This application is related to U.S. Patent
Application No. 13/538,525 (the 525 Application) filed
on June 29, 2012 and incorporated by reference herein.
This application is further related to U.S. Patent
Application o . 13/800634 (attorney docket number 812249-
US-NP) (the 249 Application) filed on even date herewith
and incorporated by reference herein. The present
application claims the benefit to the previously filed
U.S. Provisional Patent Application No. 61/667,380 of the
same title, filed July 2 , 2012, and which is incorporated
herein by reference in its entirety. The present
application further claims the benefit to the previously
filed U.S. Provisional Patent Application No. 61/667,374
also of the same title, filed July 2 , 2012 (the 374
Application) , and which is incorporated herein by
reference in its entirety.
TECHNICAL FIELD
This application is directed, in general, to optical
communications systems and methods .
BACKGROUND
This section introduces aspects that may be helpful
to facilitating a better understanding of the inventions.
Accordingly, the statements of this section are to be
read in this light and are not to be understood as
admissions about what is in the prior art or what is not
in the prior art.
Optical switching networks employ a switching
topology that may be referred to as an "optical switch
fabric." As the size and speed of such networks grows,
new optical switch fabrics that provide greater
capability are needed to keep pace with such growth. One
aspect of capability to be addressed is configuration of
such optical networks.
SUMMARY
One aspect provides a system, e.g. a reconf igurable
electro-optical network, including first input and first
output waveguides. The input waveguide is configured to
receive a first input optical signal. The signal includes
a first modulated input wavelength channel. The output
waveguide is configured to receive a carrier signal
including an unmodulated output wavelength channel. A
first input microcavity resonator is configured to derive
a modulated electrical control signal from the modulated
input wavelength channel. A first output microcavity
resonator is configured to modulate the output wavelength
channel in response to the control signal.
Another aspect provides a method, e.g. for forming a
reconf igurable electro-optical network. The method
includes forming a first input waveguide capable of
receiving a first input optical signal, the signal
including a first modulated input wavelength channel. A
first output waveguide is formed that is capable of
receiving a carrier signal, the carrier signal including
an unmodulated output wavelength channel . A first input
microcavity resonator is formed that is configured to
derive a modulated electrical control signal from the
modulated input wavelength channel. A first output
microcavity resonator is formed that is configured to
modulate the output wavelength channel in response to the
control signal.
In some of the above embodiments the first input
microcavity resonator may be one of a plurality of input
microcavity resonators configured to derive an electrical
control signal from each one of a corresponding plurality
of modulated input wavelength channels. The first output
microcavity resonator may be one of a plurality of output
microcavity resonators each configured to modulate a
corresponding output wavelength channel in response to a
corresponding one of the control signals. A controller is
configured to reconfigure connectivity between the input
microcavity resonators and the output microcavity
resonators .
In any of the above embodiments the controller may
include a cross-connect switch having N inputs and N
outputs, and configured to provide a plurality of unique
combinations of signal paths of the control signals
between the input microcavity resonators and the output
microcavity resonators. In some such embodiments the
cross-connect switch has outputs, and includes a
plurality of sub-switches each being configured to switch
VN inputs to outputs. In some embodiments the crossconnect
switch provides N ! unique combinations of signal
paths .
In any of the above embodiments the input and output
waveguides may be located on a first substrate and the
controller may be located on a second substrate. In some
such embodiments the first and second substrates are may
both be bonded to an interposed interconnect substrate.
In any of the above-described embodiments the
microcavity resonators may comprise ring resonators. In
any of the above-described embodiments the input
wavelength channel and the output wavelength channel may
each employ a same wavelength. In any of the abovedescribed
embodiments the system may include an optical
source configured to produce the carrier signal. In such
embodiments the optical source may be configured to
produce a plurality of wavelength components in the
optical S , C , or L bands.
Another embodiment is a system comprising an NMxNM
electrical cross-connect, N first sets and N second sets.
Of the N first sets, each first set including M ring
resonators optically coupled to an optical waveguide
corresponding to the same first set, each ring resonator
of the first sets having an optical-to-electrical output
connected to a corresponding electrical input of the
NMxNM electrical cross-connect. Of the N second sets,
each second set includes M ring resonators optically
coupled to an optical waveguide corresponding to the same
second set, each ring resonator of the second sets having
an optical-to-electrical input connected to a
corresponding output of the NMxNM electrical crossconnect
.
