Reduced noise wavelength locker module

Details Reduced noise wavelength locker module Reduced noise wavelength locker module

2001-11-28

2004-01-27

Leung, Quyen (Department: 2828)

Radiant energy

Photocells; circuits and apparatus

Optical or pre-photocell system

C356S519000, C372S032000

Reexamination Certificate

active

06683295

ABSTRACT:

FIELD OF THE INVENTION
The present invention is directed to a wavelength locker/monitor, more particularly to a wavelength locker/monitor which reduces noise.
BACKGROUND OF THE INVENTION
A wavelength locker disclosed in co-pending, commonly assigned U.S. patent application Ser. No. 09/543,760 entitled “An Etalon, a Wavelength Monitor/locker Using The Etalon and Associated Methods” filed on Apr. 5, 2000, the entire contents of which are hereby incorporated by reference for all purposes, is shown in
FIG. 1. A
wavelength locker module
1100
includes an optics block
105
, a pair of photodetectors
122
,
124
and a mount
126
for housing the photodetectors
122
,
124
. The optics block
105
includes a splitter diffractive element
110
, two reflectors
112
,
114
, and two correcting diffractive optical elements
116
,
118
. An etalon
120
may be mounted to the optics block
105
or otherwise positioned between the optics block and one of the photodetectors
122
,
124
.
The splitter diffractive element
110
receives an input beam
130
and splits two beams
132
,
134
off of the input beam
130
. A through beam
136
continues on in the optical system if the wavelength locker
100
is used to monitor light output from a front facet of a light source. Typically, the split beams
132
,
134
are the +/−1 diffractive order beams. As shown in this particular configuration, the beam
132
serves as a reference beam and the beam
134
serves as the filter beam. The reflectors
112
,
114
reflect the reference beam
132
and the filter beam
134
, respectively, to the corrector diffractive elements
116
,
118
, respectively. The reference beam
132
travels to the reference photodetector
122
. The filter beam
134
travels through the etalon
120
to the filter photodetector
124
.
The use of the reflectors to fold the reference and filter beams allows the separation of reference and filtered beams to be large enough that the detectors may be packaged in the optical system without having to manufacture diffractives with extremely small feature size and more than two phase levels. However, these reflectors also give rise to noise in the reference and filter signals, e.g., the reflected signal of the etalon in the reference side and the etalon effect due to the parallel surfaces of the optics block
105
. Further, the reflectors potentially clip the through beam
136
, reducing the power therein and adding noise.
SUMMARY OF THE INVENTION
The present invention is therefore directed to a wavelength monitor/locker which substantially overcomes one or more of the problems due to the limitations and disadvantages of the related art.
It is an object of the present invention to provide various features which aid in reducing noise in a wavelength locker. These features may be used in any combination in a wavelength locker. These features include avoiding the use of reflectors, using a diffractive splitter which outputs evanescent beams for diffractive orders greater than one, using anti-reflective coatings, using an opaque material with through holes for the light, and designing the wavelength locker to be used at a tilt.
These and other objects of the present invention will become more readily apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating the preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.


REFERENCES:
patent: 5428700 (1995-06-01), Hall
patent: 5666225 (1997-09-01), Colbourne
patent: 5784507 (1998-07-01), Holm-Kennedy et al.
patent: 5798859 (1998-08-01), Colbourne et al.
patent: 5825792 (1998-10-01), Villeneuve et al.
patent: 5828689 (1998-10-01), Epworth
patent: 6005995 (1999-12-01), Chen et al.
patent: 6061135 (2000-05-01), Levitt et al.
patent: 6373809 (2002-04-01), Rauch et al.
patent: 6385217 (2002-05-01), Singh et al.
patent: 6452146 (2002-09-01), Barchers
patent: 6560252 (2003-05-01), Colbourne et al.
patent: 6560253 (2003-05-01), Munks et al.
patent: 6567437 (2003-05-01), Imaki et al.
patent: 2003/0035119 (2003-02-01), Myatt et al.
patent: 2003/0072010 (2003-04-01), Boye
patent: 0 875 743 (1997-02-01), None
patent: 0 911 621 (1998-03-01), None
patent: WO97/05679 (1997-02-01), None
patent: WO99/04466 (1999-01-01), None
patent: WO99/18612 (1999-04-01), None

Affiliated with

Also associated with

Rating

Reduced noise wavelength locker module does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Reduced noise wavelength locker module, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Reduced noise wavelength locker module will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3234342