160 results about "Free spectral range" patented technology

The invention provides a double-optical-comb-cavity modulated gas measurement system and method based on electro-optical modulation, in the use process, a detection optical comb and a reference optical comb which are coherent are generated through a double-optical-comb output module, the detection optical comb enters a resonant cavity to interact with gas to be measured, and the reference optical comb directly reaches a data acquisition and analysis module; the data acquisition and analysis module is communicated with the resonant cavity and the double-optical-comb output module, and is used for receiving the reference optical comb and the detection optical comb output from the resonant cavity, and performing component and concentration analysis on the to-be-detected gas according to the detection optical comb and the reference optical comb; in the measuring process, the electro-optical modulation module is used for acquiring the detection optical comb output from the resonant cavity in real time, and the optical field of the detection optical comb in the resonant cavity is dynamically modulated based on the detection optical comb, so that the optical comb mode is matched with the free spectral range of the resonant cavity in real time, and efficient coupling is formed in the resonant cavity; the influence of the gas dispersion effect on the measurement precision is eliminated.

The invention discloses an optical computing array based on micro-ring resonators without a free spectral range, which comprises an on-chip wavelength division multiplexing beam splitting array, an on-chip intensity modulation array, two groups of on-chip wavelength division multiplexing beam combining arrays and an on-chip balance detector, the on-chip wavelength division multiplexing beam splitting array and the on-chip wavelength division multiplexing beam combining array are respectively composed of a group of multiple FSR-free MRRs which share the same bus optical waveguide, each resonator corresponds to an independent wavelength channel, and the on-chip intensity modulator array is composed of a plurality of groups of on-chip MZI modulator arrays. According to the optical calculation array implementation method, independent control and coding calculation of different wavelength channels in a broadband wavelength range are realized by utilizing the single harmonic peak characteristic of the FSR-free MRR array and the wide-spectrum intensity modulation function of the MZI unit, the limitation of a free spectrum range on the optical calculation wavelength channel is eliminated, the higher wavelength parallelism is achieved, and the optical calculation array implementation method has the advantages of being simple in structure and convenient to implement. And therefore, the calculation scale is remarkably improved.

The invention provides a vernier effect-based micro-ring resonant cavity acoustic sensor, and belongs to the technical field of optical-acoustic sensors. Comprising a coupling unit; the light source is used for generating light signals; the cascade sensing ring unit comprises a front-stage sensing ring and a rear-stage reference ring, one end of the front-stage sensing ring is connected with a light path of the light source, and the other end of the front-stage sensing ring is connected with a light path of one end of the rear-stage reference ring through the coupling unit; wherein each of the front-stage sensing ring and the rear-stage reference ring comprises a hollow plate glass substrate, a first PDMS thin film, a micro-nano optical fiber knot and a second PDMS thin film which are sequentially stacked, and the two ends of the micro-nano optical fiber knot in the axial extension direction serve as the two ends of the sensing ring; the radius and the free spectral range of the micro-nano optical fiber junctions of the front-stage sensing ring and the rear-stage reference ring are different. The micro-nano optical fiber knot and the multi-stage sensing ring structure are adopted, the acoustic sensor can accurately detect weak acoustic pressure change, and the sensing ring is very sensitive to wavelength drift and acoustic pressure change.

The present disclosure is applicable to a field of laser radar technology and provides a resonance module, a silicon-based external cavity chip, a laser, and a laser radar. The resonance module includes multiple main resonators and at least one auxiliary resonator, both of the main resonators and the auxiliary resonator are tunable micro-ring resonators; the multiple main resonators are cascaded in sequence through a connecting module to form a cascaded structure, and a vernier effect can be formed between two adjacent main resonators; when an auxiliary resonator is provided for matching the main resonator, coupling of the main resonator and the auxiliary resonator that are provided in a matching manner expands a free spectrum range of the main resonator. The tunable range of lasers applied to the laser radar and improve the scanning angle of the laser radar can be expanded.