Some such embodiments further comprise N optical
transmitters capable of transmitting on M optical
transmission channels, each transmitter optically coupled
to a corresponding one of the optical waveguides
optically coupled to one of the first sets . Some such
embodiments further comprise N optical receivers capable
of receiving on M optical reception channels, each
receiver optically coupled to a corresponding one of the
optical waveguides optically coupled to one of the second
sets. In any such embodiments, the electrical crossconnect
may be configured to connect each ring resonator
of a same one of the first sets to a different one of the
second sets. In any such embodiments, the electrical
cross-connect may be configured to connect each ring
resonator of one of the first sets to a different one of
the second sets. In any such embodiments, the electrical
cross-connect may be configured to connect each ring
resonator of one of the second sets to a different one of
the first sets. In any such embodiments, the electrical
cross-connect is configured to connect each ring
resonator of one of the second sets to a different one of
the first sets. In any such embodiments, the NMxNM
electrical cross-connect may be dynamically
reconf igurable .
BRIEF DESCRIPTION
Reference is now made to the following descriptions
taken in conjunction with the accompanying drawings, in
which :
FIG. 1 illustrates a system, e.g. a reconf igurable
electro-optical switching matrix, according to one
embodiment in which electrical data signals produced from
data-modulated optical carriers are routed by a
reconf igurable electrical switch to a plurality of output
microcavity resonators (e.g. ring resonators) to datamodulate
wavelength channels of output optical signals;
Fig. 1A is a block diagram illustrating how the
system of FIG. 1 may be used to implement an optical
communication system between N electronic devices that
transmit data-modulated optical carriers and electronic
devices, which receive data-modulated optical carriers;
FIG. 2 schematically illustrates aspects of a
wavelength comb including a number of wavelength channels
of a WDM optical signal;
FIG. 3 illustrates an optical-to-electric converter
used in various embodiments to convert an optical signal,
e.g. a binary phase-shift keyed (BPSK) optical signal, to
a corresponding electrical signal;
FIG. 4 illustrates a detail view of the system of
FIG. 1 for signal conversion and routing of one received
WDM optical signal to an input sub-switch of the
reconf igurable electrical switch;
FIG. 5 illustrates a detail view of the system of
FIG. 1 for signal routing and conversion from one output
of the reconf igurable electrical switch of FIG. 1 to
microcavity resonators configured to modulate output
optical wavelength channels;
FIGs . 6A-6C illustrate cross-sectional views of
planar structures that may be used to produce various
embodiments of components of the system of FIG. 1;
FIG. 7 presents a flow diagram of a method, e.g. for
forming a system according to various embodiments, e.g.
the system of FIG. 1 ; and
FIG. 8 presents a flow diagram of a method, e.g. for
forming a system according to various embodiments, e.g.
the system of FIG. 1 .
DETAILED DESCRIPTION
The inventors have determined that a compact and
flexible architecture for switching data between optical
WDM (wavelength-division multiplexed) channels in an
optical network may be implemented using microcavity
resonators coupled to input waveguides to convert
received data-modulated optical signal streams to
corresponding data-modulated electrical signal streams,
and electrically switching the data-modulated electrical
signal streams to a plurality of microcavity resonators,
which re-convert the individual data-modulated electrical
signals into output data-modulated optical carriers.
Some structures and/ or methods described in the 374
Application and/or the 249 Application may be suitable
for making or using similar structures and/or methods of
the present application.
FIG. 1 presents a system 100, e.g. an embodiment of
an Mx reconf igurable optical network 100 in one
nonlimiting example. The parameter M describes a number
of wavelength channels in a wavelength division
multiplexed (WDM) optical signal that may be received by
the system 100 on each of WDM modulated optical
signals. The system 100 is illustrated without limitation
with M=N=6 . Those skilled in the pertinent art will
appreciate that the principles of the disclosed
embodiments are adaptable to different values of M and N ,
and that M and N need not be equal.
The system 100 includes three sections that are
described in turn, a receiver stage 105 that which
performs optical-to-electrical conversion, an electrical
switching stage 110, and a transmitter stage 115 that
performs electrical-to-optical conversion.
The receiver stage 105 includes a plurality of input
waveguides 120-1...120-6, collectively referred to as input
waveguides 120. Each waveguide 120-1...120-6 may receive a
WDM optical signal 122-1...122-6, including a s many as M
{e.g. 6 ) data-modulated wavelength channels.
