A transmitter and a receiver for an optical telecommunication system of the WDM type are disclosed. In one aspect, the transmitter uses a chromato-temporal encoder which, with each block of symbols to be transmitted, associates a code matrix, where each element of the matrix corresponds to a wavelength and a use of the channel. The transmitter includes multiple modulators, where each modulator modulates a laser beam at a wavelength during a use of the channel by an element corresponding to the code matrix. The beams modulated in this manner are multiplexed in an optical fiber. Another embodiment using both a wavelength and a polarization encoding is also proposed.

An undersea long-haul transmission system includes an optical fiber transmission span and a coherent detection and digital signal processing module for providing dispersion compensation. The transmission span includes at least one fiber pair comprising substantially equal lengths of a positive-dispersion first fiber and a negative-dispersion second fiber that are configured to provide a signal output at transmission distances greater than 10,000 km, in which the combined accumulated dispersion across the operating bandwidth does not exceed the dispersion-compensating capacity of the coherent detection and digital signal processing module. Further described is a fiber for use in an undersea long-haul transmission span. At a transmission wavelength of 1550 nm, the fiber has a dispersion coefficient in the range of −16 to −25 ps/nm·km, and a dispersion slope in the range of 0.04 to 0.02 ps/nm2·km.

One aspect provides an optical communication system. The system includes an optical-to-digital converter, a frequency estimator and a symbol synchronizer. The optical-to-digital converter is configured to receive an optical OFDM bit stream including an OFDM symbol bearing payload data and a symbol header preceding the OFDM payload data. The frequency estimator is configured to determine a carrier frequency offset of the payload data from the symbol header. The symbol synchronizer is configured to determine a starting location of the payload data within the bit stream by cross-correlating a synchronization pattern within the symbol header with a model synchronization pattern stored by the symbol synchronizer.

A fiber optic data transmission system includes an optical fiber and a data transmitter having a first laser having a first wavelength, a first phase modulator for phase modulating light from the first laser as a function of a first data input stream so as to create a first phase-modulated output data stream, a second laser having a second wavelength different from the first wavelength, and a second phase modulator for phase modulating light from the second laser as a function of a second data input stream so as to create a second phase-modulated output data stream. The transmitter also includes a combiner combining the first and second output data streams into a phase-modulated optical signal for transmission over the optical fiber.

Methods and apparatus related to the detection of low-rate visible light communication (VLC) signals and the recovery of information communicated by the VLC signals are described. Various methods and apparatus are well suited for embodiments in which a device, e.g., a smartphone, including a camera which uses a rolling shutter. The rolling shutter facilitates the collection of different time snapshots of a received low rate time varying VLC signal with different pixel rows in the image sensor of a frame corresponding to different time snapshots. In some embodiments, demodulation is used to recover and identify a single tone being communicated in a frame from among a plurality of possible alternative tones that may be communicated, each different tone corresponding to a different set of information bits.

A pre-emphasis control method includes calculating an average value of transmission characteristics based on transmission characteristics of a plurality of light beams received by a receiver, and determining that, among signals of the plurality of light beams, a wavelength with a deviation from the average value is a wavelength at which control is to be performed, determining that the wavelength at which control is to be performed and a wavelength adjacent thereto are a group of wavelengths at which control is to be performed, obtaining an average of transmission characteristics of the group of wavelengths at which control is to be performed, and based on a difference between averaged transmission characteristics and respective transmission characteristics of the group of wavelengths at which control is to be performed, changing a light intensity output from each transmitter that transmits a group of wavelengths at which control is to be performed.

A signal transmission device drives a light-emitting element and outputs an optical signal depending on a data signal from an electronic device. The device includes an element driving portion which supplies a driving current to the light-emitting element, wherein the driving current is obtained by superimposing a modulation current on a bias current, the modulation current being dependent on the data signal indicating emitting information of the light-emitting element. A temperature compensation portion of the device controls the bias current and the modulation current depending on the temperature so that a temperature-current characteristic of the light-emitting element is reproduced based on the voltage which is dependent on the temperature and the voltage which is independent from the temperature, thereby performing current control depending on the temperature.

