TW201605184A - Ultra-compact wavelength meter - Google Patents

Abstract

In some example embodiments there is provided an apparatus. The apparatus may include a first delay line passing a first portion of an optical signal to produce a first input signal. The apparatus may further include a second delay line passing a second portion of the optical signal to produce a second input signal. A combiner may combine the first input signal and the second input signal to produce a plurality of output signals. An analyzer may determine from the plurality of output signals at least a wavelength of the optical signal.

Description

Ultra-compact wavelength meter Field of invention

The subject matter described herein relates to optical communications, and in particular to determining the wavelength of a light source.

Background of the invention

Many electronic devices require sharing of information between devices. Such devices include a wide variety of consumer products and industrial products including mobile devices such as residential circuits, handheld computing devices, laptop computers and the like. As the number of features and capacity available in mobile devices increases, so does the need for higher throughput data links. For example, sharing high-definition video with another device via a data link requires a high-throughput data link between the devices.

Electronic devices can utilize optical communication between devices. Optical communication can include an optical transmitter in one device and an optical receiver in another device, and can include optical transceivers in both devices. The light emitter can include a light source such as a laser, a laser diode, a light emitting diode, or other light source. The performance of some light sources may drift over time and environmental conditions.

Summary of invention

One oriented to present a device. The apparatus can include a first delay line passing through a first portion of an optical signal to generate a first input signal. The apparatus can further include a second delay line passing through the second portion of the optical signal to generate a second input signal. A combiner can combine the first input signal and the second input signal to generate a plurality of output signals. An analyzer can determine at least one wavelength of the optical signal from the plurality of output signals.

In a number of variations, one or more of the features disclosed herein may optionally be included in any feasible combination. The first portion of the optical signal and the second portion of the optical signal can be generated by a 1x2 multimode interference coupler. The intensity of the first portion of the optical signal and the second portion of the optical signal may be equal or nearly equal. The device can further determine the line width of the optical signal. The combiner can include a multimode interference coupler. The multimode interference coupler can include a 4x4 multimode interference coupler. The combiner can include a 90 degree hybrid coupler.

The preface and features may be embodied in a system, apparatus, method, and/or computer readable medium, depending on the desired configuration. The details of one or more variations of the subject matter described herein are set forth in the accompanying drawings and the Detailed Description. The features and advantages of the subject matter described herein will be more apparent from the detailed description and the appended claims. In a number of specific embodiments, one of a variety of variations can be made and the partial descriptions and/or the following feature descriptions are described in detail below.

12‧‧‧Antenna

14‧‧‧transmitter

16‧‧‧ Receiver

20‧‧‧ processor

20a‧‧‧Internal Voice Encoder (VC)

20b‧‧‧Internal Data Machine (DM)

22‧‧‧Ringer

24‧‧‧Speakers

26‧‧‧Microphone

28‧‧‧Display

30‧‧‧Digital keypad

38‧‧‧User Identity Module (SIM)

40‧‧‧Electrical memory

42‧‧‧ Non-electrical memory

64‧‧‧RF Transceiver

66‧‧‧IR transceiver

68‧‧‧BT Transceiver

70‧‧‧Wireless USB Transceiver

110, 130, 140‧‧‧Action/fixing devices

112‧‧‧Free space optical transceiver

114, 140, 200A-B‧‧‧ wavelength meter

120‧‧‧ optical channel

142, 144‧‧‧ Free space input

146, 148‧‧‧ fiber input

210‧‧‧Optical input, input light source

220, 320, 350‧‧‧ path, delay arm

230, 330, 360‧‧‧ path, reference arm

240, 340, 370‧‧90 degree mix

242-248, 262-268‧‧‧ output

Section 252, 253‧‧‧

254-257‧‧‧Enter

310‧‧1x2 multiplier N multimode interference coupler

401‧‧1x4 multimode interference coupler

402, 403, 405‧‧4x4 MMI couplers

404‧‧3x3 MMI coupler

500‧‧‧ method

510-550‧‧‧

In the drawings, FIG. 1A depicts an example of a free-space optical transceiver system including a wavelength meter in accordance with several embodiments; 1B depicts an example of a wavelength meter in accordance with several embodiments; FIG. 2A depicts a schematic diagram of an optical component in a wavelength meter in accordance with several embodiments; FIG. 2B depicts a plurality of wavelength meters included in a wavelength meter in accordance with several embodiments. Mode Interference Coupler; Figure 3 depicts another example of a wavelength meter in accordance with several embodiments; Figure 4A depicts another example of a wavelength meter including a multimode interference coupler in accordance with several embodiments; Figure 4B depicts a number of embodiments in accordance with several embodiments An additional example of a wavelength meter including a multimode interference coupler; FIG. 5 depicts an example of a processing procedure performed by a wavelength meter in accordance with several embodiments; and FIG. 6 depicts an example of a device in accordance with several embodiments.

Similar component symbols are used to refer to the same or similar items in the drawings.

Detailed description of the preferred embodiment

Optical communication can be used to share data with other mobile devices or fixed location devices by electronic devices such as cell phones, portable computers, gaming devices, and the like. Optical communications can be embodied using cables such as fiber optic cables or cableless such as free space optical communications. In some cases, the cable is inconvenient or prone to failure because the cable needs to be connected and disconnected, but the connector may break. Or dirty and interfere with the operation and so on. In some cases, free-space optical communication is more robust and convenient. Free-space optical communication can be performed from an optical transmitter through an open medium to an optical receiver, such as from one mobile device to another through air.