Each of the multi-channel optical signals 122 may be
coupled to the system 100 via, e.g. grating couplers. A s
appreciated by those skilled in the optical arts, a WDM
signal may be schematically described b y a frequency or
wavelength comb. FIG. 2 illustrates a representative
wavelength comb 200 that includes six wavelength channels
. . · The wavelength channel components of the comb 200
may be spaced by a WDM grid spacing Dl , e.g. a regular,
about even spacing of the wavelength components by a same
frequency difference, e.g. about 100 GHz.
The receiver stage 105 further includes a plurality
of input microcavity resonator sets 125-1...125-N (e.g.
N=6) , each including M microcavity resonators 130 (e.g.
M=6) . Each microcavity resonator 130 may be, e.g. a ring
resonator (microring) or a disk resonator (microdisk)
configured to couple to a particular wavelength channel
of an optical signal 122 propagating in an adjacent
waveguide 120. The resonant wavelength is not limited to
any particular value, and may be selected to be in any
wavelength band used in optical communications, e.g. in
the S band (1460 nm - 1530 nm) , the C band (1530 nm -
1565 nm) or the L band (1565 nm - 1625 nm) , e.g., by
adjusting the refractive index of the individual
microcavity resonator.
In the remaining discussion, the microcavity
resonators 130 are described as ring resonators without
limitation thereto. The microcavity resonator sets 125
may therefore also be referred to as ring resonators sets
125. An individual ring resonator may be designated 130-
MN", where the integers M and N are replaced by that
resonator' s assignment to a particular one of the M
wavelength channels and a particular one of the
received input signals. Moreover, an optical signal may
be described by its frequency or equivalently by its
wavelength lM. Each ring resonator set 125 is optically
coupled to a corresponding one of the input waveguides
120 .
An individual one of the ring resonators 130 in each
set 125 is configured to couple to a corresponding one of
the wavelength channels of the received multi-channel
optical signal. Each ring resonator 130 has a resonant
wavelength, which is determined in part by its optical
path length and is the wavelength at which optical power
couples resonantly from the associated input waveguide
120 to that ring resonator 130. In some or all of the
ring resonators 130 adjustment of the resonant wavelength
may be performed, e.g. by a heater, which can adjust the
effective refractive index of a corresponding one of the
ring resonators 130. Thus, e.g., the ring resonators 130-
11, 130-12...130-16 are configured to couple to the l
wavelength channel, the ring resonators 130-21, 130-
22...130-26 are configured to couple to the l2 wavelength
channel, etc.
An optical-to-electrical (OE) converter 300 is
located adjacent each ring resonator 130. One such OE
converter 300 is illustrated in FIG. 3 . The OE converter
300 includes a waveguide segment 310 and a photodiode
320 . The photodiode 320 converts optical power
propagating within the waveguide segment 310 to an
electrical signal. When a particular wavelength channel
couples to a particular ring resonator 130, the optical
power within the ring is also coupled to the associated
waveguide segment 310. Thus the OE converter 300
transfers the received optical signal to the electrical
domain. Collectively, the MxN instances of the OE
converter 300 may produce up to MxN data-modulated
electrical signals 138 (FIG. 1 ) from the received MxN
separate data-modulated optical carriers, i.e., 36 in the
present example embodiment .
Returning to FIG. 1 , the electrical switching stage
110 includes an MxN by MxN electrical cross-connect
switch 140 (e.g., a NMxNM electrical cross-connect) that
receives the MxN electrical signals at its inputs and
routes each signal to a single corresponding one of its
MxN outputs under control o f a controller 145. In
particular, the electrical cross-connect switch 140 is
configured to direct one of the converted electrical
signal streams from each OE converter set 125-1 to 125-N
to each of the electrical-to-optical (EO) converter sets
175-1 to 175-M. The mapping of the data-modulated
electrical signal streams 138 from the inputs to the
outputs o f the switch 140 may be selectively changed b y
the operation o f the controller 145 is discussed further
b elo .
The implementation o f the switch 140 is not limited
to any particular form. In the illustrated example
embodiment, the switch 140 is "square", meaning the
number of inputs is equal to the number of outputs, and
the number is a squared integer, e.g. MxN=3 6 , where
M = = . In such embodiments, the switch 140 may be
efficiently implemented using about ' input sub-switches
150-1...150-6, about l'N output sub-switches 155-1... 155-6,
and about intermediate sub- switches 160-1... 1 0- .