Provided is a polarization separation device which converges filter coefficients used in polarization separating process more quickly. The polarization separation device according to the present invention comprises: a first filter means 11 which applies filtering process on each of first and second input signals, which are detected from an received optical signal, with elements of a characteristic matrix representing the inverse characteristics of an optical transmission path as filter coefficients, and uses each of the filtered signals to output a first output signal; a second filter means 12 which applies filtering process on each of the first and second input signals with the other elements of the characteristic matrix as filter coefficients, and uses each of the filtered signals to output a second output signal; a filter coefficient update means 13 which updates the first filter coefficients using a relation between the elements of the characteristic matrix so as to further reduce both error signals of the first and second output signals; and a filter coefficient update means 14 which updates the second filter coefficients using the relation between the elements of the characteristic matrix so as to further reduce both error signals to the first and second output signals.

Techniques are provided describing a first connector unit that receives first data from a first transceiver and a second connector unit that receives second data from a second transceiver. A switch unit is configured to receive first switch data from the first connector unit at a first data rate and second switch data from the second connector unit at the first data rate. A third connector unit receives the first switch or the second switch data from the switch unit and a second portion of the second data from the second connector unit. The third connector unit also sends the first switch data to a host port when the first connector unit receives the first data and to send the second switch data and the second portion of the second data to the host port when the second connector unit receives the second data.

An optical transceiver that attenuates the EMI radiation leaked therefrom is disclosed. The optical transceiver includes a top cover and the bottom base to form a cavity into which a TOSA, a ROSA, and a circuit are set. At least one of the top cover and the bottom base provides a combed structure in a rear portion of the optical transceiver, where the combed structure has a plurality of T-shaped fins to attenuate the EMI radiation.

An optical transceiver that reduces the EMI radiation leaked therefrom is disclosed. The optical transceiver includes a top cover and the bottom base to form a cavity into which a TOSA, a ROSA, and a circuit are set. The top cover provides a combed structure in a rear portion thereof, where the combed structure has a plurality of fins with a distance preferably less that quarter wavelength λ/4 of the noise wavelength to be reduced. The combed structure operates as a short stub for the electromagnetic wave traveling longitudinally in the cavity.

An apparatus and method for fault indication and localization in a Passive Optical Network (PON) comprising a multistage power splitter (100, 200, 300) with at least one 1:N splitter (120, 221, 222, 321, 322) followed by N items of 2:M splitters (131, 132, 231-233, 331-336), wherein N and M are integers greater than 1. The apparatus also comprises an Optical Time Domain Reflectometry (OTDR) device (110, 210, 310) capable of inserting an OTDR signal into the power splitter (100, 200, 300), and adapted to insert the OTDR signal between the first stage of the at least one 1:N splitter (120, 221, 222, 321, 322) and the second N items of 2:M splitters (131, 132, 231-233, 331-336).

A WDM optical signal is transmitted through a tunable optical filter and is polarization-nulled to find optical signal to noise ratio of individual WDM channels. The polarization nulling can be performed using a heuristic multipoint extrema search method, such as Nelder-Mead method. A plurality of checkpoints can be included in the search to verify the progress and to improve the overall robustness of a real-time polarization nulling.

The present invention refers to a method for adjusting power levels of channels (15) in an optical link (7) of an optical network comprising at least one optical amplifier (9) wherein the power distribution among the channels (15) of the optical link (7) is achieved in function of: target power levels based on the features of corresponding connections and of link physical features,total available power in said at least one amplifier (9),features of control means allowing the power distribution, and wherein for a channel corresponding to a connection having a higher vulnerability characterizing parameter, the tolerated difference between an actual channel power level and the target power level is lower than for a channel corresponding to a connection having a lower vulnerability characterizing parameter.