The light emitter can include a light source and can also include other optical and electronic components. In several embodiments, the wavelength of light generated by the source of the emitter can be measured by a wavelength meter. The wavelength meter can be included as a component of the light emitter or can be a separate device. For example, the wavelength meter can be determined by the wavelength of the light source in a wavelength multiplex communication system. By using a wavelength meter to measure the wavelength of the source and adjust the wavelength of the source, wavelength drift of the source can be avoided. In several embodiments, the light source can be included in a piece of equipment that is not an emitter.

The light receiver can include a light detector and can also include other optical and electronic components. In some embodiments, the wavelength of the light of the light received at the optical receiver can be measured by a wavelength meter. The wavelength meter can be included as a component of the light receiver or can be a separate device.

The wavelength meter determines the wavelength of light incident on the wavelength meter. In several embodiments, the incident light is a narrow frequency, or the wavelength range of the incident light is small. In several embodiments, a wavelength meter comparable spectrometer or grating monochromator provides better accuracy. In several embodiments, a wavelength meter can be used to monitor the wavelength of a tunable laser or wavelength drifted laser.

A wavelength meter that meets the subject matter disclosed herein can determine the wavelength of incident light without the use of long-path techniques, such as users in spectrometers. In several embodiments, a wavelength meter consistent with the subject matter disclosed herein stabilizes the laser used to perform spectroscopy, and the laser wavelength must be accurately known. In several specific embodiments A wavelength meter consistent with the subject matter disclosed herein can be used to determine the wavelength of a tunable laser for cooling/capturing and/or differential absorption LIDAR (optical/light radar). In several embodiments, a wavelength meter consistent with the subject matter disclosed herein can be used in the testing and fabrication of dense wavelength division multiplexing (DWDM) devices for optical communications. In several embodiments, a wavelength meter consistent with the subject matter disclosed herein can incorporate a light source for quantum key distribution and/or sensing applications.

Figure 1A depicts a mobile or fixed location device in communication with another mobile or stationary device. In some embodiments, the optical transceiver can be coupled to a wireless device or user device, such as a smart phone, or a cell phone, and/or any other radio. One or both of the action/fixation devices can include a wavelength meter incorporated into the device.

For example, the mobile/fixing device 110 can include a free-space optical transceiver 112 and a wavelength meter 114. The mobile/fixing device 110 can communicate with the mobile/fixed device 130 via an optical channel 120, which can also include a free-space optical transceiver 112 and a wavelength meter 114. The communication between device 110 and device 130 can be half-duplex or full-duplex.

In some embodiments, the wavelength meter can be included in a communication transceiver embodying quantum key distribution. For example, digital communication between devices such as mobile/fixed device 110 and mobile/fixed device 130 may include quantum key distribution (also known as quantum communication) and/or modulated laser communication channels (also known as laser communication). For example, quantum communication can be embodied in optical transceiver 112. Laser-based communications can use lasers in the transmitter and detectors in the receiver. Furthermore, the data can be encoded using a key generated by quantum communication to ensure secure communication. In several embodiments, a single transmit and receive Photon. The wavelength meter can be used to determine the wavelength of the laser output or to determine the wavelength of the received signal. The wavelength meter can also be included with any other type of optical communication transceiver.

FIG. 1B depicts a wavelength meter 140 that can be used as a test device and/or as a diagnostic instrument. For example, the wavelength meter 140 can be used in a laboratory or manufacturing environment to determine the wavelength of the light source. The wavelength meter can have various inputs, such as free space input 142 and/or fiber input 148. The wavelength meter 140 can determine the wavelength of the light input to the free space input 142 and/or the fiber input 146.

In several embodiments, the wavelength meter of Figures 1A and 1B can measure orthogonal optical signals, which can be measured simultaneously or nearly simultaneously. In several embodiments, the optical input signal can be split into two or more portions using one or more beam splitters or other beam splitting devices. In several embodiments, the portions may each pass through different lengths of the waveguide or other material to cause a phase shift in proportion to the length. For example, an optical signal measures a portion of the split beam after a certain distance has elapsed, and measures another portion after a longer distance has passed to measure orthogonally.

In several embodiments, by performing quadrature measurements on a signal split into two paths, each path having a different length, the wavelength of the optical signal can be measured over a range of wavelengths, and the linewidth of the optical input can be determined. For example, an optical input signal can be split into two paths that have different lengths and are all connected to a 90 degree mix. The 90 degree blend produces four outputs that can be measured with four photodetectors and two photodetectors for each orthogonal component. In several embodiments, the metric values obtained from the four photodetectors may allow for the determination of the wavelength of the optical signal and the linewidth of the optical signal. Yu Ruo In a particular embodiment, the range of wavelengths may increase exponentially with the number of different path lengths and corresponding orthogonal measurement signals.