Alternatively and without limitation, the switch 140 may
be implemented directly as an N xN (e.g. 36x36) switch.
In some embodiments M¹N , such as when the number o f
wavelength channels of the received optical signals 122
is not equal to the number of optical signals 122
received .
FIG. 4 illustrates more specifically the connections
between one microcavity resonator set, e.g. the set 125-
1 , and the inputs of a sub-switch 150, e.g. the subswitch
150-1. The output of each OE converter 300, e.g.
one of the electrical signals 138, is connected via an
individual electrical path to a corresponding input of
the sub-switch 150-1. The illustrated embodiment is but
one possible interconnection between the OE converters
300 and the sub-switch 150-1. Because the switch 140 may
arbitrarily map inputs to outputs, the signals 138 may be
presented in any order to the switch 140.
Referring again to FIG. 1 , the transmitter stage 115
includes an optical source 162 and M optical waveguides
165, e.g. M=6 . The optical source 162 produces M
continuous wave (CW) optical signals 170-1 to 170-M
having N wavelength component channels, e.g. as
illustrated by the unmodulated frequency comb such as
described in FIG. 2 . The optical source 162 may include
various components, e.g. multi-wavelength-channel laser
sources and optical power splitters. The wavelength
component channels may have the same wavelengths as those
of the received optical signals 122, but are not limited
thereto. The waveguides 165 receive the optical signals
170 having N wavelength channels, e.g. N=6.
A corresponding microcavity resonator set 175-1 to
175-M is optically coupled to and located adjacent to a
segment of a corresponding one of the waveguides 165 and
includes N microcavity resonators 180. The resonators 180
may also be designated by M and N , e.g. 180-MN. Each
microcavity resonator 180 within each set 175 is
configured to couple to one of the wavelength channels of
the C signal 170 propagating within that waveguide 165.
Thus, for the illustrated example, one microcavity
resonator 180 in each set 175 may be configured to have a
resonant frequency at each of about f l2, l3, l l5, and
l . Some or all of the microcavity resonators may include
a tuning heater that sets the resonant optical wavelength
therein .
The resonant optical wavelength of each ring
resonator 180 is also modulated by one of MxN electrical
data-modulated electrical signal streams 142 from the
cross-connect switch 140. A subset of N of the datamodulated
signal streams 138 from one the sub-switch 155
controls a corresponding one of each of the resonator
sets 175, the corresponding ones being configured to
couple to a single one of the wavelength channels. For
example, the sub-switch 155-1 provides N signals (e.g.
N=6 in FIG. 1), each signal being configured to control
the ring resonator 180 in each set 175 that is configured
to modulate . From another viewpoint, a subset of M of
the data-modulated signal streams 142 from the switch 140
controls the ring resonators in a corresponding set 175,
the set 175 including M ring resonators 180 corresponding
to l , l , ... e.g. M=6. The remaining signals 142 from
the switch 140 are configured analogously to modulate the
remaining wavelength channels in the optical waveguides
165-1 to 165-M.
FIG. 5 illustrates more specifically the connections
between a sub-switch 155, e.g. the sub-switch 155-1, and
a row of the ring resonators 180, e.g. those
corresponding to the wavelength channels. The
respective outputs of the sub-switch 155-1 are each
routed to a single one of the ring resonators 180.
However, as before the switch 140 may arbitrarily map the
inputs to outputs, so the wavelength channel data may be
connected in any order to the ring resonators 180.
Referring again to FIG. 1 , modulation of the ring
resonators 180 may be by, e.g. electro-optic, thermal or
free-carrier modulation of the optical patch length. The
modulation data-modulates the coupled wavelength channel
of the carrier signal propagating in the corresponding
waveguide 165. Additional aspects of such modulation are
described in the 525 Application. By modulating the
resonant frequencies of each of the ring resonators 180,
the system 100 produces output optical signal streams
185. The system 100 may thereby transfer the data
received on each one of the wavelength channels of the
input signals 122 to a selected corresponding one
wavelength channel of a corresponding one of the output
signals 185.
Thus the system 100 is expected to provide a high
speed and flexible architecture for configuring an
optical switch fabric of an optical communication system.