An optical transport network system includes a plurality of NEs, each transmitting wavelength-multiplexed optical signals. Each NE includes a routing information DB that is used to store reachable area information, which contains identifiers of other NEs in a range within which the optical signals can be transmitted from the own NE without using an REG. A FROM NE includes a path candidate searching unit that searches for a plurality of path candidates for transmitting optical signals from the FROM NE to a TO NE. The TO NE includes a path selecting unit that selects a path for transmitting optical signals from among a plurality of path candidates. The path selecting unit obtains the number of times for which the REG is used for each of the plurality of path candidates; and, based on each number of times that is obtained, selects a path for transmitting the optical signals.

Additional bandwidth is provisioned to layer 2/3 networks by initially provisioning optical wavelength channels to meet incremental needs for additional capacity. When bandwidth requirements grow large enough, a wavelength-sized channel is provisioned to meet the bandwidth needs, and the previously provisioned optical wavelength channels are freed up to be reused for additional growth. The optical wavelength channels may be channelized VLANs mapped to resizable optical channel data units such as ODUflex units.

An optical line termination node has a first connection arrangement for connecting a working fiber, a second connection arrangement for connecting a protection fiber, a transceiver arrangement having first primary link and a first secondary link, and protection switching means configured for being switched either in a working operating state or in a protection operating state.

This invention relates to provisioning wavelength-selective switches and reconfigurable optical add-drop multiplexers to minimize the bandwidth narrowing effect from the optical filters. Novel architectures and methods are disclosed that can significantly reduce bandwidth-narrowing on channels in a reconfigurable WDM network where a large number of optical filter elements are cascaded. Instead of blocking unused channels as in the prior art, unused channels are selectively provisioned depending on the state of their adjacent channels. Unused adjacent channels of an active channel are provisioned to follow the same path as the active channels. As each channels is deployed, the channel frequency is selected so as to minimize bandwidth narrowing.

A method for adjusting an optical signal includes determining a polarization dependent loss (PDL) value associated with the optical signal, determining an angle between the optical signal and one or more axes of PDL, determining an amount of nonlinear phase noise due to PDL and nonlinear effects upon the optical signal based upon the PDL value and the angle, determining a phase rotation based upon the amount of nonlinear phase noise, and applying the phase rotation to the optical signal.

An optical module that outputs a wavelength multiplexed optical signal is disclosed. The optical module provides at least first to third optical source, a wavelength multiplexer, a polarization rotator, and a polarization multiplexer. The optical sources each outputting first to third optical signals with a wavelength different from others. The wavelength multiplexer multiplexes the first optical signal with the third optical signal. The polarization rotator rotates the polarization vector of one of the multiplexed first and third optical signals and the second signal by substantially 90°. The polarization multiplexer multiplexes the polarization rotated optical signal with the second optical signal.

Optical fiber-based distributed communications systems that provide and support both RF communication services and digital data services are disclosed herein. The RF communication services and digital data services can be distributed over optical fiber to client devices, such as remote antenna units for example. In certain embodiments, digital data services can be distributed over optical fiber separate from optical fiber distributing RF communication services. In other embodiments, digital data services can be distributed over common optical fiber with RF communication services. For example, digital data services can be distributed over common optical fiber with RF communication services at different wavelengths through wavelength-division multiplexing (WDM) and/or at different frequencies through frequency-division multiplexing (FDM). Power distributed in the optical fiber-based distributed communications system to provide power to remote antenna units can also be accessed to provide power to digital data service components.

The device identification apparatus includes: a remote controller signal detecting section for detecting an optical signal from a remote controller; a receiving section for receiving the optical signal from the remote controller; a signal decryption section for decrypting the optical signal received by the receiving section; and a transmitting section for transmitting a device identification signal when the optical signal is a device selecting signal, and configured such that operations of the receiving section, the signal decryption section, and the transmitting section are started in response to a detecting signal of the remote controller signal detecting section, thereby realizing a device identification apparatus in which power consumption during standby is minimized.