In several embodiments, multiple 90 degree hybrid couplers can be used to measure complex spectra, which can result in more information than a center wavelength and line width. In several embodiments, if the wavelength of the spectrum is sparse, the spectrum may be measured in a number of random delays (eg, wavelengths), such as in a compression sensing scheme. In several embodiments, the use of short (e.g., a few microns to tens of microns) fixed delays may make the wavelength metrics more robust to manufacturing margins and environmental fluctuations such as temperature, stress, and the like. In several embodiments, the predetermined accuracy of the wavelength metric can be determined without correction.

2A depicts a schematic diagram of several optical components in a wavelength meter in accordance with several embodiments. Optical input 210 can be split into two parts and transmitted via paths 220 and 230, each having a different length. After passing through paths 220 and 230, the two portions can enter a 90 degree blend 240. Each path can result in a different phase shift proportional to the length of the path/waveguide. The 90 degree blend 240 combines the two phase shifted signals to produce outputs 242-248. Based on the metrics of the four photodiodes at 262-268, the wavelength, linewidth, and other parameters of the optical input 210 can be determined. Wavelength meters consistent with the subject matter herein are further detailed in the latter paragraph.

In several embodiments, the wavelength meter can measure wavelength, line width, and/or other orientation of the light source. The source 210 to be measured may be equally divided, with a portion passing through a reference arm, such as reference arm 230 of Figure 2A, and another portion passing through a delay arm, such as delay arm 220 of Figure 2A. The delay arm 220 can be longer than the reference arm 230. The output from the reference arm and the output of the self-delay arm can be input with a 90 degree mix, such as a 90 degree mix 240. In several embodiments, the output from the 90 degree blend 240 can be expressed as being proportional to X ₊ at 242, X _- at 244, Y ₊ at 246, and Y _- at 248 according to: Where r is the composite amplitude of the signal from the reference arm and s is the composite amplitude of the signal from the delayed arm (s* is the conjugate complex number of s). The value of φ in Equations 1-4 may depend on a 90 degree blend (eg, the waveguide material used and the corresponding phase shift, any wave plates used, and/or whether a multimode interferometer (MMI) is used), and 220 The length of 230. The wavelength range and linewidth of the wavelength meter may depend on the difference in length between the reference arm 230 and the delay arm 220. For at least the reason, φ is a common phase offset value, and φ can be set to zero without loss of versatility in the following analysis.

In several embodiments, the intensity of the output of the 90 degree hybrid 240 can be measured by four photodetectors, one at each of 242-248. The intensity values of X ₊ , X _- , Y ₊ and Y _- can be used to calculate X = (X ₊ -X _- ), and Y = (Y ₊ -Y _- ). Photodetectors 242-248 can be photodiodes or any other type of photosensor or photodetector. In several embodiments, X and Y can be directly measured by a balance detector: X = ((C / 4) (|s + r | ² - | sr | ² )) = C (Re (sr *)) Equation 5, and Y = ((C / 4) (|s + ir | ² - | s - ir | ² )) = C (Im (sr *)) Equation 6, where C is the detector's responsivity . In several embodiments, the balance detector can provide results with reduced noise levels. The value r can be used as a phase reference, and the value s can be expressed as r multiplied by A phase shift where n is the modulus of the modulus, ΔL = L _{2 -} L ₁ , which is the difference in length between the reference arm and the delay arm, and λ is the center wavelength of the source.

In several embodiments, the following equation can represent the relationship between X and Y: Thus, Y/X can be independent of r (the magnitude of the reference source) and/or independent of C (the responsiveness of the detector).

In several embodiments, the range of measurable wavelengths can be related to the difference in length between the reference arm and the delay arm. In several embodiments, the difference in length between the reference arm and the delay arm that will produce the desired wavelength range can be determined according to the following equation: Where N is an integer, and 2πn ΔL/λ can be a determined modulus 2π, and atan2 has a value of -π<atan2(X, Y) The inverse tangent function of π. The length difference ΔL between the lengths of the reference arm and the delay arm determines the wavelength range Δλ for the wavelength meter. Such a range can be selected to include a range of wavelengths for the photodetector, or a range of light sources. Other values can also be used. For a central wavelength and range λ ₀ ± Δλ/2, ΔL can be selected to satisfy the following equation: Δ L = λ ₀ ² / n Δ λ Equation 9A.

The autocorrelation A(τ) of the optical signal for a delay τ = ΔL/c can be determined, where ΔL is the path length difference between the reference arm and the delay arm, and c is the speed of light. The autocorrelation can be determined as follows: Where S=X ₊ +X _- +Y ₊ +Y _- , the sum of all outputs, and < r ( t )* r ( t - τ )> denotes the volume of r(t) and r(t-τ) product.

The modulus of autocorrelation can be expressed as follows:

For the Lorentzian linewidth, the modulus of the autocorrelation can be exponentially reduced with delay as follows: | A ( τ )| = exp(- τ / τ _c ) Equation 14.

Based on |A(τ)| which is determined by the aforementioned metric, the coherence time τ _c can be determined, and the line width can be determined (in terms of frequency) as Δv = 1 / (π τ _c ).

2B depicts a multimode interference coupler included in a wavelength meter in accordance with several embodiments. A multimode interference (MMI) coupler, such as a 1x2 hybrid coupler 250, may implement a beam splitter or power splitter to divide the optical input signal/light source into equal or nearly equal portions, such as 252 and 254. A multimode interference coupler such as 4x4 MMI 260 may embody a 90 degree hybrid coupler, such as a 90 degree hybrid coupler 240.

