Perot gain block comprising
a top InP cladding layer;
a middle quantum dot layer comprising a plurality of stacked layers of InAs quantum dots embedded in InGaAsP;
a bottom InP cladding layer;
wherein
said gain block has
a first laser end facet being coated with a high reflectivity coating and
a second laser end facet being coated with a partially reflective coating, said coatings having a predetermined reflectivity ratio to one another;
said gain block has a ridge waveguide structure;
said gain block has a predetermined cavity length based on a desired channel spacing between emission peaks of a multiwavelength output of said laser system.
11. A method according to claim 10 wherein said desired channel spacing is determined according to:
\u0394\u03bb(\u03bb)=\u03bb22\xb7neff(\u03bb,T,J)*L
where \u0394\u03bb is the the channel spacing,
\u03bb is the vacuum wavelength,
T is the device temperature,
J is the injection current density,
L is the cavity length, and
neff(\u03bb,T,J) is a function of T, J, and L and which represents an effective refractive index.
12. A method according to claim 10 wherein an InGaAsP cap covers said top cladding layer.
13. A method according to claim 10 wherein said plurality of stacked layers of InAS quantum dots comprises at least 2 layers of self-assembled InAs quantum dots.
14. A method according to claim 13 wherein said plurality of stacked layers of InAs quantum dots comprises 5 stacked layers of InAs quantum dots.
15. A method according to claim 10 wherein said laser system is driven by CW injection currents.
16. A method according to claim 10 wherein said middle quantum dot layer comprises said plurality of stacked layers of self-assembled InAs quantum dots embedded in quaternary InGaAsP.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A detecting device comprising:
a plurality of detectors;
a processing device that receives and processes a detection signal from the detectors;
a plurality of cables that connect the plurality of detectors and the processing device; and
a cable clip that forms the plurality of respective cables into a flat cable so that the cables which are placed parallel to and in contact with each other are restrained from moving at desirable positions from a side of the processing device.
2. The detecting device according to claim 1, wherein
the cables are coaxial cables, and
the cable clip includes a plurality of clips, the clips being arranged so as to make the coaxial cables branch off in stages by decreasing a number of the coaxial cables to be formed into the flat cable in stages from the side of the processing device.
3. The detecting device according to claim 1, wherein a length of the cables formed into the flat cable with the cable clip on the side of the processing device is arranged to be shorter as the desirable number of the plural cables decreases.
4. The detecting device according to any one of claims 1, wherein
the detectors are antennas,
the processing device is a receiving device,
each of the antennas is arranged at a desirable position on an outside-body of a subject, and receives a radio wave transmitted from a body-insertable device, and
the coaxial cables are arranged along the outside-body of the subject.
5. A manufacturing method of a detecting device in which a plurality of detectors and a processing device which receives and processes a detection signal from the detectors are connected through a plurality of cables, comprising:
connecting the detectors and the cables respectively;
forming into a flat cable the plurality of cables to which the detectors are connected, with cable clips at predetermined intervals so that each cable clip bundles more than one cable; and
connecting a connector to ends of the plurality of bundled cables, the ends being on a side of the processing device.
6. The manufacturing method of a detecting device according to claim 5, wherein a number of the cables formed into the flat cable is decreased in stages from the side of the processing device to make the cables branch off in stages.
7. The manufacturing method of a detecting device according to claim 5, wherein the predetermined intervals are set shorter as the number of the cables decreases.