An optical transceiver of one embodiment includes a transmitter optical subassembly to transmit an optical signal, a receiver optical subassembly to receive an optical signal, a mother board, a daughter board, and a housing. The mother board mounts electronic circuits that electrically communicate with the optical transmitter optical subassembly and the receiver optical subassembly. The daughter board mounts other electronic circuits that electrically communicate with the optical transmitter optical subassembly and the receiver optical subassembly. The daughter board has an extra area mounting a portion of the other electronic circuits. The housing defines a space for installing the optical transmitter optical subassembly, the receiver optical subassembly, the mother board, and the daughter board. The extra area is disposed outside the space.

Intrapersonal communication systems and methods that provide an optical digital signal link between two or more local devices are disclosed. In some embodiments, the system includes a first signal converter disposed at a first end of the optical digital signal link and configured to convert between electrical digital signals from a first local device and optical digital signals from the optical digital signal link. The system can include an optical connector having a non-contact portion configured to couple optical digital signals between the first signal converter and the optical digital signal link across a gap. The system can include a second signal converter disposed at a second end of the optical digital signal link and configured to convert between electrical digital signals from the second local device and optical digital signals from the optical digital signal link.

In the present invention, wasted power consumption caused when a clock and data recovery unit in an optical network unit in a PON system is activated from a power-saving state is reduced and rapid, secure communication is performed. A clock and data recovery unit includes a phase-locked loop that can be set to normal mode or power-saving mode and that includes a voltage-controlled oscillator and recovers a clock signal and a data signal from input signals. The clock and data recovery unit includes a reference clock multiplier circuit that multiplies a reference clock signal and outputs the multiplied reference clock signal; and a frequency training loop that includes the same voltage-controlled oscillator and performs synchronous oscillation training by the voltage-controlled oscillator using the reference clock multiplier circuit before the phase-locked loop transitions from power-saving mode to normal mode.

The invention relates to embedding data symbols of a data signal into a luminance output of an illumination device. The device includes a controller configured for receiving a first base pattern and a second base pattern within a frame period, and generating a shifted second pattern by phase shifting the second base pattern within the frame period with respect to the first base pattern in response to the data signal such that the data symbols are embedded in the luminance output of the device. The device also includes a first light source configured to generate a first luminance output in response to the first base pattern and a second light source configured to generate a second luminance output in response to the shifted second pattern. The first and second luminance outputs have different output spectra and the luminance output of the illumination device comprises both the first and second luminance outputs. With this approach, the short-time average light output of the illumination device remains constant, decreasing the visible flicker and allowing the use of lower switching frequencies relative to the prior art approaches.

A repeater includes a reception part configured to receive an optical signal transmitted by wavelength division multiplexing from a preceding repeater in a path from a source to a destination; a determination part configured to determine the channel allocation of the signal received by the reception part by determining a bit rate and a modulation technique with respect to each of channels in the received signal; and a detection part configured to detect a prohibited channel not to be included in the optical signal to be transmitted from the repeater, based on the channel allocation and a predetermined criterion.

Disclosed is a transmitter optical module which includes a first package generating an optical signal; a second package bonded with the first package by using chip-to-chip bonding, having a silicon optical circuit platform structure, and amplifying the optical signal; and an optical waveguide forming a transmission path of the optical signal from the first package to the second package.

A cutting insert (130) is formed to be rotationally symmetric with respect to an axis line (C3) of a height direction and to be planarly symmetric with respect to a virtual plane of the insert (VS1), an axis line (C2) of a traverse direction is gradually inclined toward the front of a rotational direction around which a workpiece (W) rotates moving toward a first traverse direction (C2A), an axis line (C1) of a longitudinal direction extends toward a lower surface side of an insert body (131) so as to approach a virtual plane of the tool moving toward a first longitudinal direction (C1A), and one corner portion (143C) in the other cutting edge (132B) is disposed further toward a first traverse direction (C2A) than one corner portion (143A) in one cutting edge (132A).