In several embodiments, the 4x4 MMI 260 receives two input signals to produce four output signals. For example, one output from 1x2 MMI 250 passes through reference arm 230 (L ₁ ) to input 254 of 4x4 MMI 260, while the second output of 1x2 MMI 250 passes through input of delay arm 220 (L ₂ ) to 4x4 MMI 260 The 256. 4x4 MMI 260 can produce four outputs 262-268. Additionally, inputs 255 and 257 can produce outputs 262-268. In several embodiments, the MMI 260 performs the function of a 90 degree hybrid 240. Inputs 254 and 256 (or inputs 255 and 257) correspond to a 90 degree mix 240, output 262 corresponds to 242, output 264 corresponds to 244, output 266 corresponds to 246, and output 268 corresponds to 248. 90 degrees. Other manifestations of mixing are also possible.

In some embodiments, one end of the reference arm 230 (L ₁ ) can be coupled to the MMI 250 at 252 and the other end of the reference arm 230 (L ₁ ) can be coupled to the 4x4 MMI 260 at 254. To several specific embodiments, the delay end of the arm 220 (L ₂ which is longer than the reference arm 230) to 253 may be connected to the MMI 250, delay arm 220 (L ₂₎ at the other end of the link 256 to the 4x4 MMI 260.

Figure 3 depicts another example of a wavelength meter in accordance with several embodiments. In several embodiments, the wavelength meter can include a plurality of multimode interferometers (MMIs) to measure a broader range of wavelengths or more accurately measure a range of wavelengths. Figure 3 also refers to Figures 1-2.

For example, a 1x2 by N MMI 310 can split an input source 210 into 2N equal or nearly equal portions. The 2N portions can be linked to N 90 degree blends (eg, 4x4 MMI) via unequal length delays. In several embodiments, each 90 degree hybrid can be coupled to two outputs of the 1x2 by N MMI 310, one through the reference arm and the other through the delay arm, wherein the length of the delay arm for any 90 degree mixing is greater than The length of the corresponding reference arm is longer. The reference arms to the N 90 degree blends can have different lengths. For example, the 1x2 by N MMI 310 can be coupled to the 90 degree mixes 240, 340, and 370 through various length delays. The 1x2 by N MMI 310 can be transmitted through the reference arm 230. And the delay arm 220 is coupled to the 90 degree hybrid 240. The 1x2 by N MMI 310 can be coupled to the 90 degree hybrid 340 through the reference arm 330 and the delay arm 320. The 1x2 by N MMI can be coupled to the 90 degree hybrid through the reference arm 360 and the delay arm 350. 370.

To several specific embodiments, the first interferometer 240 may be determined in a range of wavelengths [lambda] △ λ a wavelength value falls within ₀ to ₀ wavelength accuracy within △ λ _1. The second interferometer 340 can have a range of wavelengths from the first interferometer 240 selected as Δλ ₁ , and due to the smaller wavelength range (Δλ ₁ < Δλ ₀ ), the interferometer 340 can determine that λ ₀ is different. High accuracy Δλ ₂ (Δλ ₂ <Δλ ₁ ). The combination of the first interferometer 240 and the second interferometer 340 produces a wavelength metric of the wavelength λ ₀ of the input source 210, which is measured by the first interferometer and falls within a higher accuracy Δλ ₂ . As such, in one embodiment, the range of wavelengths determined by the second interferometer is smaller but more accurate. The corresponding path length difference between the delay arm 320 and the reference arm 330 for the second interferometer 340 may be less than the path length difference between the delay arm 220 and the reference arm 230 for the first interferometer 240, resulting in a comparison of the second interferometer 340. Small wavelength range Δλ ₂ .

In several embodiments, a third 90 degree blend 370 can be included to obtain an accurate metric that is higher using two 90 degree blends 240 and 340. For example, the difference between the delay arm 350 and the reference arm 360 can be selected to obtain a wavelength range Δλ ₂ that is more accurate than the one provided by the second interferometer 340. Any target accuracy can be met by adding any suitable number of 90 degree blends. In several embodiments, an additional 90 degree blend extends the wavelength range of the metric.

Each interferometer can provide an autocorrelation of the difference in delay between its corresponding reference arm and delay arm. Can be determined by using several interferometers More information about the spectrum of this source. In some embodiments, if a light source has a frequency-sparse spectrum, the plurality of delayed delays of the plurality of interferometers and thus the associated autocorrelation points can support a compressed sensing scheme.

4A depicts an additional example of a wavelength meter including a 4x4 multimode interference coupler in accordance with several embodiments. 4A depicts a four-way power splitter coupled to two 90 degree hybrids through four different delays to provide eight outputs, thereby determining the wavelength and linewidth of the input source 210. Figure 4A also refers to Figures 1-3.