The invention relates to a high-performance silicon-based heat insulation micro-ring design method and system, and belongs to the technical field of photoelectrons. Comprising the following steps: drawing a half outer contour curve of a to-be-designed micro-ring by utilizing double Euler bending according to a free spectral range of the to-be-designed micro-ring; using the N-order Bezier curve and optimizing control point coordinates of the N-order Bezier curve according to a transmission loss minimum principle, and drawing a half inner contour curve of the to-be-designed micro-ring; wherein N is a positive integer greater than 1; the transmission loss is half micro-ring transverse electric field 0-order mode transmission loss; obtaining a half optimized micro-ring according to the half outer contour curve and the half inner contour curve; and splicing the two half optimized micro-rings into a complete micro-ring. According to the invention, serious mode loss occurring when a wider multi-mode waveguide is used and serious bending loss occurring when a small bending radius design is adopted are avoided, and the problem that the doping space of the micro-ring is narrow due to the limited waveguide width is solved. And meanwhile, the free spectral range of the micro-ring is enlarged.

The invention discloses a double-layer waveguide 2 * 2 microring optical switch, an optical switch array thereof and an optical signal processing method, and belongs to the technical field of optical communication devices. Aiming at the technical problem that a traditional micro-ring optical switch is difficult to realize a large free spectral range and low-loss transmission at the same time, the invention provides an innovative structure combining a silicon nitride micro-ring resonator and an annular Bragg grating, and the outer side of the silicon nitride micro-ring resonator is nested with the annular Bragg grating; and a light field forbidden band is constructed to suppress a light field radiated outwards by the resonator, so that strong light field constraint is realized to remarkably reduce bending loss. A silicon-silicon nitride double-layer waveguide interlayer coupling technology is adopted, the lower layer is a silicon coupling waveguide, the upper layer is a silicon nitride micro-ring resonator and concentric annular grating structure, and a titanium nitride micro-heater is integrated to adjust the resonant wavelength. The invention effectively solves the technical problem that the silicon nitride micro-ring optical switch is difficult to obtain in the aspects of large free spectral range and low loss at the same time, and is a key technical support for constructing a high-integration wavelength selection optical switching chip.

A photonic integrated circuit has an asymmetric dual ring resonator. The asymmetric dual ring resonator includes a first ring having a first effective length and a second ring having a second effective length, which is distinct from the first effective length. The first effective length and the second effective length are near integer multiples of a third effective length. The third effective length is within about an order or magnitude of the first effective length and the second effective length. The asymmetric dual ring resonator has a free spectral range corresponding to a single ring resonator having the third effective length but has a lower sensitivity to manufacturing process variations than would a single ring resonator having the third effective length.

The invention relates to an optical radiation source. It is an object of the invention to enable the generation of laser radiation with (ultra) narrow linewidth and to provide an optical radiation source which is robust and simple to control. The optical radiation source of the invention comprises: a laser source having a gain medium and an internal cavity configured to generate laser radiation at multiple frequencies separated by a first free spectral range, at least one external cavity in optical communication with the laser source, the external cavity having a plurality of resonance modes within the gain bandwidth of the laser source, wherein the resonance modes are separated by a second free spectral range which is different from the first free spectral range, wherein the external cavity is configured to act as a frequency-selective reflector to selectively reflect laser radiation generated by the laser source back into the gain medium, thereby causing the gain medium to lase predominantly at only one frequency, and wherein the optical radiation source is configured to couple a portion of the generated laser radiation out from the internal cavity and / or from the external cavity.

The invention relates to the technical field of optical fiber sensors, in particular to a double-parameter optical fiber sensor based on a double interference effect and a preparation method thereof.The sensor comprises a sensing unit 5 based on a Fabry-Perot interferometer and a sensing unit 6 based on a Mach-Zehnder interferometer, and the two sensing units form a cascade structure; mutual reference probes can be realized when different parameters are measured; according to the invention, an approximate free spectral range is obtained by controlling the cavity length, a remarkable vernier effect is formed, the air pressure and temperature sensitivity can be calculated by tracking the drift of the envelope, the measurement accuracy can be effectively improved, and the device has the advantages of simple structure and small volume.

The invention discloses a tunable laser mode hopping and fluctuation detection method based on an F-P etalon, mainly relates to the technical field of fiber bragg grating sensing, and is used for mode hopping and fluctuation detection and repair. The method comprises the following steps: firstly, building a fiber grating demodulation system based on F-P etalon, determining the free spectral range FSR and fineness F of a single F-P etalon according to the demodulation precision of the system, calculating the peak width W of the F-P etalon and the number M of the F-P etalon, then carrying out a prior experiment on light path channels corresponding to the M F-P etalon, and finally, carrying out a prior experiment on the M F-P etalon. And calculating optical signal reference data and optical signal measurement data of the optical path of the F-P etalon, carrying out mode hopping and power fluctuation judgment and correction on the tunable laser based on the optical signal reference data and the optical signal measurement data of the optical path of the F-P etalon, and carrying out Bragg grating central wavelength demodulation by the fiber grating demodulation system based on the corrected data.