A toolholder assembly includes a toolholder body having a coolant passage and a cutting insert seated within a recess of the body. The cutting insert includes an insert orifice extending between a top face and a bottom face that aligns with the coolant passage. A lock pin includes a lock pin orifice that aligns with and is in fluid communication with the coolant passage of the body. The lock pin orifice has an outlet port to allow the fluid to flow through the lock pin orifice and exit through the outlet port. A lock pin ring includes a coolant port in fluid communication with the outlet port of the lock pin to effectively discharge cooling fluid in the direction of a cutting area of the cutting insert.

Milling cutter and method of operating same, and other machine tools, and an adjustment mechanism therefor. A cutting insert is adjusted by moving a resilient web with an adjusting screw.

A cutting insert of the present invention includes an upper surface; a lower surface; a side surface; a cutting edge which is located along an intersection of the upper surface and the side surface, and comprises a major cutting edge, a flat cutting edge, and a minor cutting edge located between the major cutting edge and the flat cutting edge; and a land part located along the cutting edge on the upper surface. The land part includes a minor cutting edge land portion located correspondingly to the minor cutting edge. The minor cutting edge land portion is inclined downward toward a central part of the upper surface. The present invention also provides a cutting tool including the cutting insert, and a method of manufacturing a machined product by using the cutting tool.

A tool for both severing the end of a pipe and beveling the cut end includes a spiral cutting mill having an elongate end received in the bore of a frustoconical shell cutter. The shell cutter is locked for rotation with the cutting mill such that a single tool has two cutting surfaces, one for severing a length of pipe and one for beveling the outer edge thereof.

It is an object of the present invention to provide a sintered cBN compact having excellent wear resistance and fracture resistance even in machining centrifugally cast iron having a property of being difficult to machine, and to provide a sintered cBN compact tool. A sintered cBN compact of the present invention contains 20% by volume or more and 65% by volume or less of cBN and, as a binder, 34% by volume or more and less than 80% by volume of Al2O3, at least one selected from the group consisting of nitrides, carbides, carbonitrides, borides, and boronitrides of Zr and solid solutions thereof (hereinafter, referred to as “X”), and ZrO2, the total amount of X and ZrO2 being 1.0% by volume or more and 6.0% by volume or less, the volume ratio of ZrO2 to Al2O3, ZrO2/Al2O3, being 0.010 or more and less than 0.100, in which the ratio Itetragonal ZrO2(101)/IαAl2O3(110) is 0.1 or more and 3 or less, where Itetragonal ZrO2(101) is the intensity of the (101) plane of tetragonal ZrO2 and IαAl2O3(110) is the intensity of the (110) plane of αAl2O3 among X-ray diffraction peaks of the sintered cBN compact.

A cutting insert has at least first and second side surfaces, with a chip-control arrangement. The chip-control arrangement includes at least one projection disposed at an intersection of a corner of the cutting insert. When the chip-control arrangement includes two projections they can be disposed symmetrically on both sides of the intersection. Each of the at least one projections is elongated and extends longitudinally along an associated side surface.

A cutting insert is capable of boring or drilling without the formation of a prepared hole in a workpiece. A cutting edge includes a cutting edge portion extending from the outer peripheral side to the tool center axis side of a cutting tool body when the cutting insert is attached to a mounting seat, reaching a first plane including the tool center axis, and traversing from one side to the other side of a second plane which is perpendicular to the first plane and which includes the tool center axis.

A cutter insert assembly for a drill bit for boring into the earth, comprising a super-hard structure clampable to a support body by means of a clamp mechanism; the clamp mechanism comprising opposed or opposable compression members connected or connectable by a tension member capable of sustaining a clamping force between the compression members when the cutter insert assembly is in a clamped condition, in which condition the compression members exert opposing compressive forces on the super-hard structure and the support body, operable to clamp the super-hard structure to the support body, and in which condition the cutter insert assembly is self-supporting and capable of being mounted onto a drill bit body.