4A depicts a four-way power divider embodied as a 1x4 MMI coupler 401. The MMI coupler 401 splits the input source 210 into four outputs that are equal or nearly equal in magnitude. Two of the outputs of the 1x4 MMI 401 can be coupled to a 90 degree hybrid as a 4x4 MMI coupler 402. The reference arm L ₁ in FIG. 4A can connect the first output of the 1x4 MMI 401 to the 4x4 MMI 402, and the delay arm L ₂ can couple the second output of the 1x4 MMI 401 to the 4x4 MMI 402. The reference arm L ₃ in FIG. 4A can connect the third output of the 1x4 MMI 401 to the 4x4 MMI 403, and the delay arm L ₄ can connect the fourth output of the 1x4 MMI 401 to the 4x4 MMI 403. The wavelength and line width can be determined by the eight outputs (D ₁ -D ₈ ) of MMI 402 and 403.

In some embodiments, the lengths of L ₃ and L ₄ coupled to the 4x4 MMI 403 fall within the accuracy Δλ ₁ with a decision to permit the wavelength λ _{0 of the} input source 210 and the line width. In several embodiments, the lengths of L ₁ and L ₂ of the 4x4 MMI 403 can be selected to determine the wavelength in the smaller wavelength range Δλ ₁ to the higher accuracy Δλ ₂ , as described in detail with respect to FIG. In several embodiments, MMI 402 and MMI 403 can cover a diverse set of wavelength ranges.

4B depicts an additional example of a wavelength meter including a 3x3 multimode interference coupler in accordance with several embodiments. Figure 4B also refers to Figures 1-4A. Figure 4B depicts a four-way power splitter connected to two 120-degree hybrids through four different delays, embodied as a 3x3 MMI to provide six outputs (D ₁ -D ₃ , D ₅ -D ₇ ) from which it can be determined The wavelength and line width of an input light source 210.

In some embodiments, the lengths of L ₃ and L ₄ coupled to the 3x3 MMI 404 fall within the accuracy Δλ ₁ with a decision to permit the wavelength λ _{0 of the} input source 210 and the line width. In several embodiments, the lengths of L ₁ and L ₂ of the 4x4 MMI 405 can be selected to determine the wavelength in the smaller wavelength range Δλ ₁ to the higher accuracy Δλ ₂ , as described in detail with respect to FIG. In several embodiments, MMI 404 and MMI 405 can cover a diverse set of wavelength ranges. In several embodiments, the 120 degree blend can be more elastically corrected than the 90 degree blend and has a wider bandwidth than the 90 degree blend.

Although the 90 degree and 120 degree hybrid couplers are disclosed above, any other hybrid coupler can be used. For example, a 45 degree hybrid (embodied as 8x8 MMI) or a coupler with other phase relationships can also be used. In several embodiments, all inputs to the selected MMI can be used simultaneously. For example, the four inputs of the 4x4 MMI can be coupled to a four-way beam splitter via a reference arm and three different delay arms. The three phases can be determined from the metrics of the four inputs of the 4x4 MMI.

Figure 5 depicts an example of a method performed by a wavelength meter in accordance with several embodiments. At 510, the light source can be split into multiple sections. At 520, portions can be transmitted via a different length delay line, resulting in a different phase shift for one of the various portions. At 530, at least two of the phase shifting portions are A hybrid interferometer combination. At 540, the output of the hybrid interferometer can be measured. At 550, the output of the self-mixing interferometer determines at least one wavelength of the input source. Figure 5 also refers to Figures 1-4.

According to several embodiments, at 510, the light source can be split into multiple sections. For example, light source 210 can be split into two parts by a beam splitter such as the 1x2 multimode interferometer (MMI) coupler 250 of Figure 2B. In another embodiment, light source 210 can be split into four sections by a beam splitter such as the 1x4 multimode interference coupler 401 of Figures 4A/4B. In another embodiment, light source 210 can be split into 2N portions by a beam splitter such as the 1x2 by N multimode interference coupler 310 of FIG. Other beam splitters and/or multimode couplers can also be used to split the light source into multiple parts.

According to several embodiments, at 520, portions can be transmitted via a different length delay line, resulting in a different phase shift for one of the portions. For example, light source 210 can be split into two parts by a beam splitter such as the 1x2 multimode interference coupler 250 of Figure 2A. One portion can be mixed 240 by reference arm 230 to 90 degrees, and the second portion can be mixed 240 by a delay arm 220 to 90 degrees, as shown in Figure 2A. In another embodiment, shown in FIG. 2B, the first portion can pass through the reference arm 230 to 4x4 MMI coupler 260, and the second portion can pass through the delay arm 220 to 4x4 MMI coupler 260. In another embodiment, from FIG. 4A 1x4 multimode interference coupler portion 401 via four lengths L ₁ and L ₂ to 4x4 MMI 402, and a length L ₃ and L ₄ to 4x4 MMI 403 via. In another embodiment, light source 210 can be split into 2N portions by a beam splitter such as the 1x2 by N multimode interference coupler 310 of FIG. The 2N portion can pass 2N different delay lengths. Other lengths and types of couplers can also be used.

According to several embodiments, at 530, at least two of the phase shifting portions are combined in a hybrid interferometer. For example, in FIG. 2A, the portion 240 of the reference arm 230 and the second portion through the retard arm 220 can be combined at 90 degrees 240. In another embodiment, shown in FIG. 2B, the first portion through the reference arm and the second portion through the delay arm 220 can be combined at the 4x4 MMI coupler 260. In another embodiment, the length L ₁ and L ₂ of these portions may be in combination 4x4 MMI 402, and the length L ₃ and L ₄ those parts of the composition may be in the 4x4 MMI 403. In another embodiment, the 2N portions of 2N different lengths can be combined in pairs by N 90 degree blends. Other numbers of delays can also be combined. Other interference combiners, interferometers, and couplers can also be used.