Examples include a tunable laser, in particular, an external cavity type laser. Examples also include a method of operating the tunable laser. The tunable laser is designed for fast and repeatable wavelength tuning over a wide wavelength range. The tunable laser includes a cavity and a gain medium arranged in the cavity. The gain medium is configured to generate light by stimulated emission and to emit the light into the cavity. The tunable laser also includes a laser output configured to output a portion of the light in the cavity as a laser beam. The cavity includes a first resonator and a second resonator that are optically coupled to each other. A resonance frequency of the first resonator is tunable. A free spectral range (FSR) of the second resonator is an integer multiple of an FSR of the cavity.

A device including a photonic integrated circuit comprising one or more OPOs each comprising: an input configured to receive a pump wave comprising pulses or a frequency comb with a pump repetition rate, one or a plurality of nonlinear sections as part of a resonator or coupled to a resonator having a free spectral range, where at least one of the free spectral range or one of its harmonics is matched to the pump repetition rate or its harmonics, and one or a plurality of outputs configured to extract a portion of the waves generated by the OPO in response to the pump wave and / or the pump wave.

The invention discloses a micro-ring modulator with a large free spectral range and a design method of the micro-ring modulator, and belongs to the field of optoelectronic devices. A micro-ring resonant cavity corresponding to the micro-ring modulator comprises an annular waveguide, and the width of the annular waveguide is an optimized width value, so that the integral value of the group refractive index of an optical mode in the annular waveguide along a closed optical path of the annular waveguide is minimized, and meanwhile, the width is ensured to be smaller than a cut-off width supporting high-order optical mode propagation. Through the design of accurately regulating and controlling waveguide dispersion, the free spectral range of the device can be maximized on the premise of ensuring single-mode work. In addition, an asymmetric electro-optical modulation structure can be arranged on the annular waveguide so as to be matched with a distorted optical mode, and high modulation efficiency is guaranteed. The micro-ring device with ultra-large FSR, high bandwidth, high efficiency and compact size can be realized, and the micro-ring device has important application value in the field of high-density optical interconnection.

The present invention belongs to the technical field of ammonia concentration detection, and discloses an ammonia concentration detection system, method, interferometer FPI1 and preparation method of FPI2, including: a light source, a first circulator, a second circulator, an interferometer FPI1, an interferometer FPI2 and a spectrometer; the light source emits a detection light, enters the A port of the first circulator and outputs the detection light to the interferometer FPI1 through the B port of the first circulator, the interferometer FPI1 reflects the detection light to the B port of the first circulator, and outputs the detection light to the A port of the second circulator through the C port of the first circulator, the detection light is output to the interferometer FPI2 through the B port of the second circulator, the interferometer FPI2 reflects the detection light to the B port of the second circulator, and outputs the detection light to the spectrometer through the C port of the second circulator. The technical solution of the present invention can accurately control the free spectral range of the two interferometers to produce a vernier effect, thereby improving the sensitivity of ammonia detection.

The present invention concerns a tunable Dense Wavelength Division Multiplex (DWDM) intra cavity laser device having a first optical wave guide having a first optical grating section, a second optical wave guide having a second optical grating section, an active gain section spatially separated from the second optical grating section and a phase section, and a DWDM-filter having an intra-cavity ring resonator located between the first optical wave guide and the second optical wave guide for coupling optical waves between the first and second optical wave guides. The tunable laser device is tunable in a discrete manner depending on a length of the ring resonator that is selected such that the free spectral range of the ring resonator matches a predetermined fixed wavelength spacing grid.

The application belongs to the technical field of optical communication and relates to a frequency-shift-free microwave photonic channelized receiving device, which comprises a carrier light frequency comb generating unit, a local light frequency comb generating unit, an electro-optical modulation unit, an optical phase shift unit, a channel selection and spectrum processing unit and a plurality of photoelectric conversion units. The received broadband radio frequency signal is modulated on each comb tooth of the carrier light frequency comb through the electro-optical modulation unit, and the frequency alignment between the optical local oscillator and the required receiving sub-channel can be realized based on the "vernier" effect caused by the different free spectral ranges of the carrier light frequency comb and the local light frequency comb and the inherent frequency alignment of the same pump laser. The mirror image sub-channel suppression is realized based on the opposite optical phase shifts on both sides of the pump light. The application has a simple structure, omits the frequency shift and special modulation structure required for frequency alignment, effectively suppresses the inter-channel crosstalk problem in the channelized receiving process, and can flexibly increase the channelization quantity according to actual needs.

