Patent Application
20050276287
The present invention relates generally to the field of laser devices.
Laser light producing devices (hereinafter, simply laser devices) are commonly employed in communication applications. In particular, distributed feedback (DFB) laser devices are commonly employed in wavelength division multiplexing (WDM) systems. Typically, depending on the applications, DFB laser devices of different wavelengths are required. Historically, different parts designed for different wavelengths are manufactured and stocked to meet the different wavelength needs. The approach is inefficient and costly.
More recently, attempts have been made to manufacture tunable DFB laser devices that support multiple wavelengths. Typically, these tuner laser devices include laser stripes configured to generate laser light of different wavelengths. Further, a passive combiner is integrated to combine the outputs of the laser stripes. To generate a laser light of a desired wavelength, appropriate selected one or ones of the laser stripes are electrically activated.
However, passive combiners are known to have an intrinsic minimum loss that increases with the number of laser stripes integrated with the laser device. Thus, it is difficult to implement such a device to support a wide range of wavelengths. Further, the approach increases the real estate requirement of the laser devices, and decreases manufacturing yield (due to the added complexity from integrating the passive elements).
The present invention will be described by way of exemplary embodiments, but not limitations, illustrated in the accompanying drawings in which like references denote similar elements, and in which:
a-3b illustrate the operational principles of the laser device of
a-4b illustrate a top view of the MEMS with a movable lens of
Illustrative embodiments of the present invention include, but are not limited to, a laser device, and system having such a laser device.
Various aspects of the illustrative embodiments will be described using terms commonly employed by those skilled in the art to convey the substance of their work to others skilled in the art. However, it will be apparent to those skilled in the art that the present invention may be practiced with only some of the described aspects. For purposes of explanation, specific numbers, materials, and configurations are set forth in order to provide a thorough understanding of the illustrative embodiments. However, it will be apparent to one skilled in the art that the present invention may be practiced without the specific details. In other instances, well-known features are omitted or simplified in order not to obscure the illustrative embodiments.
The phrase “in one embodiment” is used repeatedly. The phrase generally does not refer to the same embodiment; however, it may. The terms “comprising”, “having” and “including” are synonymous, unless the context dictates otherwise.
Referring now to
Laser stripes 108 include a number of stripes, one or more of which can be selectively activated to facilitate production of laser light for a desired wavelength. Together, they (with the assistance of MEMS 102) enable laser light of a selected one of a wide range of wavelengths to be selectively produced. Resultantly, for a given desired range of selectable wavelength (and other factors, such as volume and overhead cost, being equal), a relatively lower cost tunable laser device may be produced.
In various embodiments, each stripe or group of stripes are further designed such that when they are activated to produce laser light of a desired wavelength, the wavelength of the laser light outputted may be further fine tuned by controlling the thermal condition of the optoelectronic device hosting the activated laser stripe or stripes. In various embodiments, one or more optoelectronic devices may be employed to host laser stripes 108. Selection of the one or more stripes, including controlling of the thermal condition of the optoelectronic device hosting the activated laser stripe or stripes may be effectuated via any one of a number of techniques.
MEMS 102 is designed such that lens 106 may be electromechanically moved at least in either direction along the X-axis (as illustrated by
In various embodiments, to accommodate manufacturing tolerance, MEMS 102 is further designed such that lens 106 may also be electromechanically moved in either direction along the Y-axis to appropriately align lens 106 with the activated laser stripes, to focus the laser light outputted to an output medium. In various embodiments, movement along a selected one of the X and −X directions may also be optionally effectuated, substantially at the same time, when effectuating movement along the Y/−Y direction.
The ability for lens 106 to be moved in 1 or 2 directions may be effectuated by providing a number of movable elements to MEMS 102, attaching these movable elements to lens 106 to move it in the desired X (and/or Y) direction(s).
Referring now also to
References to the edges of MEMS 102 as “top”, “bottom” and “side” are for ease of understanding, and should not be read as limiting to embodiments of the invention. The edges could have been referenced in other manners if MEMS 102 is described from another point of view.
Still referring to
In various embodiments, comb drives 402a, 402b, 402c, and 402d may be selectively activated in combination with variable intensities, that are the same or different from each other, to provide movement in one or two directions. The amount of movement in each of the directions is dependent on the intensity levels of activation, and the relative difference between the selected comb drives being activated in combination.
In alternate embodiments, the present invention may be practiced with other other drive arrangements of the like.
Thus, operationally, to effectuate output of a laser light of a desired wavelength, one or more appropriate ones of the laser stripes 108 are activated to produce light with a wavelength in the neighborhood of the desired wavelength. The operation may also be referred to as coarse selection. Thereafter, the activated laser stripes 108 may be thermally controlled to provide the laser light of the desired wavelength. The operation may also be referred to as fine tuning of the laser light outputting.
Thereafter, before, or substantially concurrent with the above described coarse and fine tuning operations, lens 106 may be moved such that it is positioned properly to optically couple the laser light output onto an output medium, e.g. a fiber.
Accordingly, a more cost effective tunable laser device may be produced.
Still referring to
In various embodiments, the tasks performed by processor 512 may include controlling the earlier described selective activation of laser stripes 108, their fine tuning, and moving of lens 106. In alternate embodiments, the actual controlling may be delegated to one or more other controllers (not shown). That is, processor 512 effectuates the desired controls via these other controllers. Accordingly, for the claims, a processor may be referred to as a controller or vice versa, i.e. the terms are to be considered interchangeable.
Further, in various embodiments, data routing system 502 may also include one or more sensors (516) to collect one or more performance metrics on laser device 100, e.g. the wavelength and the power of outputted laser light, temperatures of one or more locations, and so forth. The sensors may also be coupled to processor 512 (or its agents, the “downstream” controllers, if applicable), to effectuate their controls (periodically or in real time), further in view of the data collected for the performance metrics. In various embodiments, at least some of the sensors are disposed outside network interface module 504.
Except for the incorporation of laser device 100 with network interface module 504, elements 502-504 represent a broad range of these elements known in the art or to be designed
In various embodiments, example system 500 may be a router, a switch, a gateway, a server, and so forth.
Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a wide variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described, without departing from the scope of the present invention. This application is intended to cover any adaptations or variations of the embodiments discussed herein. Therefore, it is manifestly intended that this invention be limited only by the claims and the equivalents thereof.