According to several embodiments, at 540, the output of the hybrid interferometer can be measured. For example, the outputs 242-248 from the 90 degree blend 240 can be measured by four photodetectors such as photodiodes, or the four outputs can be measured by two balance detectors. In another embodiment, the output from the 4x4 MMI 260 shown in Figure 2B can be measured by four photodetectors or by two balance detectors. In another embodiment, eight outputs from 4x4 MMIs 402 and 403 can be measured by eight photodetectors or by four balance detectors, and/or six outputs from 3x3 MMIs 404 and 406 can be borrowed. Six photodetectors are measured. In another embodiment, the 4N outputs from the N90 degree blend of Figure 3 can be measured by 4N photodetectors or by 2N balanced photodetectors. Each photodetector can measure the optical power of one of the optical signals at one of the 90 degree mixing or MMI. For example, a detector such as D ₁ at 262 in FIG. 2B can measure a light output, such as light intensity, power level, or amplitude derived from one of the 4x4 MMI 260 outputs.

According to several embodiments, at 550, the output of the self-mixing interferometer can determine at least one wavelength of the input source. For example, any combination of Equations 1-14 above can be used to determine the wavelength and linewidth of the source. Other calculations can also be performed to determine the characteristics of the light source.

Figure 6 depicts an example of a device in accordance with several embodiments. The device 110 can include a user device such as a cell phone, a smart phone, and/or any other radio including a mobile and stationary radio.

In some embodiments, device 110 can include a free-space optical transceiver 112 and a wavelength meter 114. The free-space optical transceiver 112 in device 110 can be coupled to another device, such as another free-space optical transceiver in device 130 of FIG. In several embodiments, device 130 may be embodied in a manner similar to device 110. In several embodiments, the wavelength meter 140 can be embodied in a manner similar to the device 110.

In several embodiments, device 110 can establish communication with another device, such as device 130, using free-space optical transceiver 112. The wavelength meter 114 at the device 110 can monitor or determine the wavelength of an optical signal emitted from the device 110 and/or can determine the wavelength of an optical signal received from the device 130. Device 140 can determine the wavelength of the free-space optical signal or fiber-optic input signal.

In some embodiments, device 110 may also include a radio communication link to a cellular network or other wireless network. The device 110 can send a message to a network node of the radio network indicating the capabilities of the device 110. For example, device 110 can indicate the capabilities of the network node, including optical revenue. The capabilities of the transmitter 112 and/or the wavelength meter 114. The network node can enable device 110 to use its optical transceiver 112, and/or the network node can request device 110 to forward information from the network node or forward information from device 110 to another device, such as device 130. For example, a user of device 110 may have information that the user of device 110 would like to send to device 130, such as video or audio information.

Device 110 can include at least one antenna 12 in communication with transmitter 14 and receiver 16. In addition, the transmitting antenna and the receiving antenna can be separated.

The device 110 can also include a processor 20 configured to provide signals to and from the transmitter and receiver, respectively, and to control the functionality of the device. The processor 20 can be configured to control the functions of the transmitters and receivers by performing control communications through electrical leads to the transmitters and receivers. Similarly, processor 20 can be configured to control the functionality of such other components by performing control communications through the connection of processor 20 to other components of device 130, such as the electrical leads of the display or memory. The processor 20 can be implemented, for example, in a variety of ways, including circuitry, at least one processing core, one or more processors with digital signal processors, one or more processors without digital signal processors, one or more A coprocessor, one or more multi-core processors, one or more controllers, processing circuitry, one or more computers, various other processing elements including integrated circuits (eg, application specific integrated circuits (ASICs), Field Program Planning Gate Array (FPGA) and/or its class, or some combination thereof. The device 110 can include a positioning processor and/or an interface to obtain positioning information, such as positioning and/or navigation information. Accordingly, although illustrated as a single processor in FIG. 6, processor 20 may include multiple processors or processing cores in several specific embodiments.

The signals transmitted and received by the processor 20 may include communication information according to the air interface standard of the applicable cell system and/or any number of different wired or wireless networking technologies, including but not limited to Wi-Fi, wireless local area networks. (WLAN) technologies such as the American Society of Electrical and Electronics Engineers (IEEE) 802.11, 802.16, and/or the like. Additionally, such signals may include voice material, user generated material, user requested material, and/or the like.