This invention belongs to the field of optical device technology and discloses a microring filter and its design method. The invention utilizes a three-dimensional finite-difference time-domain algorithm to establish a simulation model of the microring filter, which includes a microring region and a coupled waveguide region. Based on a set free spectral range and a set coupling coefficient, with the fundamental mode transmittance as the optimization objective, a first curve is used as the waveguide center curve, and a second curve is used to adjust the waveguide width. The microring region and the coupled waveguide region are then designed in reverse, and iterative optimization yields a set of optimal microring structure parameters and a set of optimal coupled waveguide structure parameters, thus completing the design of the microring filter. This invention can significantly improve the free spectral range and enhance the loss performance of the microring filter.

Embodiments of the invention relate to photonic integrated circuit devices and methods of forming the same. A photonic integrated circuit device has an asymmetric double ring resonator. The asymmetric double ring resonator includes a first ring having a first effective length and a second ring having a second effective length different from the first effective length. The first effective length and the second effective length are close to an integer multiple of the third effective length. The third effective length is within about one magnitude or order of magnitude of the first effective length and the second effective length. The asymmetric double-ring resonator has a free spectral range corresponding to a single-ring resonator having a third effective length, but is less sensitive to manufacturing process variations than a single-ring resonator having a third effective length.

The invention provides an F-P spectral imaging system and method, and belongs to the technical field of spectral component measurement, and the system comprises a front lens which is used for collecting light energy and converting the light energy into emergent light meeting the limitation of the clear aperture of an F-P interferometer; the annular band optical filter comprises a central area and a plurality of concentric annular areas surrounding the central area, the bandwidth of each area is the same as the free spectral range of the F-P interferometer, and the annular band optical filter is used for eliminating level aliasing in emergent light of the front lens; the F-P interferometer is used for carrying out wavelength selection on emergent light of the annular band optical filter and outputting an interference field; the imaging mirror is used for projecting the interference field to the detector; and the detector is used for converting the projected optical signal into a digital electric signal. The F-P spectral imaging system which can maintain high spectral resolution and also can realize wide spectrum coverage is constructed by introducing the annular band optical filter which is accurately matched with the FSR of the F-P interferometer.

This application provides a self-injection-locked narrow-linewidth laser with a quasi-continuous locking region, comprising: a semiconductor laser source for generating an initial linewidth laser and outputting it via end-face coupling; a photonic integrated microcavity chip including a bus waveguide and a microring resonator coupled to it via an evanescent wave, for receiving the initial linewidth laser and providing feedback light to the semiconductor laser through Rayleigh backscattering of the microring resonator to excite a self-injection-locking effect; the microring resonator is a compact folded waveguide microcavity with an ultra-low free spectral range, the free spectral range of which is less than a preset threshold, so that when the driving current of the semiconductor laser is changed for wavelength tuning, the self-injection-locking regions of adjacent resonant modes in the cavity physically overlap or are closely spliced ​​in the current tuning parameter space, so that the semiconductor laser can continuously transition between adjacent modes without experiencing permanent unlocking during continuous current tuning, forming a quasi-continuous locking region.

The present application belongs to the technical field of photonic device design, and specifically relates to a micro-ring resonator reverse design optimization method based on deep learning. The present application comprises: obtaining different micro-ring resonator structure parameters and corresponding free spectral range and quality factor, and processing and dividing the data set; building a cascade neural network model, wherein the reverse network takes the target performance index as the input to predict the structure parameter, the forward network inputs the structure parameter and outputs the performance index, and is used to constrain and correct the reverse prediction result; after training, the test set is evaluated to measure the reverse effect by the average absolute percentage error index, the weight in the loss function is changed, and multiple rounds of training are performed to determine the optimal weight configuration and final model of the reverse design. The present application has the advantages of high calculation efficiency, excellent design precision and strong physical realizability, can reduce the dependence on large-scale simulation and multiple iteration optimization, effectively shorten the device design cycle, and has high application value.