The system 100 may be used in many types of optical
systems. In one example, the system may be used to route
optical signals within an integrated photonic optical
processor. In another example, the system 100 may provide
quasi-static or dynamic reconfiguration of optical paths
in a communication system, e.g. a long-haul optical
communication system. The system 100 may also be used to
enable machine-to-machine optical communications in a
data center .
FIG. 1A illustrates how the system 100 enables
machine-to-rnachine communications between a set of N
machines 900-1 to 900-N, which output optical datamodulated
carriers, and a set of N machines 1000-1 to
1000-N, which receive and process data-modulated optical
carriers. Each machine 900-1 to 900-N connects via a
corresponding optical fiber 120-1 to 120-N to a
corresponding microcavity resonator set 125-1 to 125-N.
Each machine 1000-1 to 1000-N connects via a
corresponding optical fiber 165-1 to 165-N to a
corresponding microcavity resonator set 175-1 to 175-N.
In the system 100, each machine 900-1 to 900-N has
an optical transmitter capable of outputting datamodulated
optical carriers in M wavelength channels.
In the system 100, each machine 1000-1 to 1000-M has
an optical receiver capable of inputting and processing
data-modulated optical carriers in M wavelength channels.
In one embodiment, the system 100 is a data center
with N digital data processors 900-1 to 900-N and N
digital data storage devices 1000-1 to 1000-N. In other
embodiments, the devices 900-1 to 900-N may be different
types of devices capable transmitting data-modulated
optical carriers in M wavelength channels. In other
embodiments, the devices 1000-1 to 1000-N may be
different types of devices capable receiving and
processing data-modulated optical carriers in M
wavelength channels. The wavelengths of the M wavelength
channels of the machines 900-1 to 900-N may be, but need
not be, the same as the M wavelength channels of the
machines 1000-1 to 1000-N.
In some such embodiments, the system 100 enables
each of the N digital data processors to communicate a
separate digital data stream to any of the digital data
storage devices 1000-1 to 1000-N.
The optical components of the system 100 may be
formed conventionally, e.g. as planar structures formed
over a silicon substrate, e.g. a silicon wafer. A
convenient platform on which to form the system 100 is a
silicon-on— insulator (SOI) wafer, but embodiments of the
invention are not limited thereto. For example, a
dielectric layer, e.g. plasma oxide, could be formed on
any suitable substrate, and a silicon layer could be
formed thereover by any suitable method. Other
embodiments may use a substrate formed from, e.g. glass,
sapphire or a compound semiconductor. Those skilled in
the pertinent art are familiar with such fabrication
techniques .
In some embodiments optical and electrical
components of the system 100 are formed on a same
substrate. In such a system, e.g. silicon-based
electronic components may be formed on one region of a
photonic integrated circuit (PIC) , and optical components
may be formed on another region of the PIC. Interconnects
may provide conductive paths from the domain converters
300 to the electrical switching stage 110.
In other embodiments, such as represented by F Gs .
6A, portions of an opto-electronic system may be formed
on separate substrates. FIG. 6A illustrates a system 600,
formed according to one embodiment. Electrical components
are formed on an electrically active substrate 610,
optical components are formed on an optical substrate
620, and interconnects are formed on an interconnect
substrate 630. The substrates 610, 620 and 630 are then
joined to form the operable system 600.
The electronic substrate 610 may include electronic
components, e.g. transistors, diodes, resistors and
capacitors, needed to implement electrical functions of
the system 100. Such functions include, but are not
limited to, the switch 140 and the controller 145,
including switching, signal conditioning and
amplification. The electronic substrate 610 may include a
base layer 640, e.g. a silicon wafer, and an active layer
650 that includes electronic devices and interconnects.
The substrate 610 may be formed from any conventional
and/or future-discovered processes, and is not limited to
any particular material types. By way of example, without
limitation, such materials may include silica, SiN,
silicon, InP, GaAs, and copper or aluminum interconnects.
The optical substrate 620 includes various optical
components of the system 100, e.g. waveguides,
microcavity resonators, power splitters, power combiners,
and photodiodes. The optical components may be formed
from planar or ridge structures by conventional and/or
novel processes. Such components typically include a core
region and a cladding region. The core regions may be
formed from any conventional or nonconventional optical
material system, e.g. silicon, LiNbO , a compound
semiconductor such as GaAs or InP, or an electro-optic
polymer. Some embodiments described herein are
implemented in Si as a nonlimiting example. While
embodiments within the scope of the invention are not
limited to Si, this material provides some benefits
relative to other material systems, e.g. relatively low
cost and well-developed manufacturing infrastructure. The
cladding region may include homogenous or heterogeneous
dielectric materials, e.g. silica or benzocyclobutene
(BCB) . Some portions of the cladding region may include
air, which for the purposes of this discussion includes
vacuum.