Device 110 is capable of operating in one or more air interface standards, communication protocols, modulation types, access types, and/or the like. For example, the device 110 and/or the cellular data machine therein can be based on various first generation (1G) communication protocols, second generation (2G or 2.5G) communication protocols, third generation (3G) communication protocols, and fourth Generation (4G) protocol, Internet Protocol Multimedia Subsystem (IMS) protocol (eg, Session Initiation Protocol (SIP)), and/or its operations. For example, device 110 can be based on 2G wireless protocol IS-136, time-division multi-directional access (TDMA), global mobile communication system (GSM), IS-95, coded multi-directional access (CDMA), and / Or its operation. Moreover, by way of example, device 110 can operate in accordance with 2.5G wireless protocol General Packet Radio Service (GPRS), Enhanced GSM Environmental Data (EDGE), and/or the like. By way of example, the device 110 can be based on 3G wireless communication protocols, such as Universal Mobile Telecommunications System (UMTS), Coded Multi-Direct Access 2000 (CDMA2000), Wide Coded Multi-Direct Access (WCDMA), Time Division-Synchronization Code multi-directional access (TD-SCDMA), and/or its operations. Moreover, device 130 is capable of operating in accordance with a 3.9G wireless communication protocol, such as Long Term Evolution (LTE), Evolved Universal Terrestrial Radio Access Network (E-UTRAN), and/or the like. In addition, for example, The set 110 can operate in accordance with 4G wireless communication protocols, such as LTE Advanced, and/or classes thereof, and similar wireless communication protocols that will be developed later.

It is to be understood that processor 20 can include circuitry for embodying the audio/video and logic functions of device 110. For example, processor 20 may include a digital signal processor device, a microprocessor device, an analog to digital converter, a digital to analog converter, and/or the like. The control and signal processing functions of device 110 can be distributed among such devices based on their individual capabilities. Processor 20 may additionally include an internal voice coder (VC) 20a, an internal data modem (DM) 20b, and/or the like. Also, processor 20 may include functionality to operate one or more software programs stored in the memory. In general, processor 20 and stored software instructions can be assembled to cause device 110 to perform an action. For example, processor 20 is capable of operating a connection program, such as a web browser. The connection program allows device 110 to transmit and receive network content, such as location-based content, according to a protocol, such as Wireless Application Protocol (WAP), Hypertext Transfer Protocol (HTTP), and/or the like.

Device 110 may also include a user interface including, for example, a headset or speaker 24, a ringer 22, a microphone 26, a display 28, a user input interface, etc., operatively coupled to processor 20. As previously noted, display 28 can include a touch sensitive display where a user can touch and/or gesture for selection, loading values, and the like. Processor 20 may also include at least several functions in which the user interface circuitry is assembled with one or more of the user interfaces, such as speaker 24, ringer 22, microphone 26, display 28, and the like. The processor 20 and/or the user interface circuit including the processor 20 can be configured to transmit through a memory stored in the processor 20, such as an electrical record. The computer program instructions on the memory 40, the non-electrical memory 42 and the like, such as software and/or firmware, control one or more functions of one or more of the user interfaces. The device 110 can include a battery for powering various circuits associated with the mobile terminal, such as circuitry that provides mechanical vibration as a detectable output. The user input interface can include means for permitting device 110 to receive material, such as numeric keypad 30 (which can be a virtual keyboard or externally coupled keyboard displayed on display 28) and/or other input devices.

Moreover, device 110 can include a short range radio frequency (RF) transceiver and/or interrogator 64 that allows data to be shared and/or derived from the electronic device. Device 110 may include other short range transceivers, such as an infrared (IR) transceiver 66, a Bluetooth (BT) transceiver 68 that operates using Bluetooth wireless technology, a wireless universal serial bus (USB) transceiver 70, and the like. The Bluetooth transceiver 68 can operate according to low power or ultra low power Bluetooth technology, such as the Zigbee wireless standard. In this regard, device 110 is particularly a device that is capable of transmitting data to and/or receiving data from within the device, such as within 10 meters, for short-range transceivers. The device 110 includes a Wi-Fi or wireless area networked data machine that is also capable of transmitting and/or receiving data from the electronic device in accordance with various wireless networking technologies, including 6LoWpan, Wi-Fi, Wi-Fi low power, WLAN technologies such as IEEE 802.11 technology, IEEE. 802.15 technology, IEEE 802.16 technology, etc.

The device 110 can include a memory, such as a user identity module (SIM) 38, a mobile user identity module (R-UIM), etc., which can store relevant information elements of the mobile user. In addition to the SIM, device 110 can include other removable and/or fixed memory. Device 110 can include an electrical memory 40 and/or a non-electrical memory 42. For example, the electrical memory 40 can include random The access memory (RAM) contains dynamic and/or static RAM, on-wafer or non-on-wafer memory. The non-volatile memory 42 that may be embedded and/or active may include, for example, a read-only memory, a flash memory, a magnetic storage device such as a hard disk, a floppy disk drive, a magnetic tape, a CD player, and/or a media. Non-electrical random access memory (NVRAM). Similar to the electrical memory 40, the non-electrical memory 42 can include a cache area for temporary storage of data. At least a portion of the electrical and/or non-electrical memory can be embedded within the processor 20. The memory can store one or more software programs, instructions, block information, data, etc., which can be used by the device to perform functions of the user device/mobile terminal. The memory can include an identifier, such as an International Mobile Equipment Identity (IMEI) code that can uniquely identify device 110. Such functions may include one or more of the operations disclosed herein for free space optical communications, including the processing flow of FIG. The memory may include an identifier capable of uniquely identifying device 110, such as an International Mobile Equipment Identity (IMEI) code. In this particular embodiment, processor 20 may use computer code sets stored in memory 40 and/or 42 to provide operations disclosed in the method shown in FIG.