The utility model relates to a temperature adjustable OCM or TOF, comprising two oppositely arranged optical fiber collimators, an ultra-thin etalon and a silicon-based etalon are sequentially arranged between the two optical fiber collimators, the ultra-thin etalon is formed by plating a-Si, SiH or GeH film on a silicon substrate, and the silicon-based etalon is formed by plating a-Si, SiH or GeH film on the silicon substrate. The ultra-thin etalon and the silicon-based etalon are respectively connected with a temperature controller for adjusting the temperatures of the ultra-thin etalon and the silicon-based etalon; the line width of the ultra-thin etalon is smaller than the free spectral range of the silicon-based etalon, and the line width top of the ultra-thin etalon is always and synchronously sleeved above one transmission wavelength of the silicon-based etalon along with the temperature change; when pulse or quasi-pulse is used for rapid adjustment, the OCM is used as a high-resolution OCM; during low-speed adjustment, the TOF serves as a narrow or ultra-narrow bandwidth TOF. According to the utility model, the advantages of both the film-coated etalon and the silicon-based etalon are combined, and the degree of freedom is higher.

The application discloses a kind of based on functional echo wall mode optical microbottle cavity Full light tuning controllable optical comb generation method. Including 1550nm narrow line width continuous wave laser, single-mode optical fiber, erbium-doped fiber amplifier, polarization controller, optical isolator, functional microbottle cavity-fiber taper coupling system, optical attenuator, optical spectrum analyzer and 1550nm power adjustable laser. The unique axial characteristics of echo wall mode microbottle cavity are used, the free spectral range of microcavity is reduced, the axial mode microcavity optical frequency comb with small free spectral range is generated, and based on full light tuning method, functional microbottle cavity is prepared, and the axial mode microcavity optical frequency comb generated is tuned by photo-thermal material titanium dioxide, and significant spectral range tuning is realized. The application solves the limitation that WGM microcavity optical frequency comb cannot be effectively tuned due to large free spectral range, and helps the practical application in the field of microcavity optical frequency comb optical communication, optical frequency synthesis and the like.

The invention discloses a method for measuring a residual birefringence difference value of a transparent ferroelectric electro-optical material based on a Fabry-Perot resonant cavity. The method comprises the following steps: constructing a Fabry-Perot resonant cavity measuring light path consisting of a broadband light source, a polarization control assembly and a sample to be measured; the polarization state of incident light is accurately controlled through a magnetic control Faraday rotating mirror, and transmission spectrums in the o-light direction and the e-light direction are obtained respectively; a high-precision spectrum acquisition module is adopted to record transmission spectrum characteristics; based on an original spectrum processing algorithm, the residual birefringence difference value of the to-be-detected material is calculated by analyzing the resonant wavelength offset and the free spectrum range change of the o-light and e-light transmission spectrums. The method solves the problem that the weak birefringence detection capability of the existing measurement technology is insufficient, has the advantages of high measurement precision, strong anti-interference capability and the like, and is suitable for performance evaluation, process optimization and device performance improvement of the transparent ferroelectric electro-optical material.

A method for characterizing a resonator element (102) is provided, the method comprising the steps of providing laser light having a tunable carrier frequency and coupling at least a first portion of the laser light into a resonator element (102) having a plurality of carrier resonances (3000) for the carrier frequency of the laser light, wherein adjacent carrier resonances (3000) are spaced apart from one another within a spectral range by a free spectral range (FSR). The method further includes modulating the intensity and / or phase of the portion of the laser light coupled into the resonator element (102) with a first modulation frequency (1001) and a second modulation frequency (1002) to generate, for each carrier resonance (3000), at least two sideband resonances (3001) spaced from the carrier resonance (3000) by the first modulation frequency (1001) and at least two sideband resonances (3002) spaced from the carrier resonance (3000) by the second modulation frequency (1002), wherein the first modulation frequency (1001) and the second modulation frequency (1002) are integer multiples of the free spectral range and are different from each other. The method further includes tuning the carrier frequency of the laser light at a predetermined tuning speed and measuring the intensity of the laser light transmitted and / or reflected by the resonator element (102) while tuning the carrier frequency. Furthermore, the method includes measuring a tuning time elapsed in tuning the carrier frequency across four adjacent sideband resonances (3001, 3002), the tuning time corresponding to the time required to change the tunable carrier frequency from a value corresponding to the first of the four sideband resonances to the last.The method further includes determining the spacing between multiple carrier resonances (3000) within the spectral range using the measured intensity of the laser light transmitted and / or reflected by the resonator element (102), the first modulation frequency (1001), the second modulation frequency (1002), and the tuning time measured when tuning the carrier frequency across four adjacent sideband resonances (3001, 3002).