A cutting tool includes a polygonal cutter body and an end cutting insert for chipforming machining mounted in a serrated seat disposed at an axial end of the cutter body. A bottom surface of the insert has a plurality of parallel serrations meshing with corresponding serrations of the seat. The serrations extend transversely relative to the longitudinal axis for resisting axially rearward cutting forces applied to the insert. The seat is formed directly by the cutter body, or by a shim disposed beneath the insert. The shim is provided with a downward lip to transfer axial forces to the cutter body. The insert can be square or triangular, wherein the serrations are in the form of a plurality of sets of parallel serrations disposed adjacent respective cutting edges.

Cartridge for supporting at least one cutting insert and for being received on a tool body is disclosed. At least a first portion of the cartridge may be stationary mounted and the cartridge includes at least one pocket for receiving a cutting element. A coarse and a fine adjustment means are provided by means of which at least a second portion of the cartridge including the pocket may be moved with respect to the tool body and wherein the coarse and the fine adjustment means are merely provided at the cartridge.

Electrode milling cutter for machining spot welding electrodes, said electrode milling cutter having one or more milling edges, wherein at least one of the milling edges is interrupted by one or more cut-outs at one or more points. The invention also relates to a milling device and to an apparatus for subsequently machining spot welding electrodes.

A cutting insert includes an upper surface; a lower surface; a side surface which is connected to each of the upper surface and the lower surface and includes a first side surface, a second side surface and a third side surface being adjacent to each other in order; an upper cutting edge including an upper major cutting edge located at an intersection of the upper surface and the first side surface, and an upper flat cutting edge located closer to the upper major cutting edge in an intersection of the upper surface and the second side surface; and a lower cutting edge including a lower major cutting edge located at an intersection of the lower surface and the third side surface, and a lower flat cutting edge located closer to the lower major cutting edge in an intersection of the lower surface and the second side surface. The second side surface comprises an upper flank surface connected to the upper flat cutting edge, and a lower flank surface connected to the lower flat cutting edge. As going from the upper surface to the lower surface, the upper flank surface is closer to a central axis extending between the upper surface and the lower surface and the lower flank surface is separated from the central axis in a side sectional view. A cutting tool including the cutting insert, and a method of manufacturing a machined product by using the cutting tool are also provided.

In a cutting tool for chip removing machining a holder for a cutter has a body received therein and movable with surfaces to bear against the cutter for defining the position of the cutter in the direction of an intended axis of rotation of the holder as well as a screw which may be screwed in a threaded bore in the holder. Spring members are arranged to act between the holder and the body for biasing the body against said screw portions.

A cutting insert having excellent chip discharge performance is provided. The cutting insert (1) according to an embodiment of the present invention includes an upper surface (2), a lower surface (3), a side surface (4) connected to the upper surface (2) and the lower surface (3), and a cutting edge (5) which is located at an intersection of the upper surface (2) and the side surface (4), and includes a major cutting edge (51) and a flat cutting edge (52). The major cutting edge (51) includes a major cutting section (512) which has a concave shape and is inclined downward as a straight line connecting both ends thereof is away from the flat cutting edge (52) in a side view. A cutting tool (11) according to an embodiment of the present invention includes the cutting insert (1) and a holder (10) configured to attach the cutting insert (1) thereto.

An upper surface of a cutting insert includes a first rake face and a second seating surface. A lower surface of the cutting insert includes a second rake face and a first seating surface. The cutting edge includes a first cutting edge portion formed at a crossing edge line portion between the first rake face and a flank face and a second cutting edge portion formed at a crossing edge line portion between the second rake face and the flank face. The first cutting edge portion and the crossing edge line portion between the first seating surface and the flank face are positioned opposite each other. The second cutting edge portion and the crossing edge line portion between the second seating surface and the flank face are positioned opposite each other.