Several embodiments disclosed herein may be embodied in software, hardware, application logic, or a combination of software, hardware, and application logic. Software, application logic, and/or hardware may reside, for example, in memory 40, control device 20, or electronic components disclosed herein. In some embodiments, the application logic, software, or instruction set is maintained on any of a variety of conventional computer readable media. In the context of this document, a "computer-readable medium can be any non-transitory medium that can contain, store, communicate, propagate, or transmit instructions for use by or in conjunction with an instruction execution system, device, or device, such as a computer or device. Processor circuits, embodiments are depicted in Figures 1A, 1B, 2A, 2B, 3, 4A, 4B, 5, and/or 6. The computer readable medium can comprise a non-transitory computer readable storage medium and can be any medium that can contain or store instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer. Again, several embodiments disclosed herein include computer programs that are configured to cause a method as disclosed herein (e.g., with reference to the processing routine of FIG. 5, etc.).

The subject matter described herein can be implemented in a system, apparatus, method, and/or article depending on the desired configuration. For example, the systems, devices, methods, and/or articles described herein can be embodied using one or more of the following: electronic components such as transistors, inductors, capacitors, resistors, etc., processors that execute code Application specific integrated circuit (ASIC), digital signal processor (DSP), embedded processor, field programmable gate array (FPGA), and/or combinations thereof. The various embodiments may be embodied in one or more computer programs, which may be executed and/or interpreted on a programmable system, including at least one programmable processor, which may be special or generic, coupled. Receiving data and instructions from and transmitting data and instructions to the storage system, at least one input device, and at least one output device. Such computer programs (also known as programs, software, software applications, applications, components, code or code) include machine instructions for programmable processors and are available in high-level programs and/or object-oriented programming languages, and/or Or implemented in combination/machine language. As used herein, the term "machine-readable medium" means any computer program product, computer-readable medium, for providing machine instructions and/or information to a programmable processor, including a machine readable medium having its receiver instructions. Computer readable storage media, devices, and/or devices (eg, magnetic disks, optical disks, memories) Body, programmable logic device (PLD)). Similarly, a system including a processor and a memory coupled to the processor is also described herein. The memory can include one or more programs that cause the processor to perform one or more of the operations described herein.

The technical effect of one or more of the specific embodiments disclosed herein is to limit the wavelength and/or line width of a light source more accurately, without limiting the scope, interpretation, or application of the scope of the claims.

Although several variations have been described in the foregoing, other modifications or additions are possible. More specifically, further features and/or modifications may be made in addition to those set forth herein. Furthermore, the foregoing specific embodiments may be combined with various combinations and sub-combinations of the disclosed features and/or combinations and sub-combinations of several further features disclosed herein. In addition, the logic flow depicted in the drawings and/or described herein does not require a particular order or sequence of steps to be performed to achieve a desired result. Other embodiments may fall within the scope of the following claims.

200A‧‧‧wavemeter

210‧‧‧Input light source

220‧‧‧delay arm

230‧‧‧ reference arm

240‧‧90 degree mixing

242-248‧‧‧ Output

Claims (16)

A device comprising: a first delay line passing through a first portion of an optical signal to generate a first input signal; a second delay line passing through a second portion of the optical signal to generate a second input signal; The combiner is configured to combine the first input signal and the second input signal to generate a plurality of output signals, wherein the combiner is a hybrid coupler; and an analyzer is configured to determine at least the optical signal from the plurality of output signals One wavelength. The apparatus of claim 1, wherein the hybrid coupler has a phase difference between the outputs. The apparatus of claim 2, wherein the phase difference between the outputs is significantly different from the zero modulus of 180 degrees. The device of claims 1 to 2, wherein the hybrid coupler is a 90 degree or 120 degree hybrid coupler. The device of claim 1, wherein the combiner is a multimode interference coupler. The device of claim 1, wherein the first portion of the optical signal and the second portion of the optical signal are generated by a 1x2 multimode interference coupler, and wherein the first portion of the optical signal and the optical signal The strength of the second part is equal or nearly equal. The device of claim 1, wherein the device is further configured to determine One of the optical signals has a line width. The device of claim 5, wherein the multimode interference coupler is a 4x4 multimode interference coupler. A method comprising: delaying a first portion of an optical signal to generate a first input signal in a first delay line; delaying a second portion of the optical signal to generate a second in a second delay line a second input signal; combining the first input signal and the second input signal to generate a plurality of output signals, wherein the combination is by a hybrid coupler; and determining at least one wavelength of the optical signal from the plurality of output signals . The method of claim 9, wherein the combination is performed by at least one multimode interference coupler. The method of claim 9, wherein the hybrid coupler has a phase difference between the outputs. The method of claim 11, wherein the phase difference between the outputs is significantly different from the zero modulus of 180 degrees. The method of claim 11, wherein the hybrid coupler is a 90 degree or 120 degree hybrid coupler. The method of claim 9, wherein the first portion of the optical signal and the second portion of the optical signal are generated by a 1x2 multimode interference coupler, and wherein the first portion of the optical signal and the optical signal The strength of the second part is equal or nearly equal. The method of claim 9, further comprising determining a line of the optical signal width. The method of claim 9, wherein the multimode interference coupler is a 4x4 multimode interference coupler.