The present invention proposes an optical fiber vibration sensor, preparation method, detection system and application method, including a capillary, a single-mode optical fiber, a few-mode optical fiber and a film layer, wherein the capillary has an air cavity; the single-mode optical fiber and the few-mode optical fiber each have one end plugged into the capillary, the end faces of the single-mode optical fiber and the few-mode optical fiber are opposite, and the single-mode optical fiber and the few-mode optical fiber do not contact the capillary; the film layer is arranged on one end of the few-mode optical fiber away from the single-mode optical fiber. The present invention uses single-mode and few-mode optical fibers to prepare sensors, and the types of transmission modes are relatively small, the number of modes is controllable, and the interference components are simple, and it is easy to obtain interference spectra with high contrast and regular shapes, which is conducive to demodulating the spectrum and adjusting the free spectral range of the spectrum; at the same time, because the optical fiber does not contact the capillary, the optical fiber has good vibration performance and the advantage of high sensitivity; by controlling the thickness of the film layer, it is also convenient to adjust the detection frequency range of the sensor.

The invention provides a high-sensitivity measurement method based on a single interferometer and a vernier effect, and belongs to the field of optical signal processing, and the method comprises the steps: determining a central wavelength according to the spectrum of a sensing interferometer; turning over the spectrum of the sensing interferometer along a horizontal axis of the wavelength direction of the spectrum of the sensing interferometer by taking the central wavelength as a center to obtain a spectrum of a reference interferometer; performing signal processing on the sensing interferometer spectrum and the reference interferometer spectrum to obtain an output spectrum; extracting a vernier envelope of the output spectrum, and obtaining a free spectrum range of the vernier envelope according to the vernier envelope; and obtaining a sensitivity amplification factor based on the vernier effect according to the free spectral range enveloped by the vernier and the free spectral range of the sensing interferometer. According to the method disclosed by the invention, high-sensitivity measurement can be completed only by using a single interferometer, two interferometers with similar free spectral ranges do not need to be prepared by an accurate and complex manufacturing technology any more, the cost of the whole detection scheme is saved, and the method has great practicability.

The invention discloses an all-optical tuning controllable optical comb generation method based on a functionalized echo wall mode optical micro-bottle cavity. Comprising a 1550nm narrow linewidth continuous wave laser, a single-mode fiber, an erbium-doped fiber amplifier, a polarization controller, an optical isolator, a functionalized micro-bottle cavity-fiber taper coupling system, an optical attenuator, a spectrum analyzer and a 1550nm power tunable laser. The free spectral range of the microcavity is reduced by utilizing the unique axial characteristic of the echo wall mode microbottle cavity, the axial mode microcavity optical frequency comb with the small free spectral range is generated, the functionalized microbottle cavity is prepared based on an all-optical tuning method, and the generated axial mode microcavity optical frequency comb is tuned through the photo-thermal material titanium dioxide, so that the optical frequency comb with the small free spectral range is obtained. And remarkable spectral range tuning is realized. The limitation that the WGM microcavity optical frequency comb cannot be effectively tuned due to a large free spectral range is solved, and practical application of the microcavity optical frequency comb in the fields of optical communication, optical frequency synthesis and the like is facilitated.

This application relates to thin-film filters for tunable lasers. A thin-film device for a wavelength-tunable semiconductor laser is also provided. The device includes a cavity located between a high-reflectivity surface and an anti-reflectivity surface, the cavity being designed to emit laser light with wavelengths within a tunable range defined by two vernier ring resonators having a joint free spectral range between a first wavelength and a second wavelength. The device also includes a film comprising multiple pairs of first and second layers, the first and second layers being stacked sequentially on the outer side of the high-reflectivity surface. Each layer in each pair has a respective optical thickness of one unit, except for one of the first or second layers in a pair having a larger optical thickness. The film is configured to produce an internal reflectivity of at least greater than 90% of the laser light from the high-reflectivity surface for wavelengths within the tunable range starting from the first wavelength, but for wavelengths within a 25 nm range surrounding the second wavelength, the internal reflectivity of the laser light is at least less than 50%.

Optical transceiver architecture utilizing micro-ring modulators and micro-ring resonators configured to route resonant wavelengths of light injected into each micro-ring resonator's input port and through port to that micro-ring resonator's drop port and add port, respectively. The micro-ring resonators drop two distinct streams of data modulated onto the same optical wavelength, or two wavelengths separated by an integer number of free spectral ranges coupled into the micro-ring resonators in two different directions.