A cutting insert according to an embodiment of the present invention includes an upper surface; a lower surface; a side surface located between the upper surface and the lower surface; at least one concave part extending in a thickness direction in the side surface, and having one end thereof located at the upper surface; and a cutting edge which is located at an intersection region of the upper surface and the side surface, and is divided into a plurality of divided cutting edges with the at least one concave part interposed therebetween. The upper surface includes a first raised part located inwardly of the at least one concave part, and a plurality of second raised parts respectively located inwardly of the plurality of divided cutting edges. The plurality of the second raised parts are located inward compared to one end of the first raised part close to the cutting edge in a top view. A cutting tool including the cutting insert, and a method of manufacturing a machined product using the cutting tool are also provided.

A cutting insert according to an embodiment of the invention includes: an upper surface; a lower surface; a side surface which is connected to each of the upper surface and the lower surface, and includes a first side surface and a second side surface adjacent to each other; and a cutting edge including a major cutting edge located at an intersection of the upper surface and the first side surface, and a minor cutting edge located at an intersection of the upper surface and the second side surface. The upper surface includes a rake surface which is located along the major cutting edge, and is inclined downward as the upper surface separates from the major cutting edge. The second side surface includes a second upper constraining surface and a second lower constraining surface in order as the second side surface goes from the upper surface to the lower surface. The second upper constraining surface is inclined inward at an inclination angle α1 with reference to a central axis extending between the upper surface and the lower surface. The second lower constraining surface is continuous with the second upper constraining surface, and is inclined outward at an inclination angle α2 with reference to the central axis. A cutting tool with the cutting inserts, and a method of manufacturing a machined product by using the cutting tool are also provided.

A double-sided cutting insert may generally comprise a top surface, a bottom surface, at least one side surface interconnecting the top surface and the bottom surface and forming at least one cutting edge, a through hole extending between the top surface and bottom surface, wherein each of the top surface and bottom surface comprise at least one anti-rotation element. The cutting insert may comprise a single anti-rotation element on the top surface and a single anti-rotation element on the bottom surface. The anti-rotation element may be proximate to the through hole. A cutting tool using the cutting inserts, as well as methods of making and using the same are also described.

A cutting insert is provided with a plurality of cutting portions formed at the intersection portion of each end surface and a peripheral surface. Each cutting portion includes first and second cutting edges. First corners and second corners which differ in their internal angles are alternately formed in each end surface. An internal angle of the first corner is smaller than an internal angle of the second corner. Each first cutting edge has a portion extending to approach the median plane as a distance from a corresponding first corner increases. A first side surface portion extending on the peripheral surface from each first cutting edge forms an insert internal obtuse angle, and a second side surface portion extending on the peripheral surface from each second cutting edge forms an insert internal acute angle.

Provided is a surface-coated cemented carbide insert obtained by containing at least WC powder and Co powder as raw materials, including a WC-based cemented carbide obtained by forming and sintering mixed raw materials containing at least any of (a) Zr compound powder, Nb compound powder, and Ta compound powder, (b) complex compound powder of Nb and Ta, and Zr compound powder, (c) complex compound powder of Nb, Ta, and Zr, (d) complex compound powder of Nb, Zr, and Ta compound powder, and (e) complex compound powder of Ta and Zr, and Nb compound powder, as essential powder components, as a substrate, and forming a hard coating layer on the substrate by vapor deposition, in which a Co enrichment surface region is formed in a substrate surface, Co content in the Co enrichment surface region satisfies to be between 1.30 and 2.10 (mass ratio) of Co content in cemented carbide.

A roughing end mill comprises an end mill body and plural inserts which are placed on an outer circumference of the end mill body with a predetermined distance apart from each other in the axial direction of the end mill body, wherein the plural inserts form plural insert rows which are provided in a circumferential direction of the end mill body, where the inserts are offset in the axial direction from each other between the different insert rows which are adjacent in the circumferential direction. The inserts have waveform cutting edges which face towards an outer circumferential side of the end mill body. One insert of one insert row and an insert of another insert row are positioned such that the waveform cutting edges of each of these inserts make up a waveform cutting edge row whose phase is continuous on a rotation trajectory around the axis.