The interconnect substrate 630 includes additional
interconnect structures that may configure operation of
the system 600. The interconnect substrate 630 may
include any dielectric and conductive (e.g. metallic)
materials needed to implement the desired connectivity.
In some cases, formation of the substrate 630 may include
the use of a handle wafer to provide mechanical support,
after which the substrate 630 is removed from the handle.
The electronic substrate 610 may be joined to the
interconnect substrate 630 by, e.g. a bump process or, as
illustrated, a wafer bonding process. Such processes are
well known to those skilled in, e.g. semiconductor
manufacturing, and may include chemical mechanical
polishing (CMP) to prepare the substrate surfaces for
bonding. The interconnect substrate 630 may be joined to
the optical substrate 620 by, e.g. a bump process as
illustrated in FIG. 6A, or a wafer bonding process as
illustrated in FIG. 6B . In the bump process, solder balls
660 join interconnect structures in the substrate 630 to
via structures 670 in the optical substrate 620. The via
structures 670 may provide electrical and/or mechanical
connectivity between substrates 620 and 630.
FIG. 6C illustrates another embodiment of the system
600 in which the interconnections and optical functions
are combined into an integrated substrate 680. In the
illustrated embodiment the substrate 680 includes the
optical substrate 620 and interconnect layers 630a and
630b formed on either side of the substrate 620. The
integrated substrate 680 may then be joined to the
electrical substrate 610 by, e.g. wafer bonding.
The separate formation of the electronic substrate
610, the interconnect substrate 630 and the optical
substrate 620 may serve at least one of several purposes.
First, the thermal budget required to form some features,
e.g. high quality waveguides in the optical substrate
620, may be incompatible with other features, such as
doping profiles of transistors in the substrate 610 .
Second, the substrates 610, 620 and 630 may be formed
separately by entities with specialized skills and/or
fabrication facilities and joined by another entity.
Third, where security is desired regarding the function
of the assembled system 600, the fabrication operations
may be assigned to the various entities such that no one
entity acquires sufficient knowledge to determine the
functionality of the device. The final assembly may then
be completed under secure conditions to provide
confidentiality of the operation of the assembled system
600 .
Turning to FIG. 7 , a method 700 is presented, e.g.
for forming the system 100 according to various
embodiments. The steps of the method 700 are described
without limitation by reference to elements previously
described herein, e.g. in FIGs . 1-6. The steps of the
method 700 may be performed in another order than the
illustrated order, and in some embodiments may be omitted
altogether and/or performed concurrently or in parallel
groups. This method 700 is illustrated without limitation
with the steps thereof being performed in parallel
fashion, such as by concurrent processing on a common
substrate. Other embodiments, e.g. those utilizing
multiple substrates, may perform the steps partially or
completely sequentially and in any order.
The method 700 begins with an entry 710. In a step
720, a first input waveguide, e.g. the input waveguide
120-1, is formed. This waveguide is configured to receive
a first input optical signal including a first modulated
input wavelength channel. In a step 730, a first output
waveguide, e.g. the waveguide 165-1, is formed. This
waveguide is configured to receive a carrier signal
including an unmodulated output wavelength channel. In a
step 740 a first input microcavity resonator, e.g. the
ring resonator 130-11, is formed. The ring resonator is
configured to derive a modulated electrical control
signal from the modulated input wavelength channel, e.g.
by transferring optical power to the domain converter
300. In a step 750, a first output microcavity resonator
is formed, e.g. the ring resonator 180-11. This
microcavity resonator is configured to modulate said
output wavelength channel in response to said control
signal .
FIG. 8 presents another method 800, e.g. for forming
the system 100. The steps of the method 800 are described
without limitation by reference to elements previously
described herein, e.g. in FIGs . 1-6. The steps of the
method 800 may be performed in another order than the
illustrated order, and in some embodiments may be omitted
altogether and/or performed in parallel or in parallel
groups. Herein and in the claims, "provided" or
"providing" means that a device, substrate, structural
element, etc., may be manufactured by the individual or
business entity performing the disclosed method, or
obtained thereby from a source other than the individual
or entity, including another individual or business
entity .
