US 7,009,716 B2Granted

System for monitoring optical output/wavelength

AssigneeElectronics and Telecommunications Research Institute

InventorsJong-Deog Kim, Byung-Seok Choi, Jong-Hyun Lee, Hogyeong Yun, Kwang-Seong Choi, Jong-Tae Moon

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Abstract

A system for monitoring an optical output/wavelength is employed to be used for a WDM system having a narrow channel space by structuring an etalon and photodiode as an integrated structure. The system includes: a laser source control unit for controlling the laser source; an optical/wavelength monitoring unit for monitoring an optical output/wavelength of the controlled laser source; a TEC control unit for controlling a TEC in order to constantly maintain the laser source of the optical output/wavelength monitoring unit to have a predetermined temperature; a temperature control unit for controlling a heater and a thermistor to set an etalon to a predetermined temperature, wherein the heater is attached on the optical output/wavelength monitoring unit and the thermistor is attached on the heater; a comparison unit for comparing the optical output signal and the wavelength signal, each of which is monitored by the optical output/wavelength monitoring unit; and a processing unit for comparing values of the compared signals with a preset value to control an input current or a temperature of the laser source.

Claims18

Dependent claims

A system for monitoring an optical output/wavelength of a light beam emitted from a laser source, comprising:

a laser source control means for controlling the laser source, wherein the light beam travels along a propagation path with a divergence angle with respect to an optical axis;
an optical output monitoring unit located within the divergence angle of the light beam for receiving a portion of the light beam and for sensing an intensity of the light beam at a predetermined location for receiving predetermined portions of the light beam, thereby obtaining an optical output signal;
a filtering unit for filtering the light beam;
an optical wavelength monitoring unit located within the divergence angle of the light beam for receiving the other portion of the light beam not shielded by the optical output monitoring unit and for sensing the wavelength generated from the filtering unit, thereby obtaining a wavelength signal;
a thermo-electric cooler (TEC) control means for controlling a TEC in order to constantly maintain the laser source to have a predetermined temperature;
a temperature control means for controlling a heater and a thermistor to set an etalon to a predetermined temperature independently on the maintained temperature of laser source by the TEC, wherein the heater is attached on the filtering unit on the air gap space on the TEC and the thermistor is attached on the heater;
a comparison means for comparing the optical output signal and the wavelength signal;
and
a processing means for comparing values of the compared signals with a preset value to control an input current or a temperature of the laser source.

6 more elements

An apparatus for monitoring an optical output/wavelength, comprising:

a laser source for generating a laser beam according to a control signal outputted from a laser source control means;
a collimation means for adjusting a divergence angle of the laser beam outputted from the laser source;
an optical output monitoring means located within the divergence angle of the laser beam for receiving a portion of the laser beam and for sensing an intensity of the laser beam outputted from the collimation means at a predetermined location for receiving predetermined portions of the laser beam, thereby obtaining an optical output signal;
a filtering means for filtering the laser beam outputted from the collimation means;
an optical wavelength monitoring means located within the divergence angle of the laser beam for receiving the other portion of the laser beam not shielded by the optical output monitoring unit and for sensing the wavelength generated from the filtering means, thereby obtaining a wavelength signal;
a first mounting means for mounting the optical output monitoring means;
a second mounting means for mounting the optical wavelength monitoring means;
an alignment means for aligning the optical output monitoring means, the filtering means, the optical wavelength monitoring means, the first mounting means and the second mounting means and for minimizing a heat conducted from a heater to the optical output monitoring means, the filtering means, the optical wavelength monitoring means, the first mounting means and the second mounting means in sequence, the alignment means having pattern to process an electric signal;
a heating means for changing a temperature of the filtering means and being disposed below a bridge-shaped structure to minimize a path of a heat conduction between the heating means and an exterior;
and
a temperature sensing means for sensing a temperature of the heating means, to thereby control the temperature of the filtering means.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/802,095Filed 15 Mar 2004
Priority: KR 10-2003-005902626 Aug 2003
Published: US 2005/0046868 A13 Mar 2005
Granted: 7 Mar 2006
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

H01S 5/0612
By varying physical parameters other than the potential of the electrodes, e.g. by an electric or magnetic field, mechanical deformation,…:…
H01S 5/0683
Stabilisation of laser output parameters: by monitoring the optical output parameters
H01S 5/0687
By monitoring the optical output parameters: stabilising the frequency of the laser
H01S
Devices using the process of light amplification by stimulated emission of radiation