Abstract:
A laser comprising a lasing cavity, having a lasing medium and primary optical feedback means in the form of a facet at either end of the cavity is described. The laser includes secondary optical feedback means in the form of one or more effective refractive index perturbations in the lasing cavity with at least one of the facets configured to preferentially reflects a specific wavelength or band of wavelengths. A method of manufacturing such a laser is also described as is a method of suppressing side modes in a lasing device.
Abstract:
Purely gain-coupled diffraction gratings may be realized for use in QCLs and other edge emitting lasers that lack a typical p-n junction. The periodic, typically heavily n-doped regions of doped diffraction gratings are replaced with p-type regions having significantly lower doping.
Abstract:
An optical transmitter comprises an array of modulated sources having different operating wavelengths approximating a standardized wavelength grid and providing signal outputs of different wavelengths. Signal outputs of the modulated sources are optically coupled to inputs of the wavelength selective combiner to produce a combined signal output from the combiner. The wavelength selective combiner has a wavelength grid passband response approximating the wavelength grid of the standardized wavelength grid. A first wavelength tuning element is coupled to each of the modulated sources and a second wavelength tuning element is coupled to the wavelength selective combiner. A wavelength monitoring unit is coupled to receive a sampled portion the combined signal output from the wavelength selective combiner. A wavelength control system is coupled to the first and second wavelength tuning elements and to the wavelength monitoring unit to receive the sampled portion of the combined signal output. The wavelength control system adjusts the respective wavelengths of operation of the modulated sources to approximate the standardized wavelength grid and for adjusting the optical combiner wavelength grid passband response to approximate the standardized wavelength grid.
Abstract:
A method is disclosed for monitoring and controlling the bit error rate (BER) in an optical communication network where an optical receiver in the optical transmission network is a monolithic photonic integrated circuit (RxPIC) chip. The method includes the steps of decombining on-chip a combined channel signal received from the network and then monitoring a real time bit error rate (BER) of a decombined channel signal. The determined BER is then communicated, such as through an optical service channel (OSC) to an optical transmitter source that is the source of origin of the channel signal. Based upon the determined BER, the chirp of a channel signal modulator at the optical transmitter source that generated the monitored channel signal is adjusted by, for example, adjusting its bias. The same channel signal received at the RxPIC chip can be monitored again to determine if an acceptable level for the BER has been achieved by the previous chirp adjustment.
Abstract:
An optical transmitter comprises a monolithic transmitter photonic integrated circuit (TxPIC) chip that includes an array of modulated sources formed on the PIC chip and having different operating wavelengths approximating a standardized wavelength grid and providing signal outputs of different wavelengths. A wavelength selective combiner is formed on the PIC chip having a wavelength grid passband response approximating the wavelength grid of the standardized wavelength grid. The signal outputs of the modulated sources optically coupled to inputs of the wavelength selective combiner to produce a combined signal output from the combiner. A first wavelength tuning element coupled to each of the modulated sources and a second wavelength tuning element coupled to the wavelength selective combiner. A wavelength monitoring unit is coupled to the wavelength selective combiner to sample the combined signal output. A wavelength control system coupled to the first and second wavelength tuning elements and to said wavelength monitoring unit to receive the sampled combined signal output. The wavelength control system adjusts the respective wavelengths of operation of the modulated sources to approximate or to be chirped to the standardized wavelength grid and for adjusting the optical combiner wavelength grid passband response to approximate the standardized wavelength grid.
Abstract:
A method and apparatus operates an array of laser sources as an integrated array on a single substrate or as integrated in an optical transmitter photonic integrated circuit (TxPIC) maintaining the emission wavelengths of such integrated laser sources at their targeted emission wavelengths or at least to more approximate their desired respective emission wavelengths. Wavelength changing elements may accompany the laser sources to bring about the change in their operational or emission wavelength to be corrected to or toward the desired or target emission wavelength. The wavelength changing elements may be comprise of temperature changing elements, current and voltage changing elements or bandgap changing elements. Identification tags in the form of low frequency tones may be applied relative to respective laser source outputs with a different frequency assigned to each laser source so that each laser can be specifically identified in a feedback control for providing correction signals to the wavelength changing elements to correct for the emission wavelength of respective laser sources.
Abstract:
An optical probe and a method for testing an optical chip or device, such as an photonic integrated circuit (PIC), to provide for testing of such devices or circuits while they are still in their in-wafer form and is accomplished by using a an optical probe for interrogation of the circuit where an access is provided in the wafer to one or more of such in-wafer devices or circuits. As one example, the interrogation may be an interrogation beam provided at the access input to the in-wafer device or circuit. As another example, the interrogation may be an optical pickup from the access input to the in-wafer device or circuit.
Abstract:
A semiconductor laser with a semiconductor substrate, a laser layer arranged on the semiconductor substrate, a waveguide arranged parallel to the laser layer and a strip shaped grating structure is disclosed. The laser layer, the waveguide and the grating are arranged a configuration which results in weak coupling between the laser light and the grating structure, so that the laser light interacts with an increased number of grating elements. A process for the production of such a semiconductor laser is also disclosed.
Abstract:
An optical transport network comprises a monolithic transmitter photonic integrated circuit (TxPIC) InP-based chip and a monolithic receiver photonic integrated circuit (RxPIC) InP-based chip.
Abstract:
An optical transport network comprises a monolithic transmitter photonic integrated circuit (TxPIC) InP-based chip and a monolithic receiver photonic integrated circuit (RxPIC) InP-based chip.