The method includes a step 810, in which a first
substrate is provided, e.g. the substrate 620. The
substrate includes an input waveguide, e.g. the waveguide
120-1, and an output waveguide, e.g. the waveguide 165-1.
An input microcavity resonator, e.g. the resonator 130-
11, is configured to derive a modulated electrical
control signal from a modulated input wavelength channel
propagating within the input waveguide. An output
microcavity resonator, e.g. the resonator 175-11, is
configured to modulate an output wavelength channel
propagating within the output waveguide in response to
the control signal.
In a step 820 a second substrate is provided, e.g.
the substrate 610. The second substrate includes a
control stage formed thereover, e.g. the electrical
switching stage 110. The control stage is configured to
route the electrical control signal from the input
microcavity resonator to the output microcavity
resonator .
In a step 830 the first and second substrates are
joined, thereby connecting the control stage to the
microcavity resonators .
In some embodiments of the method 800 joining the
first and second substrates includes joining both
substrates to a third substrate that includes conductive
interconnections that connect the controller to the
output microcavity resonator.
Those skilled in the art to which this application
relates will appreciate that other and further additions,
deletions, substitutions and modifications may be made to
the described embodiments.

WE CLAIMS:-
1 . A system, comprising
a first input waveguide configured to receive a
first input optical signal including a first modulated
input wavelength channel;
a first output waveguide configured to receive a
carrier signal including an unmodulated output wavelength
channel;
a first input microcavity resonator configured to
derive a modulated electrical control signal from said
modulated input wavelength channel; and
a first output microcavity resonator configured to
modulate said output wavelength channel in response to
said control signal .
2 . The system of Claim 1 , wherein:
said first input microcavity resonator is one of a
plurality of input microcavity resonators configured to
derive an electrical control signal from each one of a
corresponding plurality of modulated input wavelength
channels ;
said first output microcavity resonator is one of a
plurality of output microcavity resonators each
configured to modulate a corresponding output wavelength
— 9 ° —
channel in response to a corresponding one of said
control signals; and
a controller configured to reconfigure connectivity
between said input microcavity resonators and said output
microcavity resonators .
3 . The system of Claim 2 , wherein said controller
includes a cross-connect switch having configured to
provide a plurality of unique combinations of paths of
said control signals between said of input microcavity
resonators and said output microcavity resonators.
4 . The system of Claim 3 , wherein said crossconnect
switch has N inputs and N outputs, and includes a
plurality of sub-switches each being configured to switch
N inputs to outputs .
5 . The system of Claim 2 , wherein said input and
output waveguides are located on a first substrate and
said controller is located on a second substrate.
6 . The system of Claim 5 , wherein said first and
second substrates are both bonded to an interposed
interconnect substrate.
. A method, comprising
forming a first input waveguide capable of receiving
a first input optical signal including a first modulated
input wavelength channel;
forming a first output waveguide capable of
receiving a carrier signal including an unmodulated
output wavelength channel;
forming a first input microcavity resonator
configured to derive a modulated electrical control
signal from said modulated input wavelength channel; and
forming a first output microcavity resonator
configured to modulate said output wavelength channel in
response to said control signal.
8 . The method of Claim 7 , wherein:
said first input microcavity resonator is one of a
plurality of input microcavity resonators configured to
derive an electrical control signal from each one of a
corresponding plurality of modulated input wavelength
channels;
said first output microcavity resonator is one of a
plurality of output microcavity resonators each
configured to modulate a corresponding output wavelength
channel in response to a corresponding one of said
control signals; and
a controller configured to reconfigure connectivity
between said input microcavity resonators and said output
microcavity resonators .
9 . A system, comprising:
an NMxNM electrical cross-connect;
N first sets, each first set including M ring
resonators optically coupled to an optical waveguide
corresponding to the same first set, each ring resonator
of the first sets having an optical-to-electrical output
connected to a corresponding electrical input of an NMxNM
electrical cross-connect; and
N second sets, each second set including M ring
resonators optically coupled to an optical waveguide
corresponding to the same second set, each ring resonator
of the second sets having an optical-to-electrical input
connected to a corresponding output of the NMxNM
electrical cross-connect.
10. The system of claim S , further comprising N
optical transmitters capable of transmitting on M optical
transmission channels, each transmitter optically coupled
to a corresponding one of the optical waveguides
optically coupled to one of